Why? Even in a completely tolerant world, homosexuality is going to lead to at least modestly inferior life outcomes (smaller dating pool, harder to enjoy the rewards of parenthood, etc). If a person is by nature going to suffer those hardships, certainly we shouldn't add to it with bigotry and probably we should try to help them in at least some ways, but why is it *good*?
There are people who believe that it is *good* that some people are congenitally deaf. And, as we've seen here a couple of times, people who think that it is *good* that some people suffer various mental illnesses. Do you share that view, in the name of tolerance or diversity or whatever?
A young, unmarried mother might have different genes to pass to the child. The more experience a child has at running the family, when the parents are younger and less experienced with more energy to try to be good parents.
"You may be able to think of others besides these."
Maybe older siblings compete with younger siblings in various ways, and, *being older*, naturally win. e.g. maybe older siblings are much more successful at bullying younger siblings than vice-versa.
But they don't always win. They're better at structured reward activities but more maladjusted to social situations seeped in ambiguity - essentially, dealing with peers of various proclivities vs manipulating/pleasung their parents
That doesn't square well with the "path finder" theory. Older siblings have to fight all the fights with the parents, whereas the younger siblings generally profit from the results without having to put in as much of a fight on their own.
I was specifically critical of the "bossing the parents around" statement. Due to the "path finder" aspect of the oldest sibling, I'd argue that younger siblings get to boss around the parents much more often than older siblings.
I agree with your idea though that having to assert yourself on those arguments might provide good practice for later life.
I could have been more clear in my first post though.
Seems like it. Anecdotally (I don't even remember if I participated in the survey) this lines up perfectly with how I would describe myself and my sibling.
This jives with my experience as the youngest sib from 3 boys. Although as a counter, my current age is 29, older sibs are 34 and 35 and I'm the only ACX reader of them :-S
For sure! Having watched a 3 and a 5 year old interact for 3 years, it seems like being a younger sibling means spending a LOT more time being bossed around by someone 2 years older than you. Like, multiple hours per day minimum 😬
Oddly, with my kids it is the opposite. The oldest girl got pushed around by the middle girl, now the youngest pushes around the middle. They are all girls so there isn't boy levels of pushing around, but generally when there is "not playing nicely" behavior it is the younger pulling dominance.
Are children with experience being a bully, or experience effortlessly prevailing in competitions, more likely to go into a STEM career? That would be counterintuitive.
One (trollish) explanation: people who read ACX are Weird. Most people are bullied/pressured out of being Weird by peers or older siblings, with siblings having a stronger influence. Most 1st borns are Normal, and quash ~all incipient Weirdness in younger siblings. But even if the 1st born is Weird, there's still pressure from peers for the younger siblings to be Normal.
Funny, I was just making the argument to someone else that as an only child, I was basically a firstborn whose weirdness could rage unchecked indefinitely.
I'd guess it's more about younger siblings being more influenced by their older sibling than by their parents. which would probably lead to some advantages and some disadvantages.
Oh, interesting. My own default assumption is actually the opposite of Scott’s (1): being older doesn’t matter for the time during which you have your parents’ undivided attention, but rather for the time afterwards when you have significantly *less* attention because your parents are dealing with a newborn, leading you to develop independence and self-direction much younger.
It would be really interesting to look at families where the oldest child had a significant condition or disability that required lots of parental time and attention, to see what effect that had on the younger sibling(s).
Social first-borns are a third parent to their younger siblings. First-borns are replaced as the cutest thing in the household. This is the effect; not more parental attention. They become parent-like and get attention for being helpful instead of cute.
Yes, one of the flaws in the notion of "shared environment effects small -> parenting doesn't matter" is that parents just straight up teach their children differently, not just differentiate in quantity of attention.
Yes, exactly. This is what I wrote above. The older child becomes the leader, hence looks out on the horizon. The younger follows and competes with the older, whilst the older is following the parents.
Yes, exactly. I see I am at least the third to suggest this effect; I should have read further down so as not to duplicate. Insightful folks, ACX readers :-)
As as oldest child, my experience was something like I didn’t fully register the “child” category before my sister was born. When she came along it became clear that we were not 3 equals (my illusion before). It was not a demotion into less attention so much as it was a demotion into a different category of being. They had allowed me to believe I was one of them; when the sibling came along that was suddenly obviously not true. Never to return again, except in echoes if the sibling were sleeping over at a friend’s, out of the house.
Also if Harris’ “nurture assumption” book is correct and peers play a larger role in development than parents do, the older sibling would be an in-home influential peer for the younger in a way that wouldn’t be reciprocal (usually) unless the younger sibling were dramatically more competent in some way.
I think I intervened between my sister and my parents, in terms of trying to interpret their behavior for her. I was never intentionally the “boss” figure partly because one parent worked almost all the time (dad) and so the center of gravity of the household was not usually present, so not easily challenged.
I’ve definitely known people who had to babysit/quasi-raise their younger siblings and that was not my situation.
This is the opposite of my experience. My closest sibling is six years younger than me, and yet I distinctly recall, even prior to their birth, that I didn't at all think of my parents as equals, or even the same as me. I remember being astonished when I learned that they were once children.
We are assuming the parents are the bosses but I often see the first child being the boss of the parents. Then it's easy to be the boss of any younger children.
I'm understanding that birth order effects are strong for a few years, before dropping off around seven years. Some effects seem stronger after a few years, rather than the minimum difference.
Even with that, a full year of difference (pretty much the minimum biologically), can be pretty dramatic. The difference between two and one is huge, and that's when a lot of these effects are being built into the siblings. Sure, by the time we're talking 19 and 20, that's a tiny difference, but by then the relationships are pretty solidly complete.
This was my first thought, and it makes sense why the effect would get stronger as children get closer in age. We have almost irish twins and for better or worse, have always leaned on the oldest one to help with the younger one (and then the younger two), possibly in age inappropriate ways. Had there been a bigger age gap, we wouldn't have needed to rely on the older as much.
And I think this goes against his natural proclivities. He's very much innately not a "first born" child, or at least his first born traits developed much later, compared to our friends first children, which implies to me it's learned behavior.
The middle I think was innately a first born (basically driven and didn't care what other people thought) and he has been molded into a more typical middle child, turning into a pleaser, which I feel is probably not ideal, but it is what it is at this point.
I think this blog's viewership is mostly 30-somethings? regardless of which age bucket it is, any given adult age bracket should be evenly older or younger siblings, I believe
I remember that Scott said on average, older siblings were only 1 year older than younger siblings (out of the entire pool, obviously, not within the same household) so that is probably not the explanation.
I had this thought too, back when we were looking at the first round of results. I think the fact that the effect is stronger for siblings closer in age, and weaker for siblings farther apart in age, contradicts this hypothesis. If it were just that older people had done more stuff and therefore had had more time to stumble across interesting blogs, then we would expect the effect to get stronger the larger the age gap grows. (Though age might explain the Nobel laureates or whatever.)
If you are sampling individuals, rather than families, why should first siblings be older on average?
Like, if this blog attracts readers between the ages of (simplified example) 20 and 40, then there will be some 20-year-old first-borns whose younger siblings are too young to be eligible, and also some 40-year-old second-borns whose older siblings are too old to be eligible, and presumably these cancel out?
Well, it also wasn't arbitrary in the sense that keeping the family's assets intact rather than dividing them is important, and in the sense that having a very clear line of succession minimises infighting, and ultimogeniture would be too likely to put a baby on the throne.
But I see your point that maybe first-borns are meaningfully distinct in other relevant ways too
This is why I want to ask if the thing SSC is selecting for isn’t conscientiousness first and foremost, with programming being full of conscientious people precisely because there really are right and wrong answers
When I think of a field that demands concientious people, I think Civil Engineering, not programming. When you can compile and test your program in seconds it removes much of the need to get it right the first time.
> When you can compile and test your program in seconds it removes much of the need to get it right the first time.
Most programmers can't do that. You can test a few things, but when you're working with dozens of other developpers on a platform that has thousands of users, either you're concientious, or you're going to increase the support workload a lot.
You can't build your software and run tests whenever you want? I mean, sure, you're not doing integration tests all the time. But most 'careless' errors are caught in syntax and unit tests anyhow.
My experience is largely in small team application development, so I can't speak to life in Big Tech. But it seems to me that most software is obviously more tolerant of carelessness than, say, bridge design. You can catch your errors far more cheaply.
It seems like you're assuming careless development but conscientious testing, and then labeling it as un-conscientious overall. It strikes me as the opposite, a conscientious person can still rely on tests to catch their mistakes as part of their process.
Writing good unit tests sounds conscientious to me, and writing code with syntax (or other basic) errors (that you know you will catch with the tests) isn't necessarily a lack of conscientiousness. (edited for typo)
I can build the software and run the unit tests, but the integration tests are ran every day, and need a few dozens of VM. Syntax errors and unit tests don't catch the big issues, which are logic issues when many services are interacting.
> But it seems to me that most software is obviously more tolerant of carelessness than, say, bridge design. You can catch your errors far more cheaply.
It's not like software is built as tolerant as bridges, since its more tolerant. Business won't let you spend as much time on "safety" as if you were a civil engineering firm, because that would be time mostly wasted. Also, there's a great series comparing regular and software engineering from the pespective of people that have done both, concluding that our work are more similar than different https://www.hillelwayne.com/post/are-we-really-engineers/.
I see that sentiment that "we aren't civil engineers" all the time, and I don't understand it. Especially since most of the time it comes from people with absolutely no experience in civil engineering. Software is not a bridge. But the same techniques can be applied. It's all engineering in the end.
I'd say less that catching programming errors is cheaper, and more that FAILURE to catch them is cheaper. A software bug that makes it all the way into production tends to cause less harm than a design flaw in a bridge or an elevator. Especially if the software in question is, say, a video game.
If you had to produce complex software with literally zero bugs, I expect that would be _ruinously_ expensive.
We don't hold software to anything like the same standard as bridges. (This is not just a social difference, but actually a legal one--software is allowed to disclaim liability in ways that other products legally can't.)
The English in the early 20th Century were quite smug about how their system of primogeniture created a strong, calm, self-confident ruling class prepared by their upbringing to rule. Even the House of Commons tended to be full of near-aristocrats: e.g., Mr. Winston Churchill had the good fortune to be in the now-dominant House of Commons because he was the oldest son of Lord Randolph Churchill who was the second oldest son of the Duke of Marlborough.
- Firstborn siblings spend more of their early years exposed to and learning language from adults versus other children who are only slightly older.
- Similarly, firstborn siblings are more directly exposed to praise and expectations from their parents and other adults, vs the praise and social validation of another slightly older child. Thus they become more oriented to achievements that will impress adults, such as performance in school.
Linguistic research on children has found that the critical period of language learning goes until age 10-12, so any child would have had a lot of exposure to lots of other children and adults in the relevant time period. It’s possible that there is a slight effect on margin, but it seems a bit doubtful.
+1. As the firstborn of 4 and the father of 3, the most obvious distinction to me is that the firstborns are socialized by adults while the younger kids are socialized by siblings. This aspect is consistent with the declining effect when age gaps are large - much older siblings aren't around to socialize younger ones.
Are you sure that older siblings aren’t just more likely to try and please authority figures by performing thankless tasks like filling out user surveys ?
In theory I should be able to figure this out - I included a question "How close did you come to not filling out this survey" to see if this could be used to analyze response bias. I don't feel like actually looking at it right now though.
I've read about first-born superiority, so if I were a first-born, I might want to participate to find out more about my superiority. But, in a Harvard class the professor asked the students to raise their hand if they were first born. Most of the room raised their hands. It was a philosophy class. As a second child, I see the oldest one wanting control with their parents in supportive roles. They have good verbal skills and know what to say to get what they want.
Edit: This is wrong! See André Röhm's comment and my response.
<wrong>
Most people are first-born children, if average family size is not too high. Suppose for illustration that 30% of all non-childless families have one child, 40% have two children, and 30% have three children. Then by simple arithmetic, 30%+20%+10%=60% of these children are first-born. And Harvard students come predominantly from well-off families with relatively low birth rates (see https://www.statista.com/statistics/241530/birth-rate-by-family-income-in-the-us/).
I stumbled over it for a bit, but I am pretty confident you made a slight error here.
The real answer in your example is "50% of children are first-borns".
(Do the math for example for 10 families, and calculate the number of total children)
What you calculated was equivalent to answering "If I pick a random family and then pick one of their children at random, what is the chance to select a first-born?". This underestimates the effects of large families.
Even then, I believe your point still stands that first-born's can be more likely than expected. However, if this blog has such a strong selection effect, would we expect Harvard to have none?
You are absolutely right! Doing it properly, the proportion of first-born children is equal to the the reciprocal of the average number of children in non-childless families. In my example, that would be 1/2, but I don't know what the average is over real-life families, or families with a child at Harvard.
Maybe being older you get lots of opportunities to explain/teach things to a younger sibling, this makes you more reflective and self aware hence more likely to go into higher education get a PhD etc. The decline starting at 8 years might be because at 18 you move out and stop teaching your younger sibling things while they are still quite young and can be taught a lot of things, i.e, less than 13.
Yep, makes them nerds perpetually jealous of their cooler younger siblings, who learned social skills from slightly older other kids rather than adults
Absolutely, plus the corollary which is that younger siblings often don't have to learn things for themselves through experience or the hard work of reflection and self-awareness, so they end up getting less practice in those areas. Also, older siblings will often just do hard things for their younger siblings out of impatience, rather than let them figure it out themselves.
There is teaching, but as a second born, I see the first born wanting to control and get the money first, for college. The first born's verbal skills may get their parents to expect more from them and pay more for them. Though they might be the leader, good leaders hire
talented people. A good leader just knows how to control people, time and has a goal. Brains they can hire. They respect time as they usually pay an hourly wage.
As a younger sibling with a B.S. and an older sibling with a doctorate, I came here to post that exact hypothesis.
Anecdotally, siblings relatively close in age are often playmates, and children whose parents are academically inclined definitely engage in play with the older teaching (bragging about?) what they just learned in school. For me about 2/3 of what I encountered through grade 6 I already had pre-exposure to via this method.
It's funny how school changes to impress parents. I brought home new math and my parents had no idea what it was. Then when I was an adult I saw little kids bring home new math and I was dumbfounded even though I had been a math major for a while in college. The kids always impress their parents with the new things they are learning. Parents then think their kids are so smart and decide that kids should go to college. How do they do it? My sister learned the Dewey Decimal System for finding a library book and her kids learned to use a google search.
My personal hypothesis is that the greater uncertainty involved in raising a child for the first time leads to higher openness to new experiences. I'd guess this can go down a number of different paths in practice, but that cultures situated outside of the mainstream will be disproportionately firstborn as a result.
I've heard plenty of tales of parents being overprotective with their firstborn and then realising that kids aren't actually that fragile and letting the younger ones be more freeform, so I'm not sure the cause you're positing exists in the first place
Exactly, my experience and the one I see as well. New parents insist on strict regimes for everything, everyone over-thought and amusing to more experienced parents.
Get down the line and "good enough" is, indeed, good enough
Best advice I got when I became a parent was from a mom of 3 boys. She said to ask myself “Would I be doing this if it were my third kid?” Saved me a lot of effort so far.
I speak from experience as a firstborn. I have distinct memories from high school of feeling resentful that it felt like I was the guinea pig. I certainly can't speak for all firstborns, though, and don't really know if my experience was common.
But the first born learned to use verbal skills to get what he wanted even when parents had made tough rules. More obstacles presents more practice time.
I wonder if that has changed as parenting standards have increased with this generation.
My older brother experienced much of what you did. Unfortunately, most of the experimentation was the cw/assumptions my father made based upon what worked for his own upbringing - go to Catholic school, play football, etc.
My brother did, and even at times felt compelled to profess he liked some aspects of it. But he was miserable. A complete first-born nerd, he would go on to make good friends in college, become a brilliant surgeon, and win an award from his med school, one of the best in the country, for his healthcare policy work.
He was the most miserable adolescent you ever met. His bad experiences at the hands of his peefs haunted him literally for decades.
My parents observed and, once my brother was able to begin to process it all and speak up, accepted his assessment. As a result he moved to an excellent, small, academically oriented school (without a football team) for high school.
I got the benefit of that environment from the third grade, and more importantly of their open-mindedness when I also was not what one would term a typical small-town Louisiana kid.
As a result I was just a more relaxed and amiable kid, comfortable in my skin. Part of it was younger child peer interactions (vs older child pleasing parents). But a big part was I trusted my parents to listen to me and do what was best for me in a way my brother did not experience, and was accepted by my classmates at the smaller, more academic school from a young age.
God bless man. It all works out, but it doesn't mean it's not tough at times
Totally. The first kid into teenage years is the one who triggers all the unresolved teenage trauma in the parents. I had to muddle through it with little guidance. When my sister came along a) they were worn out from fighting me and b) there was a path and c) they realized some of their strategies didn’t work & updated to better ones.
That first born having to fight for what he wants, verbally makes him skilled at this. I have heard about first borns resenting parents, anger fuels their desire to show their parents a thing or two. They see their parents are new at this. Take advantage when possible. I've known first borns who waited to get divorced until after the parent died, so he could show his parents he was a success and right.
How do you know that "birth order" is not just a proxy for "age"? Maybe people who spent more formative years prior to smart phones are more receptive to long essays of the sort that you write.
Could simply filter for respondents over ~20; There's no reason a 40-year-old reader can't have older siblings, so the effect of younger siblings being too young to be readers would only show up in the youngest readers of the blog.
I remember that Scott said on average, older siblings were only 1 year older than younger siblings (out of the entire pool, obviously, not within the same household) so that is probably not the explanation.
- First borns are part of the "parental teaching structure" of subsequent kids.
- and also competitors, cooperators and imitators. I have a 9 yo and 6 yo and I can tell you they are both forever different, on questions of basic personality/desires because they have a sibling. There are things they do/love/hate because of how their sibling feels about them.
- is there any value to looking at school situations (such as Montessori) that often mix age groups? A class room of all 2nd graders is going to have different "social sibling" effects than one that's 1st, 2nd, 3rd all together.
- and what about the past, when almost all kids were raised more or less in a group - a swarm of cousins of varying ages? Being the first born in a house that only ever has 2 kids is one thing. Being the first born in a generation of cousins probably has different implications.
- did you ask any questions about pets (insert snark about "substitute kids") in the household?
You say snark, but my partner and I often joke, only semi tongue in cheek, that our baby is almost getting a second child experience because the dog still needs attention/walks/etc.
I mean, you're definitely right! At this point with joint dog-human society, you might be able to detect sibling effects on the dog too from having an older/younger "sibling" human. Not sure how to do the conversion to dog years though. ;)
You're only looking at 1/3 to 1/2 the picture. The interaction between the siblings, especially the role assumptions that go on.
Our children are 18 months apart. Just before our second was born, my wife took our daughter to the toy store so she could have a baby doll of her own, something that looked a lot like a real baby. Mom had the daughter give her baby doll a name (Baby Mike) ... OK ... with the thinking mom would have here baby, and our 18 month old daughter would have her own baby to mimic mom, instead of wanting to hold her baby sister.
Great idea, but wrong. Baby Mike went into the toy box to almost never return. Yes, she wanted to hold her baby sister, and we allowed this with close supervision, the older daughter was only 18 months after all.
But what happened was a total bonding, the younger grew up faster, as the protégé of the older, and the older did revert some especially when it came to diaper training. We had read about, and expected this.
I think there was growth and leadership developed in the older child, far vision thinking if you will ... which is pretty much what this forum is about.
The younger child didn't/ doesn't look to the horizon as much as she follows her older sister still in a lot of ways, they're 29 & 31 now.
And yes, I'm the elder of two, my sister is 16 months younger than I.
Your eldest is the first grandchild. Kids can compete to have the first grandchild for favoritism {my observation}. So your oldest has a large audience. Don't want to disappoint.
Whenever this topic comes up, I wonder how only children (no siblings) stack up against firstborns. What percentage of this blog’s readers are only children?
I’m also curious about how many female readers of this blog are only children vs male readers.
I knew that about ACX, but I’m curious how many of the readers are only children, and whether the 10% female readership includes an outsize number of only kids.
In 1976, 11% of American women over 40 had borne only one child, but by 2015 22% were “one-and-done”. I have a strong feeling that only children are more or less firstborns, so likely to be over represented here. I’m wondering if that might be especially true for the women, since anecdotally it seems like we’re outliers in various subtle ways.
Maybe “reading ACX” is more of a proxy for “feels benevolently toward or perceives deriving benefit from interactions with analytical males.” Seeing the application of “that brain” to issues in the world at large is one of the draws of ACX for me. Some people (even with STEM careers etc) prefer to only deal with applications of “that brain” occasionally, or only at work & never outside, etc. They might have or use “that brain” themselves but need/want different social input.
So the father-child relationship might influence this. Most of the research seems to look at mother-child dynamics.
LOL I resemble that remark. I like hanging out with analytical males so much, I married one.
I'm currently mostly a homemaker, so this community has been a really valuable outlet for intellectual discussion. I enjoy using "that brain", and indeed most of my close friends have either been men, or women in STEM careers. I've often been the odd woman/humanities major in the room.
My parents didn't have much of a science background, but my dad was a very "no BS" kind of person, and my mother was quite intensely emotional, which I think is why I always found comfort and refuge in an objective, rational approach to the world. And being an only child, I kind of got away with being as weird as I wanted for a longer time than someone with (especially younger) siblings might have.
In my experience youngest siblings can instantly identify each other. They have been strongly socially conditioned; they were always the cutest, they were always smaller than their siblings, and parents had relaxed relative to the first kid. They're used to losing arguments and having things not go their way (being younger and smaller, not necessarily more or less on track), unless they work disproportionately hard for it.
Some anecdotes:
1. My parents *returned* the gameboy I was given as a birthday present, but my youngest sibling was allowed to have multiple consoles.
2. Although I'm three years older than my sister and she's three years older than our youngest sibling, we all learned to read within two years; I was late, she was on time, and the youngest felt left out and taught themself to read at the age of two. (Those early digital books that highlighted and spoke the word at the same work wonders!) Now, of the three of us, 1 and 3 are the most avid readers. (But 2 got a neuroscience degree, she didn't get off easy!)
3. My dad taught us all to program at the same time; we all started with the same level of competence and quickly developed our own styles. Of us, 1 and 3 are employed as software engineers now; 2 lost interest. (This was also part of a larger experiment on us; in the early 2000s there was a theory that girls didn't enter programming because they didn't have a cohort, which my dad found to be a testable hypothesis, so he not only taught us but also most of my sister's school class. It did briefly keep their interest as a communal activity, but it's not clear it had any long term effect.)
I (a first-born) have also surrounded myself with disproportionately first-born friends, I find we're on the same wavelength. But I know I'm pretty unusual, both in general and among first-borns, so I'm cautious about extrapolating my own experience in that regard.
I’m an only child and all my closest friends were either first borns or oldest siblings, or had a much older sibling who was out of the house by the time we met. And even weirder, all our moms had us when they were 38 years old. I subconsciously gravitated toward a whole set of only children born to mothers exactly the same age as mine. It was pretty unusual to have your first kid at 38 in the early 80s, and we didn’t realize we had that in common until years later. I still think that’s kind of wild.
An explanation of the birth-order effect diminishing with age gaps, which still makes the primary driver of the effect parental attention, could be that the first couple of years of a child's life are the ones that require the most parental attention. A second child who is two years younger than their older sibling will get less parental attention than a second child who is six years younger, because in the first situations, the parents are having to deal with a toddler.
I think I was in your "several biological siblings, no social siblings" group, because of the large gap between my older sisters and me (fourteen years). I've often thought I got the best of both worlds growing up. In terms of parental attention, it was like being an only child, but my parents were still experienced parents, and knew what they were doing because of my older sisters.
The driver might be parental mental clarity rather than parental attention. Attention from a worn-out parent is of a different quality. Five minutes with a clearheaded parent can be more beneficial than hours with a distracted & frustrated one.
Yes, but the attention a toddler get would still be diminished by having an infant sibling. We would have to compare firstborns with short birth year gaps and see whether they do worse than firstborns with long birth year gaps.
> One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower? If it’s about having quality time alone with Mom, someone with a sibling one year younger than themselves only got one year of quality time; someone with a sibling five years younger got five years. But it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one. Either the first year is very important, or I’m missing something.
The lived experience of parenthood makes it pretty obvious why small age gaps have larger effects. The mother of a newborn and a 1 year-old has less attention to devote to the newborn, because the 1 year-old is extremely needy. A mom who read dozens of books aloud daily to the firstborn 6 month-old probably reads zero to the second born at 6 months if there is also a toddler in the house. The newborn gets a lot more of Mom’s attention if the sibling is a 5 year-old able to feed herself, use the toilet herself, play without needing Mom for more than ten minutes at a time, etc.
My theory is that the average intelligence of the other family decreases for subsequent children. The first born interacts with two adults; the second born interacts with two adults and a child.
Hypothesis: "Firstborn" children are recuited as deputy parents when younger siblings come into the family.
I speculate: Consciously, or unconsciously, the oldest feels more like an adult from that point on, and may feel and behave more responsibly, and also may enjoy feeling more "accepted" by their parents into the world of adult society. Maybe younger children never feel this (although families where i.e. the oldest girl ends up with lots of maternal responsibilities are anecdotally common.) Maybe younger childen have a kind of extended childhood vs an "accellerated" childhood for first-borns.
On the same topic, research published ~5 years ago looked at athletic achievment by siblings in US professional sports. (link below...I think, it seems not to be showing up...) They found a HUGE positive effect for YOUNGER siblings, especially the second child in a family. (Note: this study had vastly more male children and brother-brother pairs, for obvious reasnos, but IIRC the effects were just as strong for the few female athletes in their study.)
Several reasons were posited, the two salient ones were:
-- Practice effects: The younger child is often playing with the older, and with other kids several years ahead, this is very tough competition and an intense learning environment.
-- Parental / Family experience: Parents learn how to navigate schools, leagues, coaching, sports-bureaucracies in general, and the younger kids get fast-tracked into the best opportunities.
For me, the absurd number that stood out was this: In US Baseball, 700 (!) pairs of brothers have played in MLB. The younger brothers, collectively, attempted 10x more stolen bases than the older.
I definitely observe more athletic inclination in my younger daughter than in my older - starting with the age of walking, and propensity to climb, and comfort with climbing. I attribute it to two factors, besides innate proclivity: the older one was heavier as a child and maybe that's why she started walking later; the younger one was also on the ground a lot more and held less, because I had two close together - so perhaps she got more practice and therefore started crawling and walking earlier.
On the flip side, the second is less verbal and started talking and singing later, and is less of a communicator than her sister was at that age. This can be attributable to talents but also to having had less focused conversation time from me, while the first one got it from a full-time caregiver while I worked.
I agree. First borns seem to have very good verbal skills. What about the stage effect. The first born needs to put on a good show for parents and grandparents. First borns had to negotiate with parents to get what they wanted and converse with adults more often. More practice verbally for keeping their parents together, working, so they can send them to college.
Having an older brother with marginal Major League potential would probably be the best upbringing possible for a future baseball star. I knew a Cy Young award winning pitcher who was a third son in a much admired athletic family. His nurture was ideal. His father was a successful lawyer and the best Little League baseball coach around: a terrific guy. He had two highly athletic older brothers. His oldest brother had been an All-Southern California second baseman and played at USC, and then was his youngest brother's high school baseball coach. The older brother protected his younger brother's potential. When the athletic director wanted his star pitcher to start on two day's rest in the Southern California semi-finals, his older brother as his coach blocked that at some cost to his own career. "I'm not going to wreck my brother's career to win a game."
Big time sports are so competitive these days that
Relatedly, Seth Stephens-Davidowitz's new book "Don’t Trust Your Gut: Using Data to Get What You Really Want in Life," has a chapter on sports performance. Identical twins are more common in sports like track and basketball that require some innate skill like sprinting fast or being tall and less common in baseball, where success seems more unfated, being determined among pitchers to a large extent by arm health, while hitting a baseball seems like more of a knack than a phenotypic trait like height or speed, if that dichotomy makes any sense.
Thomas Sowell talks about this in "Discrimination and Disparities". Here's what I highlighted in that chapter:
'A study of national merit scholarships, for example, found that, among finalists from five-child families, the first-born was the finalist more often than the other four siblings combined. First-borns were also a majority of the finalists in two-child, three-child, and four-child families. If there is not equality of outcomes among people born to the same parents and raised under the same roof, why should equality of outcomes be expected - or assumed - when conditions are not nearly so comparable?
Such results are a challenge to believers in either heredity or environment, as those terms are conventionally used.
IQ data from Britain, Germany and the United States showed that the average IQ of first-born children was higher than the average IQ of their later-born siblings. Moreover, the average IQ of second-born children as a group was higher than the average IQ of third-born children.
A similar pattern was found among young men given mental tests for military service in the Netherlands. The first-born averaged higher mental test scores than their siblings, and the other siblings likewise averaged higher scores than those born after them. Similar results were found in mental test results for Norwegians. The sample sizes in these studies ranged into the hundreds of thousands."
(...)
"Consider how many things are the same for children born to the same parents and raised under the same roof - race, the family gene pool, economic level, cultural values, educational opportunities, parents' educational and intellectual levels, as well as the family's relatives, neighbors and friends - and yet the difference in birth order along has made a demonstrable difference in outcomes.
Whatever the general advantages or disadvantages the children in a particular family may have, the only obvious advantage that applies only to the first-born, or to an only child, is the undivided attention of the parents during early childhood development. "
Dr. Sapolsky mentions this exact phenomenon in a lecture series on human behavioral biology. The data discounts fetal resource depletion and parental attention. He indicates that the current working hypothesis is that the firstborn is forced into a tutoring or mentorship role.
Hey, I'm one of those edge cases. I'm the oldest of two siblings, but my mother gave a child up for adoption 8 years before I was born. And I'm a classic older child, so one point for some sort of social vs. biological effect.
My guess would be that the difference is variance. Two populations with the same mean will be measured to have the same mean. This is often interpreted as no difference. However, if the standard deviations are different, the tails will look very different. In this situation, that would mean that first born have higher variance. Has anyone looked at the negative end of the spectrum? (As a reader, I’m obviously designating my end of the spectrum as the good side.) what’s the birth order like in prison populations?
>Despite large environmental differences between the areas, we find remarkably consistent results: in families with two or more children, secondborn boys are 20%–40% more likely to be disciplined in school and enter the criminal justice system than are their firstborn male siblings.
Main results (excerpt):
> While we do not find the primary mechanism that results in the higher delinquency outcomes later in life, we do find relatively precise zero results on some of these measures. On others we find decreased direct parental investment in the form of time spent with parents in favor of indirect investment in the form of formal childcare arrangements. Whether and how these differences could affect observed later life gaps is an open research question. This leaves us with parental investments within the home (as opposed to time out of the home and in the labor force) and sibling influences as our leading explanations for the birth order results.
Conclusion (excerpt):
> We find no evidence that second-born children are less healthy, and indeed second-born children appear to be healthier at birth and have lower rates of disability in childhood. We also find no evidence that parents invest less in second-born children’s education. These children attend no-worse schools and are more likely to attend pre-kindergarten. We consider differences in parental attention as a potential contributing factor to the gaps in delinquency across the birth order. Second-born children tend to have less maternal attention than do their older siblings because first-born children experience their mother’s maternity leaves and temporarily reduced labor market participation both following their own births as well as following the birth of the second-born. Therefore, in addition to the fact that first-borns experience undivided attention until the arrival of the second-born, we discovered that the arrival of the second-born child has the potential to extend the early-childhood parental investment in the first-born child
> The firstborn has role models, who are adults. And the second, later-born children have role models who are slightly irrational 2-year-olds, you know, their older siblings. Both the parental investments are different, and the sibling influences probably contribute to these differences we see in labor market and what we find in delinquency. It's just very difficult to separate those two things because they happen at the same time.
In other words, maybe the first-born is a worse role model than the parents.
This is interesting. I am wondering about the effect of parental worsening alcoholism/addiction/domestic violence on children by birth order.
The people I know who were drinking/using with their parents tended to be the younger ones or youngest of several. Possibly the older/oldest get out of the house before it gets too bad but the younger ones are stuck in it (unless divorce or the state separates the family.)
This might influence criminality due to the association with addiction.
>One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower? If it’s about having quality time alone with Mom, someone with a sibling one year younger than themselves only got one year of quality time; someone with a sibling five years younger got five years. But it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one. Either the first year is very important, or I’m missing something.
An older sibling one year older is always doing fresh things, and their one year younger sibling is always just redoing the thing that just happened- there is no novelty, less enthusiasm etc. With a greater age gap, the older sibling naturally ages out of intensive parenting at some point during the younger sibling's development and the younger sibling gets more attention, i.e. older sibling goes off to college when younger sibling is in 7th grade, younger sibling is now effectively an only sibling.
Sounds reasonable to me. My elder brother, god bless him, went off to university when I was still in diapers and here I am. His adolescent parties might have increased my weirdness but that's speculative.
Making my first comment because I have actually thought a lot about this lately. Some anecdotal data to introduce my own theory.
My buddies from school are all very analytical, competent, and successful. Three stand out and they are all firstborn. They also stand out because their younger siblings struggled more and were more rebellious. Add to this general trend a half-exception: my brother and I.
I am a twin. Technically, I'm younger, but I have always been more academic and I was the first one to read, so I was the one who started with a natural advantage. My brother has indeed been "more interested in excelling in areas other than school, like trying to cultivate a special talent that the firstborn [or in this case younger twin] doesn't have." I still remember crying when I realized I wasn't as musical as him and he is now a composer, yet alas, not a frequent reader of ACX.
So here's my theory: older siblings start off with a natural advantage in intelligence. So similar to your second theory (in twins that advantage is decided more randomly because they are otherwise so "identical"). However, younger siblings don't immediately start to differentiate themselves. Instead they are PRESSURED to match the performance of their older siblings. Some of them just can't compete and rebel. They are then led away from traditional marks of success. So even if they could have succeeded in school just as well, they are discouraged from making that their priority because they feel they will never be as good as their older sibling. I still remember the tough fights about grades and music school that my brother and mom had, and I was mentioned way too many times.
Also if there is more distance in age, there is less pressure; their lower performance is more expected since they are so much younger and "eventually they'll catch up." This explains why there is a stronger effect for one-year gaps than five-year gaps. The gaps between my friends and their younger siblings are between 1 and 2. In our clique there are also younger siblings, but they are much further apart in age. These exceptions are the way it SHOULD work: younger siblings aren't constantly pressured into feeling naturally inferior and instead they can just learn from the successes and failures of the older sibling.
Finally, you mentioned that twins are underrepresented among your readers and also receive less attention from their parents. Well my mom gave both of us a LOT of attention as kids, so here I am.
What if the actual effect isn't intelligence, but being antisocial? Could it be that siblings with less time with another kid in the house had more introversion or more non-social pastimes, like reading or computers? I think this is a more direct match to the data. This also predicts that only children should be overrepresented; I imagine this is easy to check. I would also be surprised if there wasn't a question about introversion to compare to, though I don't know if a baseline is easy to find.
I should consider that a marginal influence. Given that "being antisocial" is low conscientiousness with low agreeableness, that's not what I can recognise in ACX readers so far. And families with such traits strongly around probably don't foster academic achievement of any kids, first, second or whatever.
I think they were speaking more in the "colloquial" sense of antisocial which is really more like introversion/awkwardness than clinical anti-social behavior (he mentions introversion in the next sentence which makes me fairly certain of this but I could be wrong).
All speculation based on my own experience as an apparently exceedingly average ACX reader (late 20s, male, white, first born, programmer), but my guess would be that younger children consistently demanding more attention from parents socially conditions older children, especially first borns, to have a figure-it-out/do-it-yourself mentality (higher conscientiousness and industriousness?), which leads to a higher representation in your readership.
It tracks with my own experience that I was more independent and self reliant earlier due to the attention my parents needed to give to my younger siblings, and i think both a high delta in attention % between siblings after a younger sibling is born and the absolute difference in attention % may play a role, in addition to things that other commenters have mentioned like playing 3rd parent.
Interested in others opionions and experiences here, there should be a few other first borns in the comments, does this track for you too?
Every time this comes up I consider commenting, so I guess I'm commenting this time.
A few years ago, my mom (a PhD in developmental psychology) was observing my nephews and said offhand "it's so hard being an oldest child. You have to do everything first."
I asked her about that (being her oldest child) and she pointed out that younger siblings can watch their older siblings, and especially in early childhood, this gives them a lot of information on things like "if I throw a giant fit, what will happen to me?" And "how long can I get away with something before mom and dad notice?" And even "will I grow up? How long will that take? What will happen?"
Oldest siblings (and only children) are pushed to take on new ideas and experiences, that's just how the world works: you start with very limited data and figure it out yourself.
Younger siblings can, if they choose to, observe the results their older siblings got and coast, or at least use that data to limit their options.
So it makes sense for older siblings to be reading blogs about new ideas, technologies, and perspectives. The younger siblings out there will wait to see how it turned out for us before they get into it.
This is the exact story my mom’s siblings tell. My mom was 10 1/2 months (!) older than her sister, with two brothers several years younger. This was back when corporal punishment was common. The girls always said their parents “never disciplined the boys”. But to hear the boys tell it, they watched their older sisters get in trouble, learned what made their parents truly angry, and knew how to stay just inside the line.
I think we were looking at it backwards. We were looking at this through the lens of, "why is the second born child less intelligent or why is the first born child more intelligent". I think it's worth checking statistically to see if a younger sibling makes the older sibling more intelligent. As in, having a younger sibling provides more learning opportunities from a fly on the wall perspective AT a level that is more easily comprehensible than the level that adults usually speak to their children, which is just outside of the child's current abilities. So, the hypotheses are, 1) having a younger sibling provides more easily understood learning opportunities without direct emotional cost of failure AND 2) a setting that perches the elder sibling in a relationship as an outlier with the potential to compound successes. So, we need to know what baseline IQ of only children are and see if the younger children are actually less intelligent than baseline or the older children are in fact made smarter by having a younger sibling.
Re #1, all the oldest children I know maintain the ability to deliver a smackdown on the youngers, in some form. The emotional cost of failure may actually be higher there.
We would need a lot of data to make the comparison valid. Like parental education levels, age of parents at birth, socioeconomic status of household reared in, child's educational level, a valid IQ score, and lots of other things. Then after analyzing and controlling for the confounding variables we could make some further hypotheses. It would be interesting to see how they stack up though. Another interesting idea would be to see if there is a pattern in the personality traits between younger and older siblings, such as openness to experience that could inform us of potential cognitive experiential tendencies.
I like the quote in the first paragraph, "correlate birth order with things." I use to characterize this kind of psycho research as correlating things with other things, happy to find it here. Folks, please remember, correlations are rarely zero in non randomized groups, so this stuff is much less interesting than you think. Moreover, I think I recognize a pattern, that the author of this blog tries to please us by basically telling us, once in a month, how smart we are. Nah, I'm not.
And, of course, the obligatory call for "we need more research" in the end, like a plumber who wants to solve the world's problems with more pipes.
Did you read the post? I'm not doing correlations, and I'm not just finding that some correlation exists, I'm finding that the first to secondborn ratio is about twice what you would expect, in a sample of thousands of people. Recommend re-reading this and if you're still confused I can try to explain specific parts to you.
Could it be reverse causation, that parents who have a especially smart first child are pleased and are more likely to have a second child whose ability reverts to the mean? Did someone do a comparison of all the first-born and second-born, whether they have siblings or not?
> it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one.
The developing brain is particularly sensitive to stress in the first two or three years. Stress exposure modifies the HPA axis to cause a permanent increase in the sensitivity of the stress response. You can see the effect in this graph from (Essex, 2002):
Transitioning from being an only child to being a sibling is an extremely stressful event, so you'd expect it to trigger that effect. Note that although we think of stress reactivity as 'bad', high stress reactivity is likely linked to later 'overachieving', as well as to a higher risk of mental health disorders in later life.
Another factor that may complicate things is childcare -- having a new baby probably affects whether the older one is placed in daycare. Center based daycare in particular is known to substantially raise cortisol levels. Cortisol rises are actually smaller for younger children (cortisol response hasn't settled down yet + lower bioavailability of cortisol) but the measured long-term effects on younger children are larger. So e.g. one causal study of universal childcare expansion of found
> this policy resulted in a rise of anxiety of children exposed to this new program of between 60 percent and 150 percent, and a decline in motor/social skills of between 8 percent and 20 percent.
This is interesting. I’m wondering today about the effects of parental alcoholism/drug abuse/domestic violence on children by birth order.
Since those conditions usually progress and worsen, the older child has more minutes with a stabler parent. The younger one(s) may have the parent who is drunk twice as often/ten times as often and possibly more likely to drink with the child. To the last child’s detriment, in conditions the oldest escapes by already being out of the house.
Unless the parents divorce and the environment improves, in which case the youngers might get a healthier environment.
First child is more likely to have "high functioning" autism than subsequent children (yes, I know the autistic community doesn't like that term, but unless they can come up with a better one, I'll use it in inverted commas). One theory is that this could be due to elevated testosterone levels in the womb (which then decline for later children due to the fact that the poor woman has other children to look after, which tends to reduce testosterone levels). I would be very surprised if this wasn't associated in some way with the higher readership of ACX. Full disclosure: I'm autistic.
Could it be that younger siblings are more likely to mention the blog to their older brother than the other way around. Because when you're the younger one, you're always looking for things that the older one hasn't done before you. The older one doesn't feel the push. This could be debunked if you know how people came to the blog.
Older siblings are by definition older than younger siblings. If older people are more likely to read ACX (which seems pretty plausible) then that's going to be a major confounder.
I think, though I'm having trouble thinking about this clearly, that the entire set of older siblings in the world isn't noticeably older than the entire set of younger siblings in the world, except very weakly since some of the older siblings' would-be younger siblings haven't been born yet, and some of the older siblings have died off while their younger siblings are still alive, neither of which seems relevant to the ACX-reading age demographic.
There is a slight bias. Consider a simple model where all families have exactly two children, at a two-year interval, and everybody lives exactly 70 years. Then nobody gets to be an older sibling until they're two years old, so the average age of older siblings is 36; but the average age of younger siblings is 35. However, the average age of older siblings over two years old is the same as the average age of younger siblings over two years old. So you're good, as long as none of your respondents was less than two years old.
Isn't there also a change as birth rate increases or decreases? As in if birth rate is decreasing, there is a higher percentage of firstborns among younger generations?
Here's how I'm thinking about this. There is some median age at which a person is likely to discover/become interested in ACX. To take one example at random, I started reading ACX when I was about 29, so for the sake of example, let's call that the "cutoff age". The mean ACX reader is 33 (very close to my own age). All younger siblings who are 33 have older siblings who are also above the cutoff and so would be equally likely included in the sample of ACX readers, but many older siblings who are 33 will have younger siblings who are BELOW the cutoff age and so would be excluded from the sample simply by virtue of being too young to "age in".
You'll get SOME effect from this with only two assumptions: there's a de-facto age-in cutoff for ACX readership, and ACX readership is heavily concentrated close to that cutoff, which I think are both reasonable assumptions. I don't know what the R-squared of this effect is but I expect it to be non-zero, and it might be big enough that the question ceases to be interesting.
Here's another example to illustrate the concept: What percentage of retired Americans are the youngest sibling in their family? I have no idea but I'm willing to bet that it's disproportionately high, and that has nothing to do with birth order making you more likely to retire.
The effect from older siblings whose younger siblings are too young to read ACX is exactly counteracted by the effect from younger siblings whose older siblings are too old.
There's always an age-out: if nothing else, there's death.
Note that I'm not saying that ACX readers regularly have older siblings that read ACX and then die. It's enough for the probability of reading ACX to begin with falls off with age until it hits 0. It must, because the probability of someone reading ACX when they're 1000 years old is 0.
I didn't say no age-out, I said EQUIVALENT age-out. Put the middle of the bell curve at 33. At 63, you're probably only slightly less likely to read ACX, but at 3 you can't read at all.
Assuming that older and younger siblings are no more or less likely to die at any age than each other, they should be equally represented at all ages. For people under 25 or so, some older siblings may be undetected older siblings, while no younger siblings are undetected, but if you look at currently living retired people, there should be precisely the same number of people who are the older of two siblings as who are the younger of two siblings (if we ignore whether the other sibling is currently alive or retired).
I'm assuming a stable population structure, so that the number of first children born every year is the same, and the number of second children born every year is the same, and the number of third children born every year is the same, and so on. In families that have two children ever, there must be the same number of first children as second children ever. Given the stability of the broader population, this means that the number of (first children in families that will eventually have a total of two children) born any year should be the same as the number of (second children in families that will eventually have a total of two children) born in any year. (The difference in the number of first children born in any year and the number of second children born in any year is the difference in the number of families that eventually have a total of one child and the number of families that eventually have more than one child.)
If first and second children are equally likely to die at any given age, then my first sentence follows.
If a population is steadily growing at a 2% annual rate, that could mess things up (though it's not immediately obvious to me whether that will increase first children relative to second children or vice versa - though I think the size of the effect will just be 1.02 raised to the power of the average age difference between two siblings). If there are specific years in which families were more or less likely to have children (such as the reduction in childbirth during World War II and the covid pandemic, and the boom in childbirth after World War II) then that will produce an effect on birth orders whose direction may depend on precisely how many years ago that event was.
To whatever degree older siblings are older across the general population, we should expect it to increase the larger the age gap between siblings is, while the readership effect increases the smaller the age gap between siblings is.
I wonder if it is more subtle than just quantity of attention - it's quite exciting doing things for the first time with your oldest, teaching them things etc. but when you get to younger siblings, you feel you have already done whatever it is, and it is slightly boring so you don't bother quite as much - the novelty value has gone.
Even assuming an implausibly hard selection effect where all ACX readers have IQs and openness of at least 3SD above the mean, I can't get such an extreme skew towards first-borns. 64%, not 72%.
But it can certainly explain part of it. The first-born effects of IQ and openness are known, and known to be small (roughly 1/10th of an SD) but they show up more in the tails. If 1/10th is an underestimate (plausible for a few reasons), maybe we can go to 72%, but it's still an implausibly hard selection effect.
But what's the mechanism behind the IQ and openness effects? They don't show up in every culture (Botzet et al. 2021). The study major effects (Barclay & Myrskylä 2016) show up in Sweden, or I would have considered that perhaps in the US with the high cost of tertiary education, first borns are more likely to have their parents be able to pay for it.
> n <- 1e8
> bo <- rep(0:1, each = n/2)
> ops <- rnorm(n, 99, 14.98) + bo * 1.5
> iq <- 99 + 0.3 * (ops-100) + 0.95 * rnorm(n, 0, 14.98) + bo * 1.5
8000 people took the survey. If they're selected out of a worldwide population of at least 250 million English speaking adults, that selection is 4 SD above the mean in whatever traits make people read and fill out surveys on ACX.
If those people are 3 SD above the mean on the traits affected by birth order(IQ, openness etc), that would imply a correlation of 0.75 with the traits that make you an ACX-survey-filler-outer(IQ, openness, conscientiousness?). Sounds reasonable to me.
By the way, when you say 1/10th of an SD, is that an average difference between siblings, or an average between first-born and second-born siblings? From Sandra Black's Swedish study, the difference between the first-born and second-born was the largest(illustration: https://emilkirkegaard.dk/en/wp-content/uploads/black1.jpg), closer to 2/10th of an SD in cognitive ability I believe.
Also, if you're 1/10th SD above average on IQ, and 1/10th SD above average on "personality", then you're more than 1/10th above average on a composite of those traits.
There are several samples in the study though and she gave 10% as the approximate overall effect. But yeah, could be a bit higher. Barclay also has 2.3 IQ points in a very large sample. It still doesn't get us to 72%, but it could explain part. I think Scott has IQ and openness data. I doubt >3SD selection is what he finds, if he has tests with norm data available (easy for SAT, maybe not for openness).
Let's say ACX survey takers are at least 4 SD above the mean on a composite "ACX survey taker"-trait as previously calculated. For older siblings to make up 72% of the people 4 SD above the mean in a trait would require about a 0.22 SD advantage in that trait.
If that trait is a composite of IQ and openness(or a composite of IQ and many relevant personality traits), then it would only require older siblings to be 0.16 SD(2.4 IQ points) above the mean in each of those two traits, assuming they both matter equally.
Maybe you know enough about birth order personality effects to rule out such an advantage in openness or any ACX-relevant personality composite, but otherwise it seems like decent explanation for the 72% older siblings to me.
> I additionally tried to compare two different types of social firstbornness - one where no older siblings lived in the house when you were growing up, and one where your parents had never parented another child. There weren’t many people discordant on these two measures (29 vs. 20 respectively), but for what it’s worth, the ratio was in favor of the first type.
I can't tell what this means. As far as I understand the terminology, the set of "people discordant on these two measures" unambiguously refers to every subject whose answers to question (1) and question (2) do not match. But that is a single set of people which cannot have population 29 and population 20. Who's in the group of 29? Who's in the group of 20?
> So for example, since the older sibling will always be smarter than the younger when they’re both young children
This claim can't pass a laugh test. How long did it take your little brother to be better than you at playing piano?
Great post, but I’ve got 3 kids and my immediate n=1 explanation didn’t really fit with your 2 suggestions. Seems to me it’s explained by the relationship dynamics of having a sibling but is NOT really to do with differentiation from each other. Young children who are 2nd siblings and relatively close in age to no. 1 seem to get a huge proportion of their social and intellectual development from the older sibling, regardless of gender and differentiation. I think that that close bond and dynamic reduces their drive to seek new sources of information (such as ACT) because the older sibling has such a strong influence in shaping their frameworks for viewing the world - even when they actively/ innately differentiate from the older sibling’s frameworks. In addition, the older sibling becomes accustomed to socializing the younger into their (older sibling’s) developing discourse. They are likely to feel rewarded/ fulfilled for this from the younger sibling’s receptiveness to taking in the info from them. This creates in aggregate a lasting disposition to seek new sources of info. Again, it’s easy to see that this may only play out within narrower samples, such as your readership, or with specific classes of info, but be lost at the general population/ broad context level.
My observation: The first child learns to be a boss by bossing around their parents first.
New parents want to be good parents and attend to their child, so they listen for what the child wants. They have time, attention and no experience at parenting at this point.
That first child can end up running the parents lives. And with that experience, any later children will be less experienced at being the boss and the parents will be more experiences at rearing children. But at the same time, the first child has already learned to dominate and doesn't like giving up that power. The second child might rebel and try to take a different path in opposition to the power of the older sibling, but a third or fourth child has to fit in some how. After all, the decision-makers, oldest child, parents and second sibling will make the rules.
Anyone care to comment on their observations of first child being the boss of the family?
My eldest son never seemed to want to be the boss of anyone. The second has been tougher but still very agreeable. The third can take responsibility alright. All wonderful guys.
As the technically ‘middle’ child of triplets (ten minute age gap solely due to birth weight) this birth order research always seemed a bit silly to me, but I suppose that’s mostly because of my personal unfamiliarity with the phenomenon of sibling age gaps.
From what I remember (being the 1st, and completing fitting the findings: I read ACT, I am in STEM while my brother choose a more artistic path), we should not look at parent investment or anything parent related (which fit well with parenting generally having little effect), but at direct relation between siblings. We formed a 2-member gang with my brother, with the eldest (me) the natural and not challengeable (at least until we were both past 17) leader. I think it fits my model of genetic>peer>parent in term of relative influence on every psychometric, when peers are siblings and later friends/schoolmates. Your siblings are part of your peers, the most important or even only one before 6yo...
The only thing I find quite strange in the data is that I expected a huge difference between same sex and opposite sex siblings: The brother sister dynamic is very different than between brothers (among sisters I do not know because I have no direct experience nor first hand observation among my friend's families)
I think the differences between same-sex and opposite-sex sibling sets are much more minor in the early / preschool years, which are probably more formative.
good point. I do not have any sister, and among my friends I have observed the brother-sister dynamic only for older siblings, at 12y+ I would say....But now that my friends and I are at the parent age, for pre-school brother/sister, it's indeed more similar. This early they already have very different male/female interests but it's the oldest that is the leader, boy or girl. Still, given the diverging interests, I would have expected a larger difference....except if the key moment is really when the younger child have almost zero non-famlily interraction (before 3yo).
It's often said that all of the original seven Mercury astronauts were first borns or only children and 14 of the next 16 American men into space were the same. But I don't see a link to a study.
As a Catholic Baby Boomer, my being a (rare) only child was a big deal when I was a kid in the 1960s. My friends assumed I got more presents on my birthday than they did (which I probably did). Adults were always telling me I was emotionally deprived by not having any siblings (which I probably was)
Now that only children are common, I never about them anymore.
Maybe for many younger siblings, if they do nerdy things at home, they get teased by their older sibling. And then "not being a nerd" might become part of their identity. But IQ other major life stats stay the same. This hypothesis would weakly predict that male dancers are much more likely to be older siblings.
Except the phenomenon being explained is that older siblings are nerdier on average. Why would nerdier older siblings tease their younger siblings for being nerdy?
Say, for example, 20% of older siblings are nerdy compared to 5% of younger siblings. So up to 80% of the time, a younger sibling would get teased for nerdiness. Whereas if a younger sibling tries to tease an older sibling, the older sibling rolls his/her eyes.
It seems kind of strange that the focus is all on intelligence and academic achievement. The effect of birth order on readership of this blog (71/29) seems to be much stronger than for physics laureates (60/40) . While we might like to think that reading ACT is as good a proxy of intelligence as a physics Nobel, it suggests to me that it's a more specific personality trait that first-borns tend to have that correlates with attraction to a weird rationalist blog.
I don't think so, dumb as I am. Still I like the culture here. Wouldn't care to join MENSA and probably wouldn't qualify any more. Still unsure about joining any club that would have me, like Groucho Marx.
An interesting birth-order sports anecdote is Fernando Valenzuela, the Los Angeles Dodgers baseball pitcher who caused a sensation in the early 1980s. He was the youngest in a family of 12 in Mexico. He had one of the dumpier bodies you ever saw on a famous athlete, but was a baseball genius.
His older brothers were ardent baseball players too, but they had to go to work when still young. But Fernando was the adored baby of the family and was allowed to do nothing but play ball.
A possible overlooked confounder here is age. I'm 19 the oldest of 4. My younger siblings aren't at the age where they'd understand ACX.
As for your average 33 year old ACX reader you can suggest that many of your readers came on board in the Golden age of blogging ~10 years ago when their siblings were too young to come on board.
Interesting point. Previous attempts here to work out the age effect have assumed a uniform population size. In reality, global population is increasing, leading to a greater likelihood of someone being "not old enough" than someone being "too old". But if it's a subpopulation that's both rapidly growing and just coming of age, this could have a big effect.
*edit* Never mind. There would have been firstborns too old to join the subpopulation.
Is there some "recommended" way of sharing analyses? I'm curious about the the bio/social split, if I find something interesting I'd like to share.
I'm looking into it because I was a bit confused by Bucky's part about the biological vs social effects. If I get it right, the point of their selection (bio > 0, social = 0) is to filter people who had biological siblings at some point, but currently have none? I get that this would "isolate" the purely biological effects, but it also seems to introduce all kinds of other biases (it's not really representative of the general population) and additionally it doesn't even mean that there were no social siblings *at a previous time* in which it could have had an influence.
(btw the link to the CSV file in the old blog seems to be broken, excel file is fine)
Of my three kids, each 21 months apart, the younger two strongly tend to do what their older siblings are doing. They learned early on that to imitate is usually a good choice, so they do it a lot and it serves them well. The oldest imitates adults of course, but not nearly as automatically, because she knows many things we do she cannot or is not allowed to do. What she does do, however, is explain things to her younger siblings and give them instructions. That's what she got from us and it's harder than imitation but I think she has learned to think in that way.
None of them are in school yet, but I expect the oldest will find explanation-heavy subjects like math and physics slightly more intuitive than imitation-heavy subjects like music and physical education, and maybe her younger siblings will tend to go the other way.
Of course the ratsphere is super into explanation and I would argue it grossly neglects imitation. When we try to persuade, we try to craft excellent explanations, rather than build shiny role models to champion beliefs we want others to share. But much, arguably most, of human learning in the general population happens through imitation. Especially on ethical matters.
Could sleep disturbance in infancy be an explanation? When you are the firstborn, your parents try very hard to avoid waking you up, and you enjoy uninterrupted sleep. When you have a toddler sibling, you get waken up all the time. If uninterrupted sleep is important for infant brain development, it would explain why the effect disappear as age gap increase (a 5 year old can keep quiet, a 2 year old can't), and it would explain the twins (twins wake each other up all the time).
Maybe - I have thought one of the strongest determiners of infant sleep is whether they are hungry (the secondary one being when the baby wets its diaper and wakes itself up.) In the first few months when the baby has to eat/nurse/be fed every 2-4 hours, it’s challenging to get any sleep and so the “don’t wake the baby” goal is so the parents can a) sleep themselves b) ever do anything other than baby care.
There might be a sweet spot of maximizing sleep and nutrition both, leading to best brain development. Babies who are difficult to calm do have a higher incidence of bipolar when older - maybe they don’t get enough sleep-based neural pruning (whatever that’s called).
Yeah, that is an implication and I should have thought of that. I don't see any discussion about only children in either post, in part because of controls (only children would tend to have more educated parents, so they could be overrepresented here even if the hypothesis is correct) and because the % of only children has increased over time (and is different in different countries).
Could there be some selection effect (at least for ACX readers)? Readership is smart and in an age range such that a smart older bro also reads ACX but the smart younger bro does cooler other stuff(?) Accelerating change of internet, older generations more similar than newer, I dunno.
I guess I'm an aberration. I wasn't around for Slate Star Codex, but I read this blog. I am the third of three siblings in order of birth. I know for certain that one of the others doesn't read this blog because he's dead, and I doubt the other one does because he's not a big blog reader and mostly not interested in even the wide variety of subject matter covered here (if you start covering the NFL and military matters a lot, he might notice).
Eh, I'm the 2nd of 2 and I don't think my brother reads ACX, despite being smarter than me. "Exception" might be a better word than aberration.
Side note, I wish Scott had included families of 1 child in his analysis. Maybe that would have thrown things off or been more complex; it's just that I'm curious. Rumor tells me only children are "like oldest children only more so," and I'd really like to know how likely this is to be true, since I have an only child.
I think the reason he didn't is that he only has data from people who do read SSC.
Though I suppose you could compare "portion of the general population who are only children." with "portion of the SSC/ACX survey respondents who are only children." (maybe controlling a bit for age or other factors?)
I think that Caplan and others tend to overstate the results of the research he presents. I don't remember the effect sizes of the top of my head, but I think his data indicated that something like 1 SD "better" parenting led to 2-3 point increases in IQ. This is a much more modest effect than most people's intuition, but still significant, especially for tail outcomes.
The social sibling effect could easily raise the IQ of first borns by a couple points, which is going to lead to noticeably skewed ratios for the tails. If, among well educated parents, the average 1st-born IQ is 114 and 2nd-born is 110, then among IQ 140+ individuals who are 1st or 2nd born, 65% will be 1st born.
At least for Nobels, etc., I'm going to blindly guess it's the differentiation thing.
I know both me and my (younger) brother were absolutely determined we weren't going to do STEM related stuff because our dad was an accomplished programmer and adopting his profession in a world of infinite choice felt somehow medieval.
But it turns out genetics is strong. We're both garbage in our chosen careers because young folks stink at choosing careers. But we've both managed to fall into that kind of work later in life.
In a family that was more traditional (as I gather traditionally successful folks' families tend to be), I would have been pressured into my dad's profession (and inherited his business contacts) while my brother would have had to work something else out.
Do I think that's a recipe for general success in a typical family? Force your kid to do what you do? Absolutely not.
But when talking about people who perform at the very top of their fields, probably genetics and nurture both have to be moving in the same direction. And really you can only do that kind of intensive training with one kid, and probably you pick the first one.
It's a tough course to steer. Forcing children into anything isn't going to go well, but seeing that Tommy has talents for X and ushering him along the path towards a career in X is different.
There is so much cultural pressure built up around the eldest son to be the bearer of the family heritage, even if that is relieved a lot in modern Western society, that it's hard to say. Take Leo Varadkar, who is an Irish politician and in government at present. Father a doctor, mother a nurse. Two older sisters - doctors. He's the third child and only son. Trained and qualified as a doctor, then went into politics.
Also a new paper about IQ & birth order finds effect even controlling for family size (which is important because it was said family size-IQ relationship produces the IQ-BO statistical artefact):
There's a plausible-sounding medical explanation for Ray Blanchard's finding of why younger brothers tend to be modest more likely to be gay than older brothers involving repeated exposure to male hormones in fetuses affecting mothers' gestational environment.
I'm wondering whether the apparent effectiveness of the English system of primogeniture -- the oldest son will inherit the lands and the huge house and the seat in the House of Lords while the younger sons will go into law, church, Navy or Army depending on their specific characteristics -- might be tied into this. Perhaps oldest sons tended to be less variable than younger sons and thus made slightly better heirs and landowners?
Gives tables from work carried out by an E J Finnochio, that the birth order (or rank) matters for the racing success of the foal. And that the age of the dam is less important.
It seems like there is an assumption being smuggled in here, namely that “reading SSC is correlated more with intelligence than some other trait.”
What if that other trait is, say, conscientiousness, or being thing-vs-people oriented?
Like, what if older siblings are less likely to be as people oriented because they didn’t have someone a few years older than them as one of the most interesting, salient features of their environment?
I’d love to see if the “first borns are overweighted” thing is true even if you filter out people who put themselves on the autism spectrum. That’s the approach I’d be taking - I’d try and find subsets of the data where the trend dissappears.
This is only slightly related, but... Do first-borns tend to partner with first-borns? This is a trend I've noticed in my family and wondered about before. If there is some set of characteristics associated with being the first-born, it could be that people with a lot of those might be attracted to other people with a lot of those as well. This could explain not only my observation but also why these people clustered together as this blog's community.
With infinite resources, we could also survey a whole university, say, and see if people's chosen major has predictive power over their birth order. I think someone already mentioned this, but I get the feeling first-borns are more likely to be pressured into studying something traditional and "safe" than their younger siblings.
Nowadays nearly half of people are first-borns. To check that up, one has to look at times when there were 11th borns. I don't see a trend of first-born-attraction in my genealogy but that is much too little data.
What about the likelihood of finding only children in your sample? If hypothesis 1 is true, we should observe more only children when controlling for the relevant variables (that is, considering that only children are possibly more likely to come from unmarried couples, short marriages, etc).
Some people commented on the possibility of a "mentoring effect" for first-born children. If only children aren't more likely to appear in the sample, then that hypothesis could be more likely.
I also think about other variables that are not related to intelligence. Like some readers mentioned, the likelihood of the older sibling finding more introspective hobbies. I also consider the likelihood of the younger sibling learning how to be more "charming" and social in order to get more attention and differentiate himself from the always older and more intelligent sibling.
"One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower? If it’s about having quality time alone with Mom, someone with a sibling one year younger than themselves only got one year of quality time; someone with a sibling five years younger got five years. But it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one. Either the first year is very important, or I’m missing something."
Babies and toddlers are higher-maintenance. If the older sibling is already seven or eight when a new baby arrives, the baby obviously has more pressing needs, and the parents will in fact switch tracks to doting on the baby, possibly growing somewhat neglectful of the older sibling. Also, a much older sibling is old enough to, themself, help care for the baby, which will help smooth things over; a two-year-old is pretty useless (and sometimes actively harmful) around a newborn.
Yes, this. Plus if the older sibling is old enough to be at school, then the baby is effectively a firstborn for six hours a day - both in the positive sense that they get more 1:1 parental attention and in the negative sense that they don't have a close peer to play with and imitate.
"a two-year-old is pretty useless (and sometimes actively harmful) around a newborn."
Aha, yeah. I nearly gave my mother a heart attack years back, my younger sister was born when I was two, so when she was about six months or so (EDIT: maybe she was a year old, so I would have been three) my mother put her out in the garden in the pram. She started crying, so like a good Big Sister I took her out of the pram and carried her indoors. She was slipping out of my grasp but I managed to grab her like a parcel, more or less. When my mother saw me proudly carrying her in (with a shaky grasp around her middle), she lunged to take her from me 😁
I was five when my younger brother was born, so I was more helpful and less dangerous then!
My explanation is that first children are required to take the lead on a whole host of situations where the siblings are involved. By taking the lead, out of necessity more often than not, the other children are relieved of that duty. That trains the younger children to be followers and the older children to be leaders. This explains why children a few years older create a stronger tendency, and also why after seven years it drops off - too little difference makes it less obvious who is in charge, while too much difference reduces interactions.
Why does this affect ACX readership? I think this blog interests people who are trying to figure out the world and make decisions about practical and moral effects. For someone who thinks that's important, there's a clear reason to follow the blog. For someone trained to let others do that work, then there's much less reason to follow a blog like this.
I’m an older sibling but I can’t imagine my younger brother, who has a higher IQ, earns more and is generally more successful, taking an interest in this blog. I tend to experiment a little more, have wider interests and deep dive into obscurity whereas he does the normal stuff very well
Wild. The one trait psychologists agree is known to be causally influenced by birth order (male homosexuality) is the one most accepted to be biologically and not socially caused?
They looked for the birth order effect in boys with older adoptive and step brothers, and did not find it. That is why it's accepted as 'biologically' caused. However, a recent study challenged the birth order effect as a statistical artefact, so it looks like there's no nurture effect either.
" Firstborns get more quality time with their parents during the first few years of childhood."
I am puzzled. You seem to have an assumption that reading SSC makes firstborns better in some sense. But maybe it is something not-so-glorious that happens because the firstborns get more undivided attention of their parents: I can imagine the undivided attention makes them prone to navel-gazing and overestimating the extent their personal subjective experience and thoughts in general are super special and important and worth of loudly explaining to everyone around? Or, in other words, increased interest in philosophy (edit, and lets be realistic, strong political opinions)
The effect would be then naturally strongest in people who were the only child in the family. Eldest sibling has to learn to share when the siblings are born.
Does the data show there are more SSC readers who had no social siblings, compared to overall amount of them in the respective age cohorts?
What we need to do is link up the birth order data with the (self-reported) mental illness/psychological problems data and see how that stacks. I think many of us are somewhere on the autism spectrum or thereabouts, so niche interests, obsessiveness, and wanting to talk about our pet subjects at length and in detail all go along with that.
Plonk us down in a group of the like-minded who will pay attention to what we're saying, argue back, and talk about *their* pet subjects at length and in detail, and who won't be "don't you have any *normal* hobbies like going out to bars to have fun, pop music, and movies?", and we have our little acre of paradise right here.
Eldest sibling does have to learn to share but eldest sibling also often gets landed with the caretaker/teacher role, e.g. "help Jimmy with his maths homework; did Susie change her dress?; set the table for tea and call your siblings in" etc. so being bossy and lecturing are habits you pick up.
I'm really surprised that this (IMO very weak) conjecture is getting a pass:
"Given that readers of this blog are highly-educated (about 37% have masters or PhDs) and mostly in STEM (41% programmers of some sort), plausibly birth order affects something about intelligence, education, or STEM orientation"
I didn't take the survey. Did you ask if the siblings have advanced degrees or work in stem? Have you directly addressed the possibility that older siblings might just enjoy reading blogs more? Or as another user points out, be inclined to take surveys more? Or spend time on using the internet more? Or any number if other factors?
I guess I am the only woman and mom here and oldest daughter of a line of oldest daughters, and I had to smile a little because I never bullied my younger siblings: in fact in many times I was their mother and nurturer when I had to babysit for them. Now my sons.. well I see what you are talking about: though i always encourage them to get along: it was the second son who was the bully if any of that went on.. well gotta go.. yes. that is just our little story: circumstances vary.. have doctor's appts. today.
There may be as many as several of us women on here! I don't know about how many mothers, though.
Again, it probably is that girls get steered (pushed into?) the mothering role, also depending on how many younger children; certainly, for our 5+ families, the division of labour with the eldest daughter taking up the slack for the mother is going to be there. Boys may have more social/cultural licence when it comes to 'rough and tumble' and 'fighting your corner' which can slide over the line into bullying.
I think the eldest tend to invoke their delegated authority over the younger ones, in most cases, and if that fails fall back on "I'm telling Mom and Dad", not so much as going for bullying. I can see younger (especially middle) kids bullying because they don't have the same quasi-parental status so to make their younger sibs fall into line, they have to bully.
I think I have being an only child to thank for a lot of my personal weirdness. But I think the domestic thing is hardwired; I did most of the chores when I had female roommates, probably more than I do living with my husband. I think what I get while cooking and cleaning is kind of a flow state. Whoever gets their groove on doing chores will probably end up the homemaker in a household. Childcare is just kind of an extension of that, at least so far (I have little kids).
Anecdotal, but this makes complete sense when it comes to my childhood. Younger of 2, both pretty intelligent.
When at a young age my brother discovered e.g. that you can use strategy in games, he found that it let him win every game against me, so he focused on that discovery, and soon even won some games against my parents.
When at a young age I discovered that I could use strategy at games I found out that it does not matter, I never won a game not entirely on chance no matter what I did (because my brother of course by then was way better at strategy). So I stopped playing Risk, or Chess, or any games like that after a while, because what fun is it if you never win?
Sports was similar.
So my brother learned young that if you dedicate yourself to something, you can excel. Tends to produce a strong work ethic.
I learned young that what I do doesn't really change how things turn out.
You may not be surprised that his academic achievements surpass mine...
Wait, we've got to supplement this one, as we have actual data/knowledge here that goes beyond anecdote.
In sports - at least in basketball where it has been most studied - we know that (i) younger siblings do better and (ii) a factor in a talented kid developing into a pro-level talent is them playing a couple of levels up throughout their youth, with kids a couple of years older than them (something younger siblings can do naturally, obviously).
Essentially, when you're talented it's easy to stagnate, to rely on your physical advantages and fail to develop the finer points of your game. This is especially so with guard skills (three point shooting being a classic David vs Goliath strategy) that you don't need to bother with when you can just overwhelm your opponents inside.
Applied more broadly, older siblings crushing younger, inferior competition shouldn't make them great at those activities - there's obviously a lot of sips between the cup and the lip in your brother's story, in going from beating his kid younger sibling at strategy to beating his parents.
Whether younger siblings develop effective David strategies or just keep getting pummeled and lose interest may depend on the activity. But there's at least some documented advantage for long-term high-level skill development for younger siblings who are able to hang with their older siblings and compete
There probably is supporting evidence to that in competitive martial arts. Muhammad Ali had an older sibling who boxed AFAIK. And among fighters I know, in families with known talent, talented young siblings seem to fare better. They have to struggle, but their brothers won't crush them, nobody's crushing them if they have big fighter brothers and they can develop well.
From my experience as a South Asian/East Indian immigrant (not necessarily high-income) is that among my first cousins on both sides, the oldest of the family is always the most 'traditionally successful' in levels of education, type of field, and income. This is regardless of gender or varying family income or significant life events.
Culturally, there's an idea that the oldest needs to make it for the family and the pressure is intense to do really well in school and everything else. I am not American either, so I can't imagine how much more formalized that gauntlet is with US-style admissions, etc. Perhaps there's something similar for Western families but less explicit and less tear-inducing.
in the developmental psych literature, does parental pressure itself do better than parental investment in the form of Advanced Einstein baby toys or reading books? Its hard to disentangle the two, of course both nature and nurture-wise.
I often think of this kid I tutored years ago. Son of Korean immigrants, oldest of three boys. He wanted to ace the SAT, but he was under so much pressure to excel and set a good example for his brothers that he’d totally lock up when asked to write anything. He said once the clock started it was like his mind went blank, and he could only come up with 2-3 sentences that felt worthy before time ran out.
I tried breaking a good essay down into small parts and asking him to think of them in order when he got stuck. We used little tricks like diagramming an essay directly on the writing prompt. Then we did a kind of timed writing exposure therapy where I gave him silly fun prompts and 10, then 5, then 2 minutes on a stopwatch to see how much he could put down on paper. It sort of worked; he went from writing almost nothing in 30 minutes to filling a page. I recall he did OK on the SAT if not spectacular.
I think some consideration to the ideas outlined in "Deep Nutrition" a book by Dr. Cate Shanahan which talks a great deal about the findings made by Dr. Weston Price should be included. The idea is that nutrition plays an enormous role in physical health and intelligence. Their assertion is that inadequate birth spacing (less than the 4 years they consider ideal) means that the mother is nutritionally deficient which is then passed on to the child creating less than ideal conditions for proper growth and maturation. I am by no means an expert, but I think this merits discussion.
It's fascinating to see this effect in the data - it's *quite* clear in my own life. I'm the oldest, a lifelong nerd. One of my brothers is two years younger and always rejected academic stuff - not necessarily less smart, just much less interested in it. Then my other brother is several years younger than both of us, and pretty nerdy. Point for point reflective of what we see in this data.
I think nerdiness has more to do with it than intelligence or education. I'm about as smart as my sister, and we're equally well educated, but I have a hard time imagining her enjoying this blog. (I'm the younger one, though.)
A major difference that I don't see in the comments below is that first-borns with reasonably small age gaps are always a bit further along than their siblings. If you're a parent and you want to teach something, it is very likely the first-born who is most able to learn it. If an opportunity comes up and you're trying to figure out which of your children is best positioned to take it, that as well is most likely to be the first-born.
"Given that readers of this blog are highly-educated (about 37% have masters or PhDs) and mostly in STEM (41% programmers of some sort), plausibly birth order affects something about intelligence, education, or STEM orientation"
Well, if I didn't have Imposter Syndrome beforehand, I do now! Should I bask in the reflected radiance from the smart and successful, or ask 'what the hell am I doing here?' 😁
I have always relied on the kindness of strangers 😁
Honestly, though, when I look around at the intelligent (and handsome, talented, and modest of course) company I'm keeping, I go "how the heck did I finagle my way in here?"
Birth order effects - well, I think there is a difference between how the eldest and the rest of the siblings are treated. For the eldest, it's the firstborn child, parents generally are not experienced, and generally put a lot of effort in. This results in both good and bad attention; you do have your parents able to spend a lot of time with you and work with you on everything from going for walks to teaching you to read.
It also means, however, panicking about minor things (every kid gets colds and sniffles and all sorts of illnesses, inexperienced parents worry that this could be something major), and a lot of attention on how you behave, how you do in school, etc. because this reflects on them and their style of parenting - they're as afraid of being judged as bad or neglectful parents as you are of being judged a lazy or ungrateful child.
As you get older, that advantage gap over your younger siblings does remain, but it also means that (1) the more siblings you have, the more relaxed your parents get, so there really are fights over "Mom and Dad never let *me* do that!" (2) you do get responsbility as "you're the older one, you must look after/help your little sibling(s)" (3) when you're very young and attention gets split with new baby/younger siblings, yeah you do get jealous because now you're no longer the sole apple of their eyes.
I don't know about carving out non-competing niches for attention, maybe it is so; from my own experience, being interested in 'intellectual' (for want of a better word) pursuits was how I bonded with my father. My siblings went different paths; my younger sister was more traditionally 'girly' and bonded with my mother; my younger brother was smart but could not wait to leave school and go into work, and my youngest brother (the only one of us with a college education) ended up as a high school science teacher.
So, maybe this is how we all picked different ways to not be in each other's shadow? Who knows?
(I don't think there's much to 'worry' about in terms of not having a Masters or PhD – I don't have one! School's bullshit! This could be, of course, self-serving ego protection!)
"This was surprising, because at the time lots of studies had shown there weren’t really birth order effects (that is, firstborn siblings had no major personality differences compared to laterborns)"
What were those studies? Do they seem to have been decent work?
The question that I'm really interested in: where are the younger siblings filling out surveys? Is there another blogger (or vlogger) that has that audience? I'd like to find them.
Someone suggested that it's totally possible that there's no effect of birth order on blog readership, but the effect is entirely of birth order on propensity to fill out surveys.
I would assume if it were firstborns are significantly more likely to fill out surveys at all, that would show up in the decades of voluntary psych research already and we wouldn't have this establishment bias that there isn't birth order effect.
Plus if we could identify even one villainous hive of secondborn survey-fillers that would be pretty good evidence and fun to investigate.
So: anyone here have a younger sibling who filled out a survey on a different blog/vlog but didn't fill out the one here?
Another reason your "trollish" concern about twin studies doesn't get us out of the problem is that adoption studies tend to find the same results as twin studies re the low effect of shared environment.
> Followup research by Less Wrong user “Bucky” determined that the effect fell off with age gaps; the closer in age you are to your sibling, the stronger an effect birth order has.
Some supporting anecdata: I'm the firstborn in a family of six with three triplet younger brothers who are two years younger than myself. Interestingly, the differences between my three fraternal triplet younger brothers are stronger than those between the three of them and myself, and those differences really do line up with the observations made in this essay by multiple metrics.
If I were to identify a cause, it might stem from my parents consistently treating the elder among us as "more mature" and frequently giving us more responsibilities while doing the opposite with the younger, going as far as actively taking away responsibilities. (Yes, they did this even though my three brothers were pulled out of the C-section mere moments apart.) As we grew, we'd reinforce this dynamic among ourselves, often as justification for why the elder deserved certain privileges or why the younger could neglect certain duties. Without a doubt, this sort of treatment had significant effects on all facets of our psychological development, both cognitive and emotional.
I have noticed that the youngest sibling tends to be the "coolest" - i.e. more popular, social, etc. Possibly because they have an older sibling to teach them, hence the stereotype of the cool kid who knows about sex and alcohol because of his older brother. Others have already mentioned differences in parenting, which could contribute to this as well (parents are more lax with rules as # of kids increases -> younger kid spends more time partying and less time studying). Not sure if this is a real effect but perhaps the birth order effects noted here are not so much about older siblings being smarter or more STEM oriented but their younger siblings being less so.
This would be true if we're looking at children of parents in a particular age cohort. But in the general population, the number of people who have exactly one younger sibling is exactly the same as the number of people who have exactly one older sibling (with possibly a very slight bias in favor of the number with exactly one older sibling, because of a slight imbalance in cases where one of the two siblings has died).
This is not compatible with there being an inverse relationship between age gap and birth-order effects. And if we're looking at siblings with large enough age gaps for what you're describing to be possible (remember, the average age of readers here is 33), then you would also have the issue of first-borns being too old to get into this like sub-stack blogs.
Good point about the age gap relationship. My theory would predict a direct relationship, or perhaps inverted-U if we suppose that the older siblings may have aged out.
The inverse relationship really does seem to indicate an in-your-big-brother/sister’s-shadow mechanism at work.
I don't know if you account for half-siblings here and whether this is on the maternal or paternal side.
Maybe scenarios with a biological sibling but not a social sibling are disproportionately of type: dad has a child from a previous relationship but doesn't have custody, has second child in a subsequent relationship.
Dude, isn't the simple and obvious explanation that the older sibling develops a leadership role and therefore has to be more serious and intellectually-inclined? As opposed to comedy or sports?
I'm not sure what the biases in this kind of analysis are, but as a control group I'd be happy to see it done on other blog readerships or other self-selected groups.
Two of my children are quite close in age. They are close enough when they were small it was easy for them to forget that there was a significant age gap. So the older one was convinced for years that he was really smart; and the younger one was convinced for years that he was an idiot -- when actually they're about the same. Also yeah, they get the "oh, reading big science book's is something my older brother does" factor too.
One hypothesis I though of was that. In the ancestral environment, there was a need for different types of skills and personalities, but by the time someone was old enough to see for themselves which personality types the tribe is short of, it is too late for the brain to make the necessary adjustments. One way around this is for children, in early childhood development, to look around and see what personality types and skills surround them, and then pick complementary skills. Since most young children spend most of their time with siblings, this would create the effect. This would explain why sex doesn’t seem to matter, and why age gap does— children spend more time with siblings closer in age.
Source: oldest in a family of four, each of my siblings has a personality strong in the thing that the sibling one above them is weakest in.
Scott could see if this is true by, in the next survey, asking people how much time they spent with their family in early development, versus, say, a day care, and then seeing if more time = stronger effect.
I realize that this doesn’t actually explain why oldest children in particular are reading ACX, this part is more of a stretch, but maybe, since we live in a society which values STEM type mental abilities highly, oldest children optimize for this, and younger children optimize for it less to provide complementary skills.
The problem with this is how do older children *know* to optimize for this. Certainly they don’t consciously, but maybe subconsciously they respond to cues. But how can the subconscious tell?
I hope the next survey has questions about the father relationship. Time spent, type of time spent, his interests, stepdad(s) involvement, general “male role model” stuff. Father-child personality match, likelihood of laughing at a “dad joke” etc.
That doesn't align with my experience (doesn't mean it's not true; n = 1 and all that). I'm a bookworm and an introvert because that's what I am by nature, not because I looked around in early childhood and decided, "I know what this place needs - more bookworms and introverts!!!" Then again, I am an only child, so I never had to differentiate myself from my siblings.
I don’t think its a conscious decision. Scott has a book review that explains epigenetic markers “looking around” in early childhood and developing a life strategy accordingly.
“Del Giudice seems to imply that a similar epigenetic mechanism “looks around” at the world during the first few years of life to try to figure out if you’re living in the sort of unpredictable dangerous environment that needs a fast strategy, or the sort of safe, masterable environment that needs a slow strategy. Depending on your genetic predisposition and the observable features of the environment, this mechanism “makes a decision” to “lock” you into a faster or slower strategy, setting your personality traits more toward one side or the other.”
Or maybe its on a more basic level, where the most rewarding tasks in early childhood are those in which you have a comparative advantage, which is at least partially a function of what society has not invested enough in, so you continue to develop your comparative advantage
The ideas I see are interesting in terms of why older siblings would seem smarter or more interested in STEM... but in general I think it would be useful to ground them back to how exactly they would increase their chance of reading this particular blog. This blog ends up having a STEM stereotype, but actually the content is pretty varied: the biographies of dictators, cost disease, drug discovery and pricing, "Untitled", "You are still crying Wolf", Unsong-adjacent and Fifty Swifties...
Another issue is that maybe older siblings are more interested in filling in surveys? There are older-sibling stereotypes that they have an inflated sense of self-importance; and stereotypes that they have an inflated sense of civic responsibility -- if either were true then that could change it?
I think probably the biggest selection factor on your blog is an attention span? The style of burying the lede deep into the twentieth sub-paragraph (which I'm not knocking -- I enjoy) is the opposite of what pretty much everyone else does -- it is the opposite of clickbait, and means that you normally have to read a few paragraphs in before the hook -- and I have always imagined this is one of the reasons the comment section here is so good. Again, it would make sense to me that older siblings have a longer attention span. If the first child has two parents to entertain them. The second child has two parents and an older sibling to entertain them.
I was wondering about networking effects. I know about this site from word-of-mouth. How do other people generally know about it? Do older siblings have larger networks? What I generally observe in families I know is that older siblings are often closer to the parents' generation than younger siblings, who seem more distant socially somehow -- so in this sense, I guess they have a network boost. I probably get send more links by my parents, aunts and uncles, than a younger sibling of mine would -- maybe I should ask. Again anecdotally, but it seems to me that connections travel up through older siblings more often than down through younger siblings. Maybe it's a seniority thing: it seems cool and interesting to get to know your friends' older siblings -- they're always at the next stage of life; but maybe not so much their younger siblings?
I was reading the comments on an NYT article about nursing homes, and a commenter posted a link to Scott's Slate Star Codex classic "Who By Very Long Decay." I read it and was very impressed (and horrified), and started diving into the Slate Star Codex archives. When Scott shut down SSC and opened ACX, I moved here.
My immediate thought is that second borns grow up in a complex social situation with peers. That may require them to develop more complex social skills/pay more attention to interpersonal situations. That may skew later career choice away from STEM fields. (More specifically some non stem fields gain attraction while stem stays the same, losing relative attraction)
Even Bryan Caplan concedes that the signal that this paper picks up is sound, and weakens Caplan's hypothesis somewhat.
It says that although parental income, environment at home, etc does not affect future earnings as much, one thing that invariably does affect future earnings and achievement is the quality of kindergarten training. I suspect that it is this effect that is even stronger at younger ages (say the first year of the child's life), which is what Scott is picking up in this survey.
First-born children face more pressure from their parents to do something practical and conventional with their lives.
Meanwhile, the key demographic of readers of this blog is "Frustrated philosophers" -- people who wanted to study philosophy at university but wound up doing computers instead.
Within a given family, older-born siblings are older. But within the general population, I don't see any obvious reason this would be true. We're not sampling families; we're sampling individuals.
If you pick an age (say, 33 years), and ask what percentage of first-borns are currently that age, and then ask what percentage of second-borns are currently that age, why would the answers be different?
Or put another way, the younger siblings who are excluded by being too young (or not yet born) should mirror the older siblings who are excluded by being too old (or already dead).
It seems to me that ACX doesn't select for intelligence, it selects for a certain kind of intelligence and temperament. Wide interests (I think of that as fannish), a tendency to want to look at things from the outside, and at least some tolerance for liberal/anti-progressive politics.
Do venues which have smart people but differ on the other factors still tend to have a lot of first-borns?
Yes, the thing that most distinguishes the SSC/DSL/ACX commentariat is not that we are so much smarter than everybody else, but that we're ultra-nerdy rationalists and very disproportionately in STEM fields. See also Nobel prize winning physicists, great mathematicians, and maybe (modulo the STEM part) Harvard philosophers. We like to Think, and mostly about Things. If we have to understand *people*, our first instinct is to turn them into Things that we can rationally think about, e.g. collections of statistics.
I'm pretty sure that, and not IQ, is what is being selected for in the observed birth order effect.
SSC/DSL/ACX readership is almost assuredly selecting for intelligence. It's that intelligence is not sufficient to explain what separates this crowd from other intelligence-selected crowds.
Unless you randomly selected people to answer the survey, could there be a confounding factor that first borns tend to answer surveys and such?
Being the 3d of 3, my opinion wasn't worth much at the dinner table. And I don't rate Amazon products or give Yelp reviews. Could being higher up in birth order make a person more likely to answer ? That would tip the balance in their favor if they tend to self select
i'm the youngest with a 9 year gap to the closest sibling, my siblings were basically like extra parents/ guardians.
I think a good comparison for more research would be to compare with only children. To disentangle if it's to do with 'lots of attention when young' vs 'responsible for someone younger than you' vs 'most competent person around your age in your house' among other things.
I second this. Comparing to only-children could hopefully yield some insights. Although it comes with different confounders: Are families with only one child different from other families? E.g. I know some only-children where the parents were quite old and only barely had a child before becoming infertile (they tried to have another).
Having an older sibling close enough in age helps you develop better theory of mind earlier, which makes you grow up less nerdy, and you are less likely to end up becoming a programmer who reads acx
I didn't read all the comments so this was probably raised before but since you are looking for differences in whether someone reads your blog or not one obvious question to ask is how someone came to read the blog. Specifically I read this blog because it was recommended by my older brother. Perhaps there is some asymmetry in recommendations from older to younger siblings and vice versa. (Although that would mean my case goes against the trend.)
(P.S. I did not answer the survey and I am guessing my older brother didn't either.)
Maybe the first borns are just higher variance so they show up more in more selective extreme groups? And maybe that's because the parents pay consistently more attention to the younger one when both have already been born? Or because of something related to the dynamics of having and older / younger brother, like bullying, competition.. or the younger one having to follow the steps of the older one, inheriting the toys that the older one chose and liked, etc.
I don't think it's regression to the mean where people have a second child only when the first one turned out a decent experience, because I think most people that have a child have more than one, right?
It's not IQ or general smartness that is being selected for. What sets this group (and the Nobel-physicist group, and the great-mathematician group, and maybe the Harvard-philosopher group) apart, as I mention in my reply to Nancy Lebovitz, is that we are that ultra-nerdy rationalists, very often STEM nerds in particular, and we like to Think about Things. Which, really, is kind of weird.
A firstborn child, or a social-firstborn or a younger child with a large age gap, spends the first years of its life trying to comprehend a world full of Weird Interesting Things. Some of those things are called "grown-ups", which are technically "people" but from a toddler's POV they're a completely different order of being. They're weird interesting things.
A (not too much) younger child, spends the first years of its life in close company with at least one other *person*, a person not too different from themselves. And if there's a Weird Interesting Thing that they need to understand, maybe the best way to do that is to learn from that other person.
So maybe the firstborn child is more likely to adopt a Thinking About Things outlook on life, rather than the much more common Understanding People outlook. They're not *smarter*, they just use it differently. And really, even most of the firstborns will wind up in the Understanding People group; that's just how people are wired. But if you're selecting three-sigma outliers in Thinking about Things, you're selecting for firstborns.
This seems to me at least as good a fit to the observed data as any other hypothesis, and better than most.
I wouldn't say so. I've met a few and they generally don't seem to have the requisite level of navel-gazingness. If I had to characterize their personality quirks as a group, I'd say (1) they were very persistent, much more so than the average person, or even the average scientist or smart person. They just never give up, never accept 'oh that's how it is / somebody else must know / man was never meant to know.' (2) They were intellectually ruthless, let nothing stand in the way of their ambition (for understanding or achieving some end). If it works, they use it, and jettison any issues of self-consistency, personal pride, or intellectual pedigree much faster than the average smart person.
It can be a little unnerving talking to a person like that. With a lot of smart people, there's a certain amount of mutual masturabation, to put it crudely. A says something that's intelligent and may be insightful, and B says something back that is intelligent and maybe insightful, and that's kind of the essence and purpose of the conversation -- two people who are exchanging ID cards for the Smart Sophisticated Person's Club. "I see that you are very smart? Yes! Also sophisticated! Allow me to demonstrate with this short essay on complex Topic Z...blah blah. Now it's your turn...!" The 21st century equivalent of a Victorian peppering his conversation with quotes from Cicero (in Latin).
But these people can be exceedingly direct. They don't really give a crap if you're smart or not, they just want to know if you know something that might be useful to them. You could be very smart, or you could be a moron who just happens to possess a fact or experience they need -- and being a schmo with an interesting fact or point of view is of *more* interest to them than being a very smart person in possession of exactly nothing they don't already have.
You know how in school you could sometimes score a better grade than you really deserve by seeming smart and interested, basically appealing to the instructor's vanity? Asking clever questions, making insightful but tangential observations? You can't do that, it doesn't work, and for a lot of smart people (including me) that's a bit disconcerting.
Maybe the 2nd and 3rd born get better at so-called "emotional intelligence" because they have to read the feelings of somebody who is much less rational, the older sibling. The older sibling only has to build an internal model of two adults, and most parents strive to be rational, even-tempered, consistent et cetera with their kid. So the oldest kid finds that modeling people as highly rational even-tempered actors works great. The younger one has to build a model much earlier that encompasses impulse, bad temper, inconsistency, irrationality.
Hadn't thought of that aspect, but it fits. The Weird Interesting Thing that is a grownup, interacting with its own children, is a distinct outlier in the field of human behavior and one should never expect any other person to act that way. Siblings are a better model.
Well, the obvious hypothesis that comes to my mind is parental expectations. One thing that is very obvious about parents is how much they chill out between Child #1 and Child #N, for N > 2. For the first (or, worse, only) child, parents' expectations are sky-high.
My kid is going to be some combination of Einstein, Mother Theresa, and Winston Churchill. Since he needs to get a PhD from Stanford by age 25, he needs to graduate from Harvard at 20, which means he needs to go some super-competitive magnet high-school after skipping a grade or two in a superb private elementary school....so damn it we better get cracking at getting him into that enrichment pre-school that has only people with PhDs changing diapers -- he's already 3 years old for god's sake! And stop giving him the regular mashed peas, he needs the choline-vitamin E-probiotic fortified 100% organic mashed peas harvested from the slopes of Vesuvius by the lineal descendants of Aristotle. You want him to turn out ordinary??
Comes child #2 or #3 and it's like hey honey little Billy was eating laundry soap again and he looks unhappy, could you maybe get him some water to wash the taste out?
I remember Gilovich talking about birth order effects in his Behavioral psychology class. He seemed pretty convinced. He liked the explanation that birth order effects stem from having to teach the younger sibling things and that you can see the same effect with only children in the US whose parent's first language is not English. They had to teach their parents.
Could the answer be hiding in plain sight? If you were to start club called the "Older Than 10 Club", wouldn't you expect the membership to be skewed towards older siblings? Either:
a) if both siblings belong to the club, they don't bias the sample
b) if neither sibling belongs to the club, then they don't appear in the data
c) if only one sibling belongs to the club, the older one is more likely to be a member, on account of the fact that there are more people older than 10 than there are people younger than 10.
Maybe this blog is most attractive to people who are older than a certain age, on average, and that accounts for the bias?
"The current scientific consensus is that parental investment in the early years of life doesn’t really increase IQ or educational attainment .. This research challenges those assumptions. If it’s right, the difference in parental attention between an only child and a child with siblings seems to have noticeable effects later in life."
The implication here is that birth order -> IQ -> SSC reading. As a first-born SSC reader I like that theory, but I can think of some more plausible relationships.
Maybe first born have had less socialization and are more likely to enjoy solitary interests?
I can propose one more hypothesis. Firstborn are not more intelligent, they try harder. They grown up being more intelligent than their siblings, their "intelligence" is a part of their self-image. Yeah, now I'm talking about myself. And I'm a pretty severe case of it, up to panic attacks when I didn't manage to hold an image of a very smart person. People really asked me "what happened? why you gone all white?". Yeah, I'm talking now about me, not about all firstborns, but I'm pretty sure that one of two big reasons of my condition is me being firstborn. I was responsible for me and my brother all the time. If my brother fall into a river, than I was asked "how it happened, and why I didn't prevented it". It was like my brother fall victim to my stupidity. It was not literally said, but "you need to be smarter" was one of phrases I heard a lot of time being a kid and in my teens. I rebelled at 14-15 against this responsibility. It is a different story, but note that I rebelled against responsibility, not against me being smarter. It took me 20 more years to start fighting my self-image of an intelligent person.
So, my hypothesis is: firstborns try harder to seem intelligent, they develop the whole strategies how to be (or to seem) more intelligent than others. These strategies include "tactic" reactions to stimuli, allowing to hide their "stupidity" (like if I did not understand what happens, I give others a possibility to ask "what happens" or to say/do something that might help me to understand what happens, and I would try hard to be unnoticed). But it doesn't stop here, firstborns learn to be curious. In an academic sense of the world. To learn what other think about some problem is nice, when you forced to talk about this problem, you could make a reference to a few sources, lay out a few different opinions and then maybe even to verbalize your own thoughts on the topic. Or in other company it is better to "plagiarize": to express some opinions without references.
I told, that I'm a severe case, and I really do not know how bad it goes in minds of other firstborns. But what I'm trying to say, that it is not just "I try harder", it is how I live, it is who am I. I read ACE not because I need more smart thoughts cached, I read because it is fun. But it is fun, because I learned as a kid, that intelligence is my inherent psychological trait, and as a teenager I found ways to match to this trait. It is just conditioning.
I cannot say, I know, how to prove it. I'd try to get an operational definition for my condition, to get a way to measure it by looking at behavior. Then to use it on many people, and to study those who hit high scores on the condition -- let them fill a lot of questionnaires, find all the correlations. Then probably we could find an easy to measure trait which is highly correlated with the condition. And then we might find it in the data gathered here.
Though, there was mentioned psychological research of siblings? Did they tried to give some unsolvable task to siblings, while measuring time they spent on it before giving up? Or to place them in unexpected difficult situations, while measuring "smartness" of their way to deal with it. (I called it "smartness", but really it is not about smartness per se, it is about how they manage to look intelligent people.) It may be tricky to operationalize, but I believe it is possible.
1) if I understand Becky's comment correctly, the dataset contains more people with zero biological and some social siblings than the other way around, which is surprising to me and may indicate an important selection effect.
2) the whole essay seems to use "being a reader of ACX" as equivalent to "being more intelligent than the average in general", which doesn't sound justified by mere correlation. The fact that ACX readers are more likely to be highly-educated and also firstborns doesn't automatically mean that firstborns are smarter in general.
Most obvious answer I can think of is seniority dynamics. Confidence and success breeds further confidence and success, and the oldest sibling is always at the top of the hierarchy. This fits with the huge drop off we see between Sibling 1 and Sibling 2, and the much smaller effect when going from Sibling 2 onward.
I don't think parents have much to do with it. Kids get most of their social input from peers, not adults, and siblings - especially those close in age - are the most important peers of all.
"One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower?"
Yes, the first year is important, but also consider school/preschool: Age gaps over a certain number of years basically give the second child an experience more like that of a first child, since the first child is out of the house or at least more independent.
I thought it was interesting that the decline of the ottoman empire began within a generation after they switched from primogeniture to agnatic seniority.
As a first born with good general success compared to my siblings, the largest difference today is our openness to experience, and willingness to try to fix a problem. They are just as smart as me usually.
I suspect the openness part could be partially due to me not having much help solving problems when I was little, I had to do it myself, or it wouldn't happen (my parents weren't great at helping) whereas my siblings could always get assistance from an older person rather than do it themselves. Having good initiative on learning and doing pays compounding returns.
I'm doubtful parenting has anything to do with this, likewise infancy, as the effect gradually reduces over 10 years. To me the most plausible explanation is firstborns' requirement to figure out a lot of things on their own. This would inculcate increased amounts of "seeking for the truth"; trying to figure out how the world works. The closer in age a sibling is the easier it is for them to learn by example of the older sibling or to just be directly taught by the elder. A 15 year old would struggle to teach a 9 year old relevant things that the parents couldn't teach just as well.
Supports: This is a social explanation, not biologically dependent. It explains the smooth reversion to the mean rather than dropping off suddenly at some point (as an infancy based explanation might suppose).
Problems: I would expect a small amount of gender disjunction but that seems not to appear in the analysis.
Tests: The effect should decline in more communally raised children, where they have very close relationships with children their age (or one year older).
Disclaimer: I am an eldest with 3 younger siblings (none of who read SSC/ACX).
Great comment! I was thinking of the older teaching the younger too. But instead emphasized the benefit the older child might enjoy by teaching things they learned to the younger sibling. I feel like I get a better understanding of an idea once I’ve taught it to someone else.
Thanks. That's an interesting thought and could be contributing, although in my personal experience it didn't feel like that was significant. I definitely understand things better when I explain them but I seldom tried to teach things via explanation to my siblings.
Here's what I think of the first born. Enneagram 8.
Challenger
Basic Fear: Being controlled or violated by others.
Basic Desire: To determine their own course in life. To protect themselves.
Eights want to stand alone, to have power over their lives, and to achieve their goals. They are extremely driven, resourceful, and propelled towards their vision and purpose. They don’t want to feel indebted to anyone, emotionally vulnerable, or in any way dependent. Autonomy and freedom are vital to their happiness; the only problem is that they may defy being vulnerable so much that they miss out on fulfilling relationships in the process. These types crave a sense of intensity in their lives. Whether they’re race-car driving or starting their own business, they enjoy proving naysayers wrong and testing their abilities and strengths.
In childhood, Eights felt that they had to grow up quickly. Early on they felt that they were in some way responsible for the welfare of their family. There was no time or safe space for vulnerability – they had to be strong. Survival issues were at the forefront of their mind. Being gentle, giving, emotionally open – these typical INFJ characteristics were probably repressed because it didn’t feel safe. In some way they felt there was a risk of rejection, betrayal, or pain if they let their guard down. They developed a tough, independent, hardened demeanor as a way of dealing with their pain.
Eights are in the Gut/Instinct triad of the Enneagram. This means that they have underlying issues with anger. While Nines avoid their anger and Ones repress it, Eights express their anger. They like straight-talk and directness and tend to be assertive themselves. When threatened or controlled they can become explosive and intimidating. They feel very defiant of any institution that tries to control them – and they may make life choices simply to rebel against that institution. Whether it’s dropping out of school because the teachers were too controlling, marrying someone a parent doesn’t like, or driving faster than the speed limit on a bad day.
Sincerely believe that its the forced leadership. In group play, (and many other situations) the older sibling has to take to the lead. This means generating play ideas, structuring play, and reinforcing play rules. This would explain why the effect is stronger when the gap is closer, and how it could be social without necessarily being based on parental involvement. I think that this could bias some personalities towards valuing things like intelligence and independent thought without actually being smarter (valuing intelligence might make you more likely to invest in your own, but wouldn't necessarily bump you out of your bracket). You might see some boosts in creativity from early practice - but the overall thing that gets affected is not the underlying skill but the perception of which skills are desirable. That would mean that your strongest sibling-order-effects would be in preferences - characters you relate too, ideas that draw you in, or blogs you read.
Father of two kids here, so my sample size is 1. However, I suspect that the cause is "bossiness". In my family, the younger sibling is the bookworm; she loves to read, and is by far the more STEM inclined. But the elder sibling absolutely loves to "mother" her, and always wants to be in charge of whatever games they play, even though the age difference is only 1.5 years. As parents, we have to constantly work to make sure that the younger sibling has a say in things. I would hypothesize that 10+ years of unintentional "leadership training", or conversely, "follower training", might make a significant difference.
Maybe older siblings are poorly socialized due to having no older siblings, thus more likely to be "on the autistic spectrum", thus more likely to subscribe to AC10.
If my first kid is smart I am more likely to have another one. Add some random distribution of intelligence between kids and regression to the mean and we have an explanation.
Another possible mechanism, which is biological, but not genetic, is the potential effect of early illness. Just anecdotally, my first child wasn't sick for the first year of their life due to lack of exposure to other kids, but I fully expect my second to be sick much earlier due to picking up things from the older one. I'd expect this to attenuate over time as the first is more able fight off infections before they spread to others.
If this is true, I'd expect this effect to vary based on when/whether childcare like daycare is used (and what type). Also does this vary over time? Were there birth order effects in the early 1900s, for example? How do they vary across countries?
One (anecdotal, unscientific) observation I have made is that boys with older brothers (this one is sex specific) tend to have more tenacity than those without. I attibute this to the type of rough play the boys tend to get into (much to their mothers' chargrim) wrestling, stick fighting, etc. The younger brother will almost always lose such games and yet is expected to play on anyway to grow stronger and hope for the sweet moments when he can catch the older brother off guard.
I would love it if someone could suggest a way to test this theory or even better actually test it.(The hard part I believe it's coming up with a suitable metric for "tenacity", I am highly skeptical of anything involving self reports)
Notice how society has gone from "it doesn't matter if somebody is gay" to "it's good if some people are gay".
Why? Even in a completely tolerant world, homosexuality is going to lead to at least modestly inferior life outcomes (smaller dating pool, harder to enjoy the rewards of parenthood, etc). If a person is by nature going to suffer those hardships, certainly we shouldn't add to it with bigotry and probably we should try to help them in at least some ways, but why is it *good*?
There are people who believe that it is *good* that some people are congenitally deaf. And, as we've seen here a couple of times, people who think that it is *good* that some people suffer various mental illnesses. Do you share that view, in the name of tolerance or diversity or whatever?
"Baseline" is a complicated term, see the section on choline at https://astralcodexten.substack.com/p/obscure-pregnancy-interventions-much for what I consider pretty good evidence that choline supplementation during pregnancy affects child IQ.
there's a lot of choline in breastmilk so that could potentially cover some of that 6 years
A young, unmarried mother might have different genes to pass to the child. The more experience a child has at running the family, when the parents are younger and less experienced with more energy to try to be good parents.
But the firstborn effect is weaker when the age gap is large. I'd expect the opposite if it were maternal age.
"You may be able to think of others besides these."
Maybe older siblings compete with younger siblings in various ways, and, *being older*, naturally win. e.g. maybe older siblings are much more successful at bullying younger siblings than vice-versa.
Yeah always winning maybe builds your confidence and help make you more persistent in education etc. maybe
But they don't always win. They're better at structured reward activities but more maladjusted to social situations seeped in ambiguity - essentially, dealing with peers of various proclivities vs manipulating/pleasung their parents
How about the first child's experience and ability at bossing the parents around?
That doesn't square well with the "path finder" theory. Older siblings have to fight all the fights with the parents, whereas the younger siblings generally profit from the results without having to put in as much of a fight on their own.
Perhaps asserting yourself in those arguments provides good practice for later life in some way?
I was specifically critical of the "bossing the parents around" statement. Due to the "path finder" aspect of the oldest sibling, I'd argue that younger siblings get to boss around the parents much more often than older siblings.
I agree with your idea though that having to assert yourself on those arguments might provide good practice for later life.
I could have been more clear in my first post though.
Isn't being good at structured reward and bad at ambiguous social situations the nominal path to get into STEM (and thereon to get into ACX) ?
Seems like it. Anecdotally (I don't even remember if I participated in the survey) this lines up perfectly with how I would describe myself and my sibling.
The oldest is saddled with responsibility and success from the start. No time for play unless it's to win.
This jives with my experience as the youngest sib from 3 boys. Although as a counter, my current age is 29, older sibs are 34 and 35 and I'm the only ACX reader of them :-S
For sure! Having watched a 3 and a 5 year old interact for 3 years, it seems like being a younger sibling means spending a LOT more time being bossed around by someone 2 years older than you. Like, multiple hours per day minimum 😬
Oddly, with my kids it is the opposite. The oldest girl got pushed around by the middle girl, now the youngest pushes around the middle. They are all girls so there isn't boy levels of pushing around, but generally when there is "not playing nicely" behavior it is the younger pulling dominance.
Are children with experience being a bully, or experience effortlessly prevailing in competitions, more likely to go into a STEM career? That would be counterintuitive.
One (trollish) explanation: people who read ACX are Weird. Most people are bullied/pressured out of being Weird by peers or older siblings, with siblings having a stronger influence. Most 1st borns are Normal, and quash ~all incipient Weirdness in younger siblings. But even if the 1st born is Weird, there's still pressure from peers for the younger siblings to be Normal.
Funny, I was just making the argument to someone else that as an only child, I was basically a firstborn whose weirdness could rage unchecked indefinitely.
I'd guess it's more about younger siblings being more influenced by their older sibling than by their parents. which would probably lead to some advantages and some disadvantages.
Oh, interesting. My own default assumption is actually the opposite of Scott’s (1): being older doesn’t matter for the time during which you have your parents’ undivided attention, but rather for the time afterwards when you have significantly *less* attention because your parents are dealing with a newborn, leading you to develop independence and self-direction much younger.
It would be really interesting to look at families where the oldest child had a significant condition or disability that required lots of parental time and attention, to see what effect that had on the younger sibling(s).
Social first-borns are a third parent to their younger siblings. First-borns are replaced as the cutest thing in the household. This is the effect; not more parental attention. They become parent-like and get attention for being helpful instead of cute.
Yes, one of the flaws in the notion of "shared environment effects small -> parenting doesn't matter" is that parents just straight up teach their children differently, not just differentiate in quantity of attention.
Yes, exactly. This is what I wrote above. The older child becomes the leader, hence looks out on the horizon. The younger follows and competes with the older, whilst the older is following the parents.
Yes, exactly. I see I am at least the third to suggest this effect; I should have read further down so as not to duplicate. Insightful folks, ACX readers :-)
As as oldest child, my experience was something like I didn’t fully register the “child” category before my sister was born. When she came along it became clear that we were not 3 equals (my illusion before). It was not a demotion into less attention so much as it was a demotion into a different category of being. They had allowed me to believe I was one of them; when the sibling came along that was suddenly obviously not true. Never to return again, except in echoes if the sibling were sleeping over at a friend’s, out of the house.
Also if Harris’ “nurture assumption” book is correct and peers play a larger role in development than parents do, the older sibling would be an in-home influential peer for the younger in a way that wouldn’t be reciprocal (usually) unless the younger sibling were dramatically more competent in some way.
As a first born, did you ever find yourself being the boss of the family, not just younger children?
I think I intervened between my sister and my parents, in terms of trying to interpret their behavior for her. I was never intentionally the “boss” figure partly because one parent worked almost all the time (dad) and so the center of gravity of the household was not usually present, so not easily challenged.
I’ve definitely known people who had to babysit/quasi-raise their younger siblings and that was not my situation.
This is the opposite of my experience. My closest sibling is six years younger than me, and yet I distinctly recall, even prior to their birth, that I didn't at all think of my parents as equals, or even the same as me. I remember being astonished when I learned that they were once children.
That was definitely my experience, and that of my kids.
We are assuming the parents are the bosses but I often see the first child being the boss of the parents. Then it's easy to be the boss of any younger children.
This doesn't quite square with the observation that birth-order effects are strongest when age gaps are smallest though.
I'm understanding that birth order effects are strong for a few years, before dropping off around seven years. Some effects seem stronger after a few years, rather than the minimum difference.
Even with that, a full year of difference (pretty much the minimum biologically), can be pretty dramatic. The difference between two and one is huge, and that's when a lot of these effects are being built into the siblings. Sure, by the time we're talking 19 and 20, that's a tiny difference, but by then the relationships are pretty solidly complete.
The closer they are the most they'll interact.
This was my first thought, and it makes sense why the effect would get stronger as children get closer in age. We have almost irish twins and for better or worse, have always leaned on the oldest one to help with the younger one (and then the younger two), possibly in age inappropriate ways. Had there been a bigger age gap, we wouldn't have needed to rely on the older as much.
And I think this goes against his natural proclivities. He's very much innately not a "first born" child, or at least his first born traits developed much later, compared to our friends first children, which implies to me it's learned behavior.
The middle I think was innately a first born (basically driven and didn't care what other people thought) and he has been molded into a more typical middle child, turning into a pleaser, which I feel is probably not ideal, but it is what it is at this point.
It's cool to see that the effect persists in the new data. It seems that we older siblings need to convince our younger siblings to read this blog!
I'm wondering, does the effect remain when you control for age? First siblings will be older on average.
I think this blog's viewership is mostly 30-somethings? regardless of which age bucket it is, any given adult age bracket should be evenly older or younger siblings, I believe
I remember that Scott said on average, older siblings were only 1 year older than younger siblings (out of the entire pool, obviously, not within the same household) so that is probably not the explanation.
I had this thought too, back when we were looking at the first round of results. I think the fact that the effect is stronger for siblings closer in age, and weaker for siblings farther apart in age, contradicts this hypothesis. If it were just that older people had done more stuff and therefore had had more time to stumble across interesting blogs, then we would expect the effect to get stronger the larger the age gap grows. (Though age might explain the Nobel laureates or whatever.)
If you are sampling individuals, rather than families, why should first siblings be older on average?
Like, if this blog attracts readers between the ages of (simplified example) 20 and 40, then there will be some 20-year-old first-borns whose younger siblings are too young to be eligible, and also some 40-year-old second-borns whose older siblings are too old to be eligible, and presumably these cancel out?
The number of only children in the US doubled between 1971 (11%) and 2015 (22%), so there must be correspondingly fewer siblings.
Makes one wonder if primogeniture wasn’t arbitrary.
Well, it also wasn't arbitrary in the sense that keeping the family's assets intact rather than dividing them is important, and in the sense that having a very clear line of succession minimises infighting, and ultimogeniture would be too likely to put a baby on the throne.
But I see your point that maybe first-borns are meaningfully distinct in other relevant ways too
That's a good call. The older child always seems the more responsible child.
This is why I want to ask if the thing SSC is selecting for isn’t conscientiousness first and foremost, with programming being full of conscientious people precisely because there really are right and wrong answers
When I think of a field that demands concientious people, I think Civil Engineering, not programming. When you can compile and test your program in seconds it removes much of the need to get it right the first time.
Programming requires a lot of high level thinking, holding different threads in your head simultaneously.
Yes, but that's intelligence not concienciousness. I'm a software developer and bottom 1% concientiousness. It seems like a good career fit to me.
> When you can compile and test your program in seconds it removes much of the need to get it right the first time.
Most programmers can't do that. You can test a few things, but when you're working with dozens of other developpers on a platform that has thousands of users, either you're concientious, or you're going to increase the support workload a lot.
You can't build your software and run tests whenever you want? I mean, sure, you're not doing integration tests all the time. But most 'careless' errors are caught in syntax and unit tests anyhow.
My experience is largely in small team application development, so I can't speak to life in Big Tech. But it seems to me that most software is obviously more tolerant of carelessness than, say, bridge design. You can catch your errors far more cheaply.
It seems like you're assuming careless development but conscientious testing, and then labeling it as un-conscientious overall. It strikes me as the opposite, a conscientious person can still rely on tests to catch their mistakes as part of their process.
Writing good unit tests sounds conscientious to me, and writing code with syntax (or other basic) errors (that you know you will catch with the tests) isn't necessarily a lack of conscientiousness. (edited for typo)
I can build the software and run the unit tests, but the integration tests are ran every day, and need a few dozens of VM. Syntax errors and unit tests don't catch the big issues, which are logic issues when many services are interacting.
> But it seems to me that most software is obviously more tolerant of carelessness than, say, bridge design. You can catch your errors far more cheaply.
It's not like software is built as tolerant as bridges, since its more tolerant. Business won't let you spend as much time on "safety" as if you were a civil engineering firm, because that would be time mostly wasted. Also, there's a great series comparing regular and software engineering from the pespective of people that have done both, concluding that our work are more similar than different https://www.hillelwayne.com/post/are-we-really-engineers/.
I see that sentiment that "we aren't civil engineers" all the time, and I don't understand it. Especially since most of the time it comes from people with absolutely no experience in civil engineering. Software is not a bridge. But the same techniques can be applied. It's all engineering in the end.
I'd say less that catching programming errors is cheaper, and more that FAILURE to catch them is cheaper. A software bug that makes it all the way into production tends to cause less harm than a design flaw in a bridge or an elevator. Especially if the software in question is, say, a video game.
If you had to produce complex software with literally zero bugs, I expect that would be _ruinously_ expensive.
We don't hold software to anything like the same standard as bridges. (This is not just a social difference, but actually a legal one--software is allowed to disclaim liability in ways that other products legally can't.)
This is a good poll question
I feel like it shouldn't need to be said that Scott's poll of ACX readers does not generalize to medieval Europe.
I mean, what really is the relevant difference between running a manor and reading essays on nootropics?
And yet!
The English in the early 20th Century were quite smug about how their system of primogeniture created a strong, calm, self-confident ruling class prepared by their upbringing to rule. Even the House of Commons tended to be full of near-aristocrats: e.g., Mr. Winston Churchill had the good fortune to be in the now-dominant House of Commons because he was the oldest son of Lord Randolph Churchill who was the second oldest son of the Duke of Marlborough.
Some other nurture explanations I’ve heard:
- Firstborn siblings spend more of their early years exposed to and learning language from adults versus other children who are only slightly older.
- Similarly, firstborn siblings are more directly exposed to praise and expectations from their parents and other adults, vs the praise and social validation of another slightly older child. Thus they become more oriented to achievements that will impress adults, such as performance in school.
My first born, it was all organic food, Montessori, and no screen time.
Her youngest sibling was born holding an iPad eating a Happy Meal.
And do you feel this had any long-term effects?
Solidarity, brother
This matches my experience.
On the other hand, I'm screwing up certain things less the second time around, so surely that counteracts the effect of my greater laziness?
Linguistic research on children has found that the critical period of language learning goes until age 10-12, so any child would have had a lot of exposure to lots of other children and adults in the relevant time period. It’s possible that there is a slight effect on margin, but it seems a bit doubtful.
+1. As the firstborn of 4 and the father of 3, the most obvious distinction to me is that the firstborns are socialized by adults while the younger kids are socialized by siblings. This aspect is consistent with the declining effect when age gaps are large - much older siblings aren't around to socialize younger ones.
Are you sure that older siblings aren’t just more likely to try and please authority figures by performing thankless tasks like filling out user surveys ?
The comment section needs "Likes" for comments like this one. Perfection
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Funny, but also very serious objection to the premise. The selection may well be taking place at the survey stage, not at the readership stage.
In theory I should be able to figure this out - I included a question "How close did you come to not filling out this survey" to see if this could be used to analyze response bias. I don't feel like actually looking at it right now though.
I've read about first-born superiority, so if I were a first-born, I might want to participate to find out more about my superiority. But, in a Harvard class the professor asked the students to raise their hand if they were first born. Most of the room raised their hands. It was a philosophy class. As a second child, I see the oldest one wanting control with their parents in supportive roles. They have good verbal skills and know what to say to get what they want.
Edit: This is wrong! See André Röhm's comment and my response.
<wrong>
Most people are first-born children, if average family size is not too high. Suppose for illustration that 30% of all non-childless families have one child, 40% have two children, and 30% have three children. Then by simple arithmetic, 30%+20%+10%=60% of these children are first-born. And Harvard students come predominantly from well-off families with relatively low birth rates (see https://www.statista.com/statistics/241530/birth-rate-by-family-income-in-the-us/).
</wrong>
I stumbled over it for a bit, but I am pretty confident you made a slight error here.
The real answer in your example is "50% of children are first-borns".
(Do the math for example for 10 families, and calculate the number of total children)
What you calculated was equivalent to answering "If I pick a random family and then pick one of their children at random, what is the chance to select a first-born?". This underestimates the effects of large families.
Even then, I believe your point still stands that first-born's can be more likely than expected. However, if this blog has such a strong selection effect, would we expect Harvard to have none?
You are absolutely right! Doing it properly, the proportion of first-born children is equal to the the reciprocal of the average number of children in non-childless families. In my example, that would be 1/2, but I don't know what the average is over real-life families, or families with a child at Harvard.
This would be a nightmare to try to control for, but I love it (disclaimer: third child, issues with authority, may be biased)
This is where it might be helpful to have survey data from other blogs that are very different in character from this one.
Maybe being older you get lots of opportunities to explain/teach things to a younger sibling, this makes you more reflective and self aware hence more likely to go into higher education get a PhD etc. The decline starting at 8 years might be because at 18 you move out and stop teaching your younger sibling things while they are still quite young and can be taught a lot of things, i.e, less than 13.
Yep, makes them nerds perpetually jealous of their cooler younger siblings, who learned social skills from slightly older other kids rather than adults
Joke's on my siblings. I stole their toys and made them solve math puzzles to get them back. No social skills were learned in the process.
LOL, that's hilarious and wonderful
Absolutely, plus the corollary which is that younger siblings often don't have to learn things for themselves through experience or the hard work of reflection and self-awareness, so they end up getting less practice in those areas. Also, older siblings will often just do hard things for their younger siblings out of impatience, rather than let them figure it out themselves.
There is teaching, but as a second born, I see the first born wanting to control and get the money first, for college. The first born's verbal skills may get their parents to expect more from them and pay more for them. Though they might be the leader, good leaders hire
talented people. A good leader just knows how to control people, time and has a goal. Brains they can hire. They respect time as they usually pay an hourly wage.
As a younger sibling with a B.S. and an older sibling with a doctorate, I came here to post that exact hypothesis.
Anecdotally, siblings relatively close in age are often playmates, and children whose parents are academically inclined definitely engage in play with the older teaching (bragging about?) what they just learned in school. For me about 2/3 of what I encountered through grade 6 I already had pre-exposure to via this method.
It's funny how school changes to impress parents. I brought home new math and my parents had no idea what it was. Then when I was an adult I saw little kids bring home new math and I was dumbfounded even though I had been a math major for a while in college. The kids always impress their parents with the new things they are learning. Parents then think their kids are so smart and decide that kids should go to college. How do they do it? My sister learned the Dewey Decimal System for finding a library book and her kids learned to use a google search.
There's also far more a 5 year old can teach a 3 year old than an 9 year old can teach a newborn
My personal hypothesis is that the greater uncertainty involved in raising a child for the first time leads to higher openness to new experiences. I'd guess this can go down a number of different paths in practice, but that cultures situated outside of the mainstream will be disproportionately firstborn as a result.
I've heard plenty of tales of parents being overprotective with their firstborn and then realising that kids aren't actually that fragile and letting the younger ones be more freeform, so I'm not sure the cause you're positing exists in the first place
Exactly, my experience and the one I see as well. New parents insist on strict regimes for everything, everyone over-thought and amusing to more experienced parents.
Get down the line and "good enough" is, indeed, good enough
Sure, but that "openness to new experiences" with me (first born) translated into:
-Being one on one homeschooled and raised on the edge of some interesting socially non-conforming groups.
For my little sister, that "good enough" translated to:
-Just go to public school and get fed the standard mainstream culture.
Indeed, classic high variance strategy vs conformity
Best advice I got when I became a parent was from a mom of 3 boys. She said to ask myself “Would I be doing this if it were my third kid?” Saved me a lot of effort so far.
I speak from experience as a firstborn. I have distinct memories from high school of feeling resentful that it felt like I was the guinea pig. I certainly can't speak for all firstborns, though, and don't really know if my experience was common.
I have shades of that as well. I couldn’t believe what my younger sister got away with.
bwahahahahaha, my brother still grouses about it "jokingly"
But the first born learned to use verbal skills to get what he wanted even when parents had made tough rules. More obstacles presents more practice time.
No doubt.
I wonder if that has changed as parenting standards have increased with this generation.
My older brother experienced much of what you did. Unfortunately, most of the experimentation was the cw/assumptions my father made based upon what worked for his own upbringing - go to Catholic school, play football, etc.
My brother did, and even at times felt compelled to profess he liked some aspects of it. But he was miserable. A complete first-born nerd, he would go on to make good friends in college, become a brilliant surgeon, and win an award from his med school, one of the best in the country, for his healthcare policy work.
He was the most miserable adolescent you ever met. His bad experiences at the hands of his peefs haunted him literally for decades.
My parents observed and, once my brother was able to begin to process it all and speak up, accepted his assessment. As a result he moved to an excellent, small, academically oriented school (without a football team) for high school.
I got the benefit of that environment from the third grade, and more importantly of their open-mindedness when I also was not what one would term a typical small-town Louisiana kid.
As a result I was just a more relaxed and amiable kid, comfortable in my skin. Part of it was younger child peer interactions (vs older child pleasing parents). But a big part was I trusted my parents to listen to me and do what was best for me in a way my brother did not experience, and was accepted by my classmates at the smaller, more academic school from a young age.
God bless man. It all works out, but it doesn't mean it's not tough at times
Totally. The first kid into teenage years is the one who triggers all the unresolved teenage trauma in the parents. I had to muddle through it with little guidance. When my sister came along a) they were worn out from fighting me and b) there was a path and c) they realized some of their strategies didn’t work & updated to better ones.
That first born having to fight for what he wants, verbally makes him skilled at this. I have heard about first borns resenting parents, anger fuels their desire to show their parents a thing or two. They see their parents are new at this. Take advantage when possible. I've known first borns who waited to get divorced until after the parent died, so he could show his parents he was a success and right.
How do you know that "birth order" is not just a proxy for "age"? Maybe people who spent more formative years prior to smart phones are more receptive to long essays of the sort that you write.
Could simply filter for respondents over ~20; There's no reason a 40-year-old reader can't have older siblings, so the effect of younger siblings being too young to be readers would only show up in the youngest readers of the blog.
I remember that Scott said on average, older siblings were only 1 year older than younger siblings (out of the entire pool, obviously, not within the same household) so that is probably not the explanation.
Some thoughts:
- Nice work.
- First borns are part of the "parental teaching structure" of subsequent kids.
- and also competitors, cooperators and imitators. I have a 9 yo and 6 yo and I can tell you they are both forever different, on questions of basic personality/desires because they have a sibling. There are things they do/love/hate because of how their sibling feels about them.
- is there any value to looking at school situations (such as Montessori) that often mix age groups? A class room of all 2nd graders is going to have different "social sibling" effects than one that's 1st, 2nd, 3rd all together.
- and what about the past, when almost all kids were raised more or less in a group - a swarm of cousins of varying ages? Being the first born in a house that only ever has 2 kids is one thing. Being the first born in a generation of cousins probably has different implications.
- did you ask any questions about pets (insert snark about "substitute kids") in the household?
You say snark, but my partner and I often joke, only semi tongue in cheek, that our baby is almost getting a second child experience because the dog still needs attention/walks/etc.
I mean, you're definitely right! At this point with joint dog-human society, you might be able to detect sibling effects on the dog too from having an older/younger "sibling" human. Not sure how to do the conversion to dog years though. ;)
I wonder if Kevin Leman reads this blog.
You're only looking at 1/3 to 1/2 the picture. The interaction between the siblings, especially the role assumptions that go on.
Our children are 18 months apart. Just before our second was born, my wife took our daughter to the toy store so she could have a baby doll of her own, something that looked a lot like a real baby. Mom had the daughter give her baby doll a name (Baby Mike) ... OK ... with the thinking mom would have here baby, and our 18 month old daughter would have her own baby to mimic mom, instead of wanting to hold her baby sister.
Great idea, but wrong. Baby Mike went into the toy box to almost never return. Yes, she wanted to hold her baby sister, and we allowed this with close supervision, the older daughter was only 18 months after all.
But what happened was a total bonding, the younger grew up faster, as the protégé of the older, and the older did revert some especially when it came to diaper training. We had read about, and expected this.
I think there was growth and leadership developed in the older child, far vision thinking if you will ... which is pretty much what this forum is about.
The younger child didn't/ doesn't look to the horizon as much as she follows her older sister still in a lot of ways, they're 29 & 31 now.
And yes, I'm the elder of two, my sister is 16 months younger than I.
Your eldest is the first grandchild. Kids can compete to have the first grandchild for favoritism {my observation}. So your oldest has a large audience. Don't want to disappoint.
Whenever this topic comes up, I wonder how only children (no siblings) stack up against firstborns. What percentage of this blog’s readers are only children?
I’m also curious about how many female readers of this blog are only children vs male readers.
Anecdote time: I'm an only child and a female reader of this blog.
Female reader here, one younger sibling (sister), five-year age difference.
But I was born when my dad was a physics PhD student, so this blog or something like it was pretty much looming ahead of me from the get-go.
The response is usually 90:10 male: female split.
I knew that about ACX, but I’m curious how many of the readers are only children, and whether the 10% female readership includes an outsize number of only kids.
In 1976, 11% of American women over 40 had borne only one child, but by 2015 22% were “one-and-done”. I have a strong feeling that only children are more or less firstborns, so likely to be over represented here. I’m wondering if that might be especially true for the women, since anecdotally it seems like we’re outliers in various subtle ways.
Maybe “reading ACX” is more of a proxy for “feels benevolently toward or perceives deriving benefit from interactions with analytical males.” Seeing the application of “that brain” to issues in the world at large is one of the draws of ACX for me. Some people (even with STEM careers etc) prefer to only deal with applications of “that brain” occasionally, or only at work & never outside, etc. They might have or use “that brain” themselves but need/want different social input.
So the father-child relationship might influence this. Most of the research seems to look at mother-child dynamics.
LOL I resemble that remark. I like hanging out with analytical males so much, I married one.
I'm currently mostly a homemaker, so this community has been a really valuable outlet for intellectual discussion. I enjoy using "that brain", and indeed most of my close friends have either been men, or women in STEM careers. I've often been the odd woman/humanities major in the room.
My parents didn't have much of a science background, but my dad was a very "no BS" kind of person, and my mother was quite intensely emotional, which I think is why I always found comfort and refuge in an objective, rational approach to the world. And being an only child, I kind of got away with being as weird as I wanted for a longer time than someone with (especially younger) siblings might have.
I saw those graphs and immediately thought of Benford’s Law.
In my experience youngest siblings can instantly identify each other. They have been strongly socially conditioned; they were always the cutest, they were always smaller than their siblings, and parents had relaxed relative to the first kid. They're used to losing arguments and having things not go their way (being younger and smaller, not necessarily more or less on track), unless they work disproportionately hard for it.
Some anecdotes:
1. My parents *returned* the gameboy I was given as a birthday present, but my youngest sibling was allowed to have multiple consoles.
2. Although I'm three years older than my sister and she's three years older than our youngest sibling, we all learned to read within two years; I was late, she was on time, and the youngest felt left out and taught themself to read at the age of two. (Those early digital books that highlighted and spoke the word at the same work wonders!) Now, of the three of us, 1 and 3 are the most avid readers. (But 2 got a neuroscience degree, she didn't get off easy!)
3. My dad taught us all to program at the same time; we all started with the same level of competence and quickly developed our own styles. Of us, 1 and 3 are employed as software engineers now; 2 lost interest. (This was also part of a larger experiment on us; in the early 2000s there was a theory that girls didn't enter programming because they didn't have a cohort, which my dad found to be a testable hypothesis, so he not only taught us but also most of my sister's school class. It did briefly keep their interest as a communal activity, but it's not clear it had any long term effect.)
I (a first-born) have also surrounded myself with disproportionately first-born friends, I find we're on the same wavelength. But I know I'm pretty unusual, both in general and among first-borns, so I'm cautious about extrapolating my own experience in that regard.
I’m an only child and all my closest friends were either first borns or oldest siblings, or had a much older sibling who was out of the house by the time we met. And even weirder, all our moms had us when they were 38 years old. I subconsciously gravitated toward a whole set of only children born to mothers exactly the same age as mine. It was pretty unusual to have your first kid at 38 in the early 80s, and we didn’t realize we had that in common until years later. I still think that’s kind of wild.
An explanation of the birth-order effect diminishing with age gaps, which still makes the primary driver of the effect parental attention, could be that the first couple of years of a child's life are the ones that require the most parental attention. A second child who is two years younger than their older sibling will get less parental attention than a second child who is six years younger, because in the first situations, the parents are having to deal with a toddler.
I think I was in your "several biological siblings, no social siblings" group, because of the large gap between my older sisters and me (fourteen years). I've often thought I got the best of both worlds growing up. In terms of parental attention, it was like being an only child, but my parents were still experienced parents, and knew what they were doing because of my older sisters.
Yeah, speaking as the youngest child, with a 12 year age gap between my youngest sibling me, your explanation seems pretty obviously correct.
The driver might be parental mental clarity rather than parental attention. Attention from a worn-out parent is of a different quality. Five minutes with a clearheaded parent can be more beneficial than hours with a distracted & frustrated one.
Yes, but the attention a toddler get would still be diminished by having an infant sibling. We would have to compare firstborns with short birth year gaps and see whether they do worse than firstborns with long birth year gaps.
> One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower? If it’s about having quality time alone with Mom, someone with a sibling one year younger than themselves only got one year of quality time; someone with a sibling five years younger got five years. But it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one. Either the first year is very important, or I’m missing something.
The lived experience of parenthood makes it pretty obvious why small age gaps have larger effects. The mother of a newborn and a 1 year-old has less attention to devote to the newborn, because the 1 year-old is extremely needy. A mom who read dozens of books aloud daily to the firstborn 6 month-old probably reads zero to the second born at 6 months if there is also a toddler in the house. The newborn gets a lot more of Mom’s attention if the sibling is a 5 year-old able to feed herself, use the toilet herself, play without needing Mom for more than ten minutes at a time, etc.
What about the first grandchild effect? On stage always.
My theory is that the average intelligence of the other family decreases for subsequent children. The first born interacts with two adults; the second born interacts with two adults and a child.
Yes and grandparents.
I have one immediate reaction to these questions.
Hypothesis: "Firstborn" children are recuited as deputy parents when younger siblings come into the family.
I speculate: Consciously, or unconsciously, the oldest feels more like an adult from that point on, and may feel and behave more responsibly, and also may enjoy feeling more "accepted" by their parents into the world of adult society. Maybe younger children never feel this (although families where i.e. the oldest girl ends up with lots of maternal responsibilities are anecdotally common.) Maybe younger childen have a kind of extended childhood vs an "accellerated" childhood for first-borns.
On the same topic, research published ~5 years ago looked at athletic achievment by siblings in US professional sports. (link below...I think, it seems not to be showing up...) They found a HUGE positive effect for YOUNGER siblings, especially the second child in a family. (Note: this study had vastly more male children and brother-brother pairs, for obvious reasnos, but IIRC the effects were just as strong for the few female athletes in their study.)
Several reasons were posited, the two salient ones were:
-- Practice effects: The younger child is often playing with the older, and with other kids several years ahead, this is very tough competition and an intense learning environment.
-- Parental / Family experience: Parents learn how to navigate schools, leagues, coaching, sports-bureaucracies in general, and the younger kids get fast-tracked into the best opportunities.
For me, the absurd number that stood out was this: In US Baseball, 700 (!) pairs of brothers have played in MLB. The younger brothers, collectively, attempted 10x more stolen bases than the older.
https://fivethirtyeight.com/features/why-are-great-athletes-more-likely-to-be-the-younger-siblings/
I definitely observe more athletic inclination in my younger daughter than in my older - starting with the age of walking, and propensity to climb, and comfort with climbing. I attribute it to two factors, besides innate proclivity: the older one was heavier as a child and maybe that's why she started walking later; the younger one was also on the ground a lot more and held less, because I had two close together - so perhaps she got more practice and therefore started crawling and walking earlier.
On the flip side, the second is less verbal and started talking and singing later, and is less of a communicator than her sister was at that age. This can be attributable to talents but also to having had less focused conversation time from me, while the first one got it from a full-time caregiver while I worked.
I agree. First borns seem to have very good verbal skills. What about the stage effect. The first born needs to put on a good show for parents and grandparents. First borns had to negotiate with parents to get what they wanted and converse with adults more often. More practice verbally for keeping their parents together, working, so they can send them to college.
Having an older brother with marginal Major League potential would probably be the best upbringing possible for a future baseball star. I knew a Cy Young award winning pitcher who was a third son in a much admired athletic family. His nurture was ideal. His father was a successful lawyer and the best Little League baseball coach around: a terrific guy. He had two highly athletic older brothers. His oldest brother had been an All-Southern California second baseman and played at USC, and then was his youngest brother's high school baseball coach. The older brother protected his younger brother's potential. When the athletic director wanted his star pitcher to start on two day's rest in the Southern California semi-finals, his older brother as his coach blocked that at some cost to his own career. "I'm not going to wreck my brother's career to win a game."
Big time sports are so competitive these days that
Relatedly, Seth Stephens-Davidowitz's new book "Don’t Trust Your Gut: Using Data to Get What You Really Want in Life," has a chapter on sports performance. Identical twins are more common in sports like track and basketball that require some innate skill like sprinting fast or being tall and less common in baseball, where success seems more unfated, being determined among pitchers to a large extent by arm health, while hitting a baseball seems like more of a knack than a phenotypic trait like height or speed, if that dichotomy makes any sense.
Here's my review of Stephens-Davidowitz's book:
https://www.takimag.com/article/this-sporting-life/
Thomas Sowell talks about this in "Discrimination and Disparities". Here's what I highlighted in that chapter:
'A study of national merit scholarships, for example, found that, among finalists from five-child families, the first-born was the finalist more often than the other four siblings combined. First-borns were also a majority of the finalists in two-child, three-child, and four-child families. If there is not equality of outcomes among people born to the same parents and raised under the same roof, why should equality of outcomes be expected - or assumed - when conditions are not nearly so comparable?
Such results are a challenge to believers in either heredity or environment, as those terms are conventionally used.
IQ data from Britain, Germany and the United States showed that the average IQ of first-born children was higher than the average IQ of their later-born siblings. Moreover, the average IQ of second-born children as a group was higher than the average IQ of third-born children.
A similar pattern was found among young men given mental tests for military service in the Netherlands. The first-born averaged higher mental test scores than their siblings, and the other siblings likewise averaged higher scores than those born after them. Similar results were found in mental test results for Norwegians. The sample sizes in these studies ranged into the hundreds of thousands."
(...)
"Consider how many things are the same for children born to the same parents and raised under the same roof - race, the family gene pool, economic level, cultural values, educational opportunities, parents' educational and intellectual levels, as well as the family's relatives, neighbors and friends - and yet the difference in birth order along has made a demonstrable difference in outcomes.
Whatever the general advantages or disadvantages the children in a particular family may have, the only obvious advantage that applies only to the first-born, or to an only child, is the undivided attention of the parents during early childhood development. "
They also have the attention of grandparents and practice verbally negotiating with parents. Who rules the family? Could be the first child.
Dr. Sapolsky mentions this exact phenomenon in a lecture series on human behavioral biology. The data discounts fetal resource depletion and parental attention. He indicates that the current working hypothesis is that the firstborn is forced into a tutoring or mentorship role.
Here's the relevant clip (can't remember which lecture it's from): https://www.youtube.com/watch?v=lj4D5haCkkQ
Here's the full series: https://www.youtube.com/playlist?list=PL848F2368C90DDC3D
Edit: double posted the series link, fixed.
Second edit: The full lecture link is included in the clip, 8. Recognizing Relatives.
Thanks: I do like listening to Sapolsky!
Hey, I'm one of those edge cases. I'm the oldest of two siblings, but my mother gave a child up for adoption 8 years before I was born. And I'm a classic older child, so one point for some sort of social vs. biological effect.
My guess would be that the difference is variance. Two populations with the same mean will be measured to have the same mean. This is often interpreted as no difference. However, if the standard deviations are different, the tails will look very different. In this situation, that would mean that first born have higher variance. Has anyone looked at the negative end of the spectrum? (As a reader, I’m obviously designating my end of the spectrum as the good side.) what’s the birth order like in prison populations?
Maybe it’s all the criminal-minded firstborns. The later siblings are too wary to get caught.
Just kidding, it’s a good question.
The one study I've found so far on criminality doesn't support this higher variance explanation. Sanni Breining et al., 'Birth Order and Delinquency: Evidence from Denmark and Florida' studies children from Florida and Denmark.(https://www.journals.uchicago.edu/doi/10.1086/704497 - no paywall at https://mitsloan.mit.edu/shared/ods/documents?PublicationDocumentID=6122)
Abstract:
>Despite large environmental differences between the areas, we find remarkably consistent results: in families with two or more children, secondborn boys are 20%–40% more likely to be disciplined in school and enter the criminal justice system than are their firstborn male siblings.
Main results (excerpt):
> While we do not find the primary mechanism that results in the higher delinquency outcomes later in life, we do find relatively precise zero results on some of these measures. On others we find decreased direct parental investment in the form of time spent with parents in favor of indirect investment in the form of formal childcare arrangements. Whether and how these differences could affect observed later life gaps is an open research question. This leaves us with parental investments within the home (as opposed to time out of the home and in the labor force) and sibling influences as our leading explanations for the birth order results.
Conclusion (excerpt):
> We find no evidence that second-born children are less healthy, and indeed second-born children appear to be healthier at birth and have lower rates of disability in childhood. We also find no evidence that parents invest less in second-born children’s education. These children attend no-worse schools and are more likely to attend pre-kindergarten. We consider differences in parental attention as a potential contributing factor to the gaps in delinquency across the birth order. Second-born children tend to have less maternal attention than do their older siblings because first-born children experience their mother’s maternity leaves and temporarily reduced labor market participation both following their own births as well as following the birth of the second-born. Therefore, in addition to the fact that first-borns experience undivided attention until the arrival of the second-born, we discovered that the arrival of the second-born child has the potential to extend the early-childhood parental investment in the first-born child
One of the coauthors elaborates on the vague 'sibling influences' cited above (https://www.npr.org/2017/07/04/535470953/research-shows-birth-order-really-does-matter):
> The firstborn has role models, who are adults. And the second, later-born children have role models who are slightly irrational 2-year-olds, you know, their older siblings. Both the parental investments are different, and the sibling influences probably contribute to these differences we see in labor market and what we find in delinquency. It's just very difficult to separate those two things because they happen at the same time.
In other words, maybe the first-born is a worse role model than the parents.
This is interesting. I am wondering about the effect of parental worsening alcoholism/addiction/domestic violence on children by birth order.
The people I know who were drinking/using with their parents tended to be the younger ones or youngest of several. Possibly the older/oldest get out of the house before it gets too bad but the younger ones are stuck in it (unless divorce or the state separates the family.)
This might influence criminality due to the association with addiction.
Total non-sequitur but I've noticed the more elevated the habitat of a species is- the more likely they are to be polygynous
sample size himalayan marmots, Tibetans, and some birds?
this is mostly joking but also not
Apparently, polyandrous beings seek out higher altitudes?
Maybe the likelihood of the husband meeting with an accident increases the higher up the mountain you go.
If you’re going to end up with 5 husbands eventually might as well start it at the beginning rather than waiting for #1 to fall off first.
I thought Tibetans were traditionally polyandrous?
I totally meant polyandrous sorry! Also birds actually don't fit in at all- just ignore everything
>One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower? If it’s about having quality time alone with Mom, someone with a sibling one year younger than themselves only got one year of quality time; someone with a sibling five years younger got five years. But it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one. Either the first year is very important, or I’m missing something.
An older sibling one year older is always doing fresh things, and their one year younger sibling is always just redoing the thing that just happened- there is no novelty, less enthusiasm etc. With a greater age gap, the older sibling naturally ages out of intensive parenting at some point during the younger sibling's development and the younger sibling gets more attention, i.e. older sibling goes off to college when younger sibling is in 7th grade, younger sibling is now effectively an only sibling.
Sounds reasonable to me. My elder brother, god bless him, went off to university when I was still in diapers and here I am. His adolescent parties might have increased my weirdness but that's speculative.
Making my first comment because I have actually thought a lot about this lately. Some anecdotal data to introduce my own theory.
My buddies from school are all very analytical, competent, and successful. Three stand out and they are all firstborn. They also stand out because their younger siblings struggled more and were more rebellious. Add to this general trend a half-exception: my brother and I.
I am a twin. Technically, I'm younger, but I have always been more academic and I was the first one to read, so I was the one who started with a natural advantage. My brother has indeed been "more interested in excelling in areas other than school, like trying to cultivate a special talent that the firstborn [or in this case younger twin] doesn't have." I still remember crying when I realized I wasn't as musical as him and he is now a composer, yet alas, not a frequent reader of ACX.
So here's my theory: older siblings start off with a natural advantage in intelligence. So similar to your second theory (in twins that advantage is decided more randomly because they are otherwise so "identical"). However, younger siblings don't immediately start to differentiate themselves. Instead they are PRESSURED to match the performance of their older siblings. Some of them just can't compete and rebel. They are then led away from traditional marks of success. So even if they could have succeeded in school just as well, they are discouraged from making that their priority because they feel they will never be as good as their older sibling. I still remember the tough fights about grades and music school that my brother and mom had, and I was mentioned way too many times.
Also if there is more distance in age, there is less pressure; their lower performance is more expected since they are so much younger and "eventually they'll catch up." This explains why there is a stronger effect for one-year gaps than five-year gaps. The gaps between my friends and their younger siblings are between 1 and 2. In our clique there are also younger siblings, but they are much further apart in age. These exceptions are the way it SHOULD work: younger siblings aren't constantly pressured into feeling naturally inferior and instead they can just learn from the successes and failures of the older sibling.
Finally, you mentioned that twins are underrepresented among your readers and also receive less attention from their parents. Well my mom gave both of us a LOT of attention as kids, so here I am.
All I can say is the middle child is best.
What if the actual effect isn't intelligence, but being antisocial? Could it be that siblings with less time with another kid in the house had more introversion or more non-social pastimes, like reading or computers? I think this is a more direct match to the data. This also predicts that only children should be overrepresented; I imagine this is easy to check. I would also be surprised if there wasn't a question about introversion to compare to, though I don't know if a baseline is easy to find.
Another good question
I should consider that a marginal influence. Given that "being antisocial" is low conscientiousness with low agreeableness, that's not what I can recognise in ACX readers so far. And families with such traits strongly around probably don't foster academic achievement of any kids, first, second or whatever.
I think they were speaking more in the "colloquial" sense of antisocial which is really more like introversion/awkwardness than clinical anti-social behavior (he mentions introversion in the next sentence which makes me fairly certain of this but I could be wrong).
Yes, I did not mean antisocial in any technical sense; just as in pursuing hobbies that do not inherently require other people around.
All speculation based on my own experience as an apparently exceedingly average ACX reader (late 20s, male, white, first born, programmer), but my guess would be that younger children consistently demanding more attention from parents socially conditions older children, especially first borns, to have a figure-it-out/do-it-yourself mentality (higher conscientiousness and industriousness?), which leads to a higher representation in your readership.
It tracks with my own experience that I was more independent and self reliant earlier due to the attention my parents needed to give to my younger siblings, and i think both a high delta in attention % between siblings after a younger sibling is born and the absolute difference in attention % may play a role, in addition to things that other commenters have mentioned like playing 3rd parent.
Interested in others opionions and experiences here, there should be a few other first borns in the comments, does this track for you too?
Every time this comes up I consider commenting, so I guess I'm commenting this time.
A few years ago, my mom (a PhD in developmental psychology) was observing my nephews and said offhand "it's so hard being an oldest child. You have to do everything first."
I asked her about that (being her oldest child) and she pointed out that younger siblings can watch their older siblings, and especially in early childhood, this gives them a lot of information on things like "if I throw a giant fit, what will happen to me?" And "how long can I get away with something before mom and dad notice?" And even "will I grow up? How long will that take? What will happen?"
Oldest siblings (and only children) are pushed to take on new ideas and experiences, that's just how the world works: you start with very limited data and figure it out yourself.
Younger siblings can, if they choose to, observe the results their older siblings got and coast, or at least use that data to limit their options.
So it makes sense for older siblings to be reading blogs about new ideas, technologies, and perspectives. The younger siblings out there will wait to see how it turned out for us before they get into it.
This is the exact story my mom’s siblings tell. My mom was 10 1/2 months (!) older than her sister, with two brothers several years younger. This was back when corporal punishment was common. The girls always said their parents “never disciplined the boys”. But to hear the boys tell it, they watched their older sisters get in trouble, learned what made their parents truly angry, and knew how to stay just inside the line.
I think we were looking at it backwards. We were looking at this through the lens of, "why is the second born child less intelligent or why is the first born child more intelligent". I think it's worth checking statistically to see if a younger sibling makes the older sibling more intelligent. As in, having a younger sibling provides more learning opportunities from a fly on the wall perspective AT a level that is more easily comprehensible than the level that adults usually speak to their children, which is just outside of the child's current abilities. So, the hypotheses are, 1) having a younger sibling provides more easily understood learning opportunities without direct emotional cost of failure AND 2) a setting that perches the elder sibling in a relationship as an outlier with the potential to compound successes. So, we need to know what baseline IQ of only children are and see if the younger children are actually less intelligent than baseline or the older children are in fact made smarter by having a younger sibling.
Re #1, all the oldest children I know maintain the ability to deliver a smackdown on the youngers, in some form. The emotional cost of failure may actually be higher there.
True say, G. But, you're interchanging the emotional damage from my example to the younger party, although that could produce a difference.
#1 makes sense. I think I put some effort into staying ahead of whatever my younger sister was doing. Keeps the older one on their toes.
How do older siblings look compared to only children? Such data would be interesting here.
We would need a lot of data to make the comparison valid. Like parental education levels, age of parents at birth, socioeconomic status of household reared in, child's educational level, a valid IQ score, and lots of other things. Then after analyzing and controlling for the confounding variables we could make some further hypotheses. It would be interesting to see how they stack up though. Another interesting idea would be to see if there is a pattern in the personality traits between younger and older siblings, such as openness to experience that could inform us of potential cognitive experiential tendencies.
I like the quote in the first paragraph, "correlate birth order with things." I use to characterize this kind of psycho research as correlating things with other things, happy to find it here. Folks, please remember, correlations are rarely zero in non randomized groups, so this stuff is much less interesting than you think. Moreover, I think I recognize a pattern, that the author of this blog tries to please us by basically telling us, once in a month, how smart we are. Nah, I'm not.
And, of course, the obligatory call for "we need more research" in the end, like a plumber who wants to solve the world's problems with more pipes.
> Moreover, I think I recognize a pattern, that the author of this blog tries to please us by basically telling us, once in a month, how smart we are.
One wonders how much of a birth order effect there might be in the audience of birth-order-effect essayists. 😈
Did you read the post? I'm not doing correlations, and I'm not just finding that some correlation exists, I'm finding that the first to secondborn ratio is about twice what you would expect, in a sample of thousands of people. Recommend re-reading this and if you're still confused I can try to explain specific parts to you.
Not entirely. As I wrote, you had me at the correlations of things. But I have now re-read my own comment, and I must say I still like it 🤣
Iconoclast! Spot on, though.
Could it be reverse causation, that parents who have a especially smart first child are pleased and are more likely to have a second child whose ability reverts to the mean? Did someone do a comparison of all the first-born and second-born, whether they have siblings or not?
Second-borns without siblings? Elvis comes to mind...
1. Is there any difference between a two-brother pair and a two-sister pair?
Some older brothers really haze the younger one. Surviving that changes people. I’m not sure it’s entirely gender-based but I think that’s a factor.
> it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one.
The developing brain is particularly sensitive to stress in the first two or three years. Stress exposure modifies the HPA axis to cause a permanent increase in the sensitivity of the stress response. You can see the effect in this graph from (Essex, 2002):
https://ars.els-cdn.com/content/image/1-s2.0-S0006322302015536-gr4.gif
Transitioning from being an only child to being a sibling is an extremely stressful event, so you'd expect it to trigger that effect. Note that although we think of stress reactivity as 'bad', high stress reactivity is likely linked to later 'overachieving', as well as to a higher risk of mental health disorders in later life.
Another factor that may complicate things is childcare -- having a new baby probably affects whether the older one is placed in daycare. Center based daycare in particular is known to substantially raise cortisol levels. Cortisol rises are actually smaller for younger children (cortisol response hasn't settled down yet + lower bioavailability of cortisol) but the measured long-term effects on younger children are larger. So e.g. one causal study of universal childcare expansion of found
> this policy resulted in a rise of anxiety of children exposed to this new program of between 60 percent and 150 percent, and a decline in motor/social skills of between 8 percent and 20 percent.
See https://criticalscience.medium.com/on-the-science-of-daycare-4d1ab4c2efb4 for links to the supporting research on cortisol/childcare.
(Essex, 2002): https://www.sciencedirect.com/science/article/abs/pii/S0006322302015536
This is interesting. I’m wondering today about the effects of parental alcoholism/drug abuse/domestic violence on children by birth order.
Since those conditions usually progress and worsen, the older child has more minutes with a stabler parent. The younger one(s) may have the parent who is drunk twice as often/ten times as often and possibly more likely to drink with the child. To the last child’s detriment, in conditions the oldest escapes by already being out of the house.
Unless the parents divorce and the environment improves, in which case the youngers might get a healthier environment.
First child is more likely to have "high functioning" autism than subsequent children (yes, I know the autistic community doesn't like that term, but unless they can come up with a better one, I'll use it in inverted commas). One theory is that this could be due to elevated testosterone levels in the womb (which then decline for later children due to the fact that the poor woman has other children to look after, which tends to reduce testosterone levels). I would be very surprised if this wasn't associated in some way with the higher readership of ACX. Full disclosure: I'm autistic.
Could it be that younger siblings are more likely to mention the blog to their older brother than the other way around. Because when you're the younger one, you're always looking for things that the older one hasn't done before you. The older one doesn't feel the push. This could be debunked if you know how people came to the blog.
Older siblings are by definition older than younger siblings. If older people are more likely to read ACX (which seems pretty plausible) then that's going to be a major confounder.
I think, though I'm having trouble thinking about this clearly, that the entire set of older siblings in the world isn't noticeably older than the entire set of younger siblings in the world, except very weakly since some of the older siblings' would-be younger siblings haven't been born yet, and some of the older siblings have died off while their younger siblings are still alive, neither of which seems relevant to the ACX-reading age demographic.
There is a slight bias. Consider a simple model where all families have exactly two children, at a two-year interval, and everybody lives exactly 70 years. Then nobody gets to be an older sibling until they're two years old, so the average age of older siblings is 36; but the average age of younger siblings is 35. However, the average age of older siblings over two years old is the same as the average age of younger siblings over two years old. So you're good, as long as none of your respondents was less than two years old.
Isn't there also a change as birth rate increases or decreases? As in if birth rate is decreasing, there is a higher percentage of firstborns among younger generations?
Here's how I'm thinking about this. There is some median age at which a person is likely to discover/become interested in ACX. To take one example at random, I started reading ACX when I was about 29, so for the sake of example, let's call that the "cutoff age". The mean ACX reader is 33 (very close to my own age). All younger siblings who are 33 have older siblings who are also above the cutoff and so would be equally likely included in the sample of ACX readers, but many older siblings who are 33 will have younger siblings who are BELOW the cutoff age and so would be excluded from the sample simply by virtue of being too young to "age in".
You'll get SOME effect from this with only two assumptions: there's a de-facto age-in cutoff for ACX readership, and ACX readership is heavily concentrated close to that cutoff, which I think are both reasonable assumptions. I don't know what the R-squared of this effect is but I expect it to be non-zero, and it might be big enough that the question ceases to be interesting.
Here's another example to illustrate the concept: What percentage of retired Americans are the youngest sibling in their family? I have no idea but I'm willing to bet that it's disproportionately high, and that has nothing to do with birth order making you more likely to retire.
The effect from older siblings whose younger siblings are too young to read ACX is exactly counteracted by the effect from younger siblings whose older siblings are too old.
I don't see any theoretical reason to suppose there's an equivalent "age-out" for ACX.
There's always an age-out: if nothing else, there's death.
Note that I'm not saying that ACX readers regularly have older siblings that read ACX and then die. It's enough for the probability of reading ACX to begin with falls off with age until it hits 0. It must, because the probability of someone reading ACX when they're 1000 years old is 0.
I didn't say no age-out, I said EQUIVALENT age-out. Put the middle of the bell curve at 33. At 63, you're probably only slightly less likely to read ACX, but at 3 you can't read at all.
Assuming that older and younger siblings are no more or less likely to die at any age than each other, they should be equally represented at all ages. For people under 25 or so, some older siblings may be undetected older siblings, while no younger siblings are undetected, but if you look at currently living retired people, there should be precisely the same number of people who are the older of two siblings as who are the younger of two siblings (if we ignore whether the other sibling is currently alive or retired).
I don't think your first sentence follows.
I'm assuming a stable population structure, so that the number of first children born every year is the same, and the number of second children born every year is the same, and the number of third children born every year is the same, and so on. In families that have two children ever, there must be the same number of first children as second children ever. Given the stability of the broader population, this means that the number of (first children in families that will eventually have a total of two children) born any year should be the same as the number of (second children in families that will eventually have a total of two children) born in any year. (The difference in the number of first children born in any year and the number of second children born in any year is the difference in the number of families that eventually have a total of one child and the number of families that eventually have more than one child.)
If first and second children are equally likely to die at any given age, then my first sentence follows.
If a population is steadily growing at a 2% annual rate, that could mess things up (though it's not immediately obvious to me whether that will increase first children relative to second children or vice versa - though I think the size of the effect will just be 1.02 raised to the power of the average age difference between two siblings). If there are specific years in which families were more or less likely to have children (such as the reduction in childbirth during World War II and the covid pandemic, and the boom in childbirth after World War II) then that will produce an effect on birth orders whose direction may depend on precisely how many years ago that event was.
To whatever degree older siblings are older across the general population, we should expect it to increase the larger the age gap between siblings is, while the readership effect increases the smaller the age gap between siblings is.
I wonder if it is more subtle than just quantity of attention - it's quite exciting doing things for the first time with your oldest, teaching them things etc. but when you get to younger siblings, you feel you have already done whatever it is, and it is slightly boring so you don't bother quite as much - the novelty value has gone.
Even assuming an implausibly hard selection effect where all ACX readers have IQs and openness of at least 3SD above the mean, I can't get such an extreme skew towards first-borns. 64%, not 72%.
But it can certainly explain part of it. The first-born effects of IQ and openness are known, and known to be small (roughly 1/10th of an SD) but they show up more in the tails. If 1/10th is an underestimate (plausible for a few reasons), maybe we can go to 72%, but it's still an implausibly hard selection effect.
But what's the mechanism behind the IQ and openness effects? They don't show up in every culture (Botzet et al. 2021). The study major effects (Barclay & Myrskylä 2016) show up in Sweden, or I would have considered that perhaps in the US with the high cost of tertiary education, first borns are more likely to have their parents be able to pay for it.
> n <- 1e8
> bo <- rep(0:1, each = n/2)
> ops <- rnorm(n, 99, 14.98) + bo * 1.5
> iq <- 99 + 0.3 * (ops-100) + 0.95 * rnorm(n, 0, 14.98) + bo * 1.5
> cor(iq, ops)
[1] 0.3
> sd(iq)
[1] 15
> prop.table(table(bo))
bo
0 1
0.5 0.5
> sum(iq>145 & ops > 145)
[1] 2052
> prop.table(table(bo[iq>145 & ops > 145]))
0 1
0.36 0.64
8000 people took the survey. If they're selected out of a worldwide population of at least 250 million English speaking adults, that selection is 4 SD above the mean in whatever traits make people read and fill out surveys on ACX.
If those people are 3 SD above the mean on the traits affected by birth order(IQ, openness etc), that would imply a correlation of 0.75 with the traits that make you an ACX-survey-filler-outer(IQ, openness, conscientiousness?). Sounds reasonable to me.
By the way, when you say 1/10th of an SD, is that an average difference between siblings, or an average between first-born and second-born siblings? From Sandra Black's Swedish study, the difference between the first-born and second-born was the largest(illustration: https://emilkirkegaard.dk/en/wp-content/uploads/black1.jpg), closer to 2/10th of an SD in cognitive ability I believe.
Also, if you're 1/10th SD above average on IQ, and 1/10th SD above average on "personality", then you're more than 1/10th above average on a composite of those traits.
The 1/10th came from Rohrer et al. https://www.pnas.org/doi/abs/10.1073/pnas.1506451112
On the 2-sibling within family sample in that study(n=900), the difference was 0.17 SD on IQ. Table S2, page 25.
There are several samples in the study though and she gave 10% as the approximate overall effect. But yeah, could be a bit higher. Barclay also has 2.3 IQ points in a very large sample. It still doesn't get us to 72%, but it could explain part. I think Scott has IQ and openness data. I doubt >3SD selection is what he finds, if he has tests with norm data available (easy for SAT, maybe not for openness).
Let's say ACX survey takers are at least 4 SD above the mean on a composite "ACX survey taker"-trait as previously calculated. For older siblings to make up 72% of the people 4 SD above the mean in a trait would require about a 0.22 SD advantage in that trait.
If that trait is a composite of IQ and openness(or a composite of IQ and many relevant personality traits), then it would only require older siblings to be 0.16 SD(2.4 IQ points) above the mean in each of those two traits, assuming they both matter equally.
Maybe you know enough about birth order personality effects to rule out such an advantage in openness or any ACX-relevant personality composite, but otherwise it seems like decent explanation for the 72% older siblings to me.
> I additionally tried to compare two different types of social firstbornness - one where no older siblings lived in the house when you were growing up, and one where your parents had never parented another child. There weren’t many people discordant on these two measures (29 vs. 20 respectively), but for what it’s worth, the ratio was in favor of the first type.
I can't tell what this means. As far as I understand the terminology, the set of "people discordant on these two measures" unambiguously refers to every subject whose answers to question (1) and question (2) do not match. But that is a single set of people which cannot have population 29 and population 20. Who's in the group of 29? Who's in the group of 20?
> So for example, since the older sibling will always be smarter than the younger when they’re both young children
This claim can't pass a laugh test. How long did it take your little brother to be better than you at playing piano?
29 people said yes to A and no to B; 20 people said no to A and yes to B.
Great post, but I’ve got 3 kids and my immediate n=1 explanation didn’t really fit with your 2 suggestions. Seems to me it’s explained by the relationship dynamics of having a sibling but is NOT really to do with differentiation from each other. Young children who are 2nd siblings and relatively close in age to no. 1 seem to get a huge proportion of their social and intellectual development from the older sibling, regardless of gender and differentiation. I think that that close bond and dynamic reduces their drive to seek new sources of information (such as ACT) because the older sibling has such a strong influence in shaping their frameworks for viewing the world - even when they actively/ innately differentiate from the older sibling’s frameworks. In addition, the older sibling becomes accustomed to socializing the younger into their (older sibling’s) developing discourse. They are likely to feel rewarded/ fulfilled for this from the younger sibling’s receptiveness to taking in the info from them. This creates in aggregate a lasting disposition to seek new sources of info. Again, it’s easy to see that this may only play out within narrower samples, such as your readership, or with specific classes of info, but be lost at the general population/ broad context level.
My observation: The first child learns to be a boss by bossing around their parents first.
New parents want to be good parents and attend to their child, so they listen for what the child wants. They have time, attention and no experience at parenting at this point.
That first child can end up running the parents lives. And with that experience, any later children will be less experienced at being the boss and the parents will be more experiences at rearing children. But at the same time, the first child has already learned to dominate and doesn't like giving up that power. The second child might rebel and try to take a different path in opposition to the power of the older sibling, but a third or fourth child has to fit in some how. After all, the decision-makers, oldest child, parents and second sibling will make the rules.
Anyone care to comment on their observations of first child being the boss of the family?
My eldest son never seemed to want to be the boss of anyone. The second has been tougher but still very agreeable. The third can take responsibility alright. All wonderful guys.
Was there a strong decision-maker in the family? Someone has to do this job and I often see the first child doing it.
As the technically ‘middle’ child of triplets (ten minute age gap solely due to birth weight) this birth order research always seemed a bit silly to me, but I suppose that’s mostly because of my personal unfamiliarity with the phenomenon of sibling age gaps.
From what I remember (being the 1st, and completing fitting the findings: I read ACT, I am in STEM while my brother choose a more artistic path), we should not look at parent investment or anything parent related (which fit well with parenting generally having little effect), but at direct relation between siblings. We formed a 2-member gang with my brother, with the eldest (me) the natural and not challengeable (at least until we were both past 17) leader. I think it fits my model of genetic>peer>parent in term of relative influence on every psychometric, when peers are siblings and later friends/schoolmates. Your siblings are part of your peers, the most important or even only one before 6yo...
The only thing I find quite strange in the data is that I expected a huge difference between same sex and opposite sex siblings: The brother sister dynamic is very different than between brothers (among sisters I do not know because I have no direct experience nor first hand observation among my friend's families)
I think the differences between same-sex and opposite-sex sibling sets are much more minor in the early / preschool years, which are probably more formative.
good point. I do not have any sister, and among my friends I have observed the brother-sister dynamic only for older siblings, at 12y+ I would say....But now that my friends and I are at the parent age, for pre-school brother/sister, it's indeed more similar. This early they already have very different male/female interests but it's the oldest that is the leader, boy or girl. Still, given the diverging interests, I would have expected a larger difference....except if the key moment is really when the younger child have almost zero non-famlily interraction (before 3yo).
It's often said that all of the original seven Mercury astronauts were first borns or only children and 14 of the next 16 American men into space were the same. But I don't see a link to a study.
As a Catholic Baby Boomer, my being a (rare) only child was a big deal when I was a kid in the 1960s. My friends assumed I got more presents on my birthday than they did (which I probably did). Adults were always telling me I was emotionally deprived by not having any siblings (which I probably was)
Now that only children are common, I never about them anymore.
Maybe for many younger siblings, if they do nerdy things at home, they get teased by their older sibling. And then "not being a nerd" might become part of their identity. But IQ other major life stats stay the same. This hypothesis would weakly predict that male dancers are much more likely to be older siblings.
Except the phenomenon being explained is that older siblings are nerdier on average. Why would nerdier older siblings tease their younger siblings for being nerdy?
They wouldn't; in sibling pairs where both siblings are prone to nerdiness, they'd both end up nerdy and both read ACX.
In sibling pairs where only the older sibling is prone to nerdiness, the older sibling is just fine being a nerd.
In sibling pairs where only the younger sibling is prone to nerdiness, the younger sibling gets teased out of it by their older sibling.
Say, for example, 20% of older siblings are nerdy compared to 5% of younger siblings. So up to 80% of the time, a younger sibling would get teased for nerdiness. Whereas if a younger sibling tries to tease an older sibling, the older sibling rolls his/her eyes.
It seems kind of strange that the focus is all on intelligence and academic achievement. The effect of birth order on readership of this blog (71/29) seems to be much stronger than for physics laureates (60/40) . While we might like to think that reading ACT is as good a proxy of intelligence as a physics Nobel, it suggests to me that it's a more specific personality trait that first-borns tend to have that correlates with attraction to a weird rationalist blog.
Perhaps the trait of thinking that reading an intellectual blog is a proxy of intelligence
I don't think so, dumb as I am. Still I like the culture here. Wouldn't care to join MENSA and probably wouldn't qualify any more. Still unsure about joining any club that would have me, like Groucho Marx.
An interesting birth-order sports anecdote is Fernando Valenzuela, the Los Angeles Dodgers baseball pitcher who caused a sensation in the early 1980s. He was the youngest in a family of 12 in Mexico. He had one of the dumpier bodies you ever saw on a famous athlete, but was a baseball genius.
His older brothers were ardent baseball players too, but they had to go to work when still young. But Fernando was the adored baby of the family and was allowed to do nothing but play ball.
A possible overlooked confounder here is age. I'm 19 the oldest of 4. My younger siblings aren't at the age where they'd understand ACX.
As for your average 33 year old ACX reader you can suggest that many of your readers came on board in the Golden age of blogging ~10 years ago when their siblings were too young to come on board.
Interesting point. Previous attempts here to work out the age effect have assumed a uniform population size. In reality, global population is increasing, leading to a greater likelihood of someone being "not old enough" than someone being "too old". But if it's a subpopulation that's both rapidly growing and just coming of age, this could have a big effect.
*edit* Never mind. There would have been firstborns too old to join the subpopulation.
Considering that people too old to come aboard are more likely to be first-born, shouldn't this all more or less cancel out?
Is there some "recommended" way of sharing analyses? I'm curious about the the bio/social split, if I find something interesting I'd like to share.
I'm looking into it because I was a bit confused by Bucky's part about the biological vs social effects. If I get it right, the point of their selection (bio > 0, social = 0) is to filter people who had biological siblings at some point, but currently have none? I get that this would "isolate" the purely biological effects, but it also seems to introduce all kinds of other biases (it's not really representative of the general population) and additionally it doesn't even mean that there were no social siblings *at a previous time* in which it could have had an influence.
(btw the link to the CSV file in the old blog seems to be broken, excel file is fine)
I think it's explaining vs. imitating.
Of my three kids, each 21 months apart, the younger two strongly tend to do what their older siblings are doing. They learned early on that to imitate is usually a good choice, so they do it a lot and it serves them well. The oldest imitates adults of course, but not nearly as automatically, because she knows many things we do she cannot or is not allowed to do. What she does do, however, is explain things to her younger siblings and give them instructions. That's what she got from us and it's harder than imitation but I think she has learned to think in that way.
None of them are in school yet, but I expect the oldest will find explanation-heavy subjects like math and physics slightly more intuitive than imitation-heavy subjects like music and physical education, and maybe her younger siblings will tend to go the other way.
Of course the ratsphere is super into explanation and I would argue it grossly neglects imitation. When we try to persuade, we try to craft excellent explanations, rather than build shiny role models to champion beliefs we want others to share. But much, arguably most, of human learning in the general population happens through imitation. Especially on ethical matters.
Good point, that fits what I remember from my younger brother and myself childhoods...
Could sleep disturbance in infancy be an explanation? When you are the firstborn, your parents try very hard to avoid waking you up, and you enjoy uninterrupted sleep. When you have a toddler sibling, you get waken up all the time. If uninterrupted sleep is important for infant brain development, it would explain why the effect disappear as age gap increase (a 5 year old can keep quiet, a 2 year old can't), and it would explain the twins (twins wake each other up all the time).
Maybe - I have thought one of the strongest determiners of infant sleep is whether they are hungry (the secondary one being when the baby wets its diaper and wakes itself up.) In the first few months when the baby has to eat/nurse/be fed every 2-4 hours, it’s challenging to get any sleep and so the “don’t wake the baby” goal is so the parents can a) sleep themselves b) ever do anything other than baby care.
There might be a sweet spot of maximizing sleep and nutrition both, leading to best brain development. Babies who are difficult to calm do have a higher incidence of bipolar when older - maybe they don’t get enough sleep-based neural pruning (whatever that’s called).
Hypothesis: the ideal path for early brain development and interest in abstract ideas is:
- you have smart parents
- they spend 1-2 years with you at the center of their universe, talking to you to build vocab, reading to you, maybe fussing over your nutrition
- for the rest of your childhood they spend more time with your younger sibling(s) and leave you alone with lots of books
Supporting evidence: firstborn children are somewhat more likely to have poor vision
https://www.discovermagazine.com/planet-earth/why-more-firstborn-kids-need-glasses
That's an interesting thought, but are only children underrepresented relative to oldest siblings?
Yeah, that is an implication and I should have thought of that. I don't see any discussion about only children in either post, in part because of controls (only children would tend to have more educated parents, so they could be overrepresented here even if the hypothesis is correct) and because the % of only children has increased over time (and is different in different countries).
Could there be some selection effect (at least for ACX readers)? Readership is smart and in an age range such that a smart older bro also reads ACX but the smart younger bro does cooler other stuff(?) Accelerating change of internet, older generations more similar than newer, I dunno.
I guess I'm an aberration. I wasn't around for Slate Star Codex, but I read this blog. I am the third of three siblings in order of birth. I know for certain that one of the others doesn't read this blog because he's dead, and I doubt the other one does because he's not a big blog reader and mostly not interested in even the wide variety of subject matter covered here (if you start covering the NFL and military matters a lot, he might notice).
Eh, I'm the 2nd of 2 and I don't think my brother reads ACX, despite being smarter than me. "Exception" might be a better word than aberration.
Side note, I wish Scott had included families of 1 child in his analysis. Maybe that would have thrown things off or been more complex; it's just that I'm curious. Rumor tells me only children are "like oldest children only more so," and I'd really like to know how likely this is to be true, since I have an only child.
I think the reason he didn't is that he only has data from people who do read SSC.
Though I suppose you could compare "portion of the general population who are only children." with "portion of the SSC/ACX survey respondents who are only children." (maybe controlling a bit for age or other factors?)
I think that Caplan and others tend to overstate the results of the research he presents. I don't remember the effect sizes of the top of my head, but I think his data indicated that something like 1 SD "better" parenting led to 2-3 point increases in IQ. This is a much more modest effect than most people's intuition, but still significant, especially for tail outcomes.
The social sibling effect could easily raise the IQ of first borns by a couple points, which is going to lead to noticeably skewed ratios for the tails. If, among well educated parents, the average 1st-born IQ is 114 and 2nd-born is 110, then among IQ 140+ individuals who are 1st or 2nd born, 65% will be 1st born.
At least for Nobels, etc., I'm going to blindly guess it's the differentiation thing.
I know both me and my (younger) brother were absolutely determined we weren't going to do STEM related stuff because our dad was an accomplished programmer and adopting his profession in a world of infinite choice felt somehow medieval.
But it turns out genetics is strong. We're both garbage in our chosen careers because young folks stink at choosing careers. But we've both managed to fall into that kind of work later in life.
In a family that was more traditional (as I gather traditionally successful folks' families tend to be), I would have been pressured into my dad's profession (and inherited his business contacts) while my brother would have had to work something else out.
Do I think that's a recipe for general success in a typical family? Force your kid to do what you do? Absolutely not.
But when talking about people who perform at the very top of their fields, probably genetics and nurture both have to be moving in the same direction. And really you can only do that kind of intensive training with one kid, and probably you pick the first one.
It's a tough course to steer. Forcing children into anything isn't going to go well, but seeing that Tommy has talents for X and ushering him along the path towards a career in X is different.
There is so much cultural pressure built up around the eldest son to be the bearer of the family heritage, even if that is relieved a lot in modern Western society, that it's hard to say. Take Leo Varadkar, who is an Irish politician and in government at present. Father a doctor, mother a nurse. Two older sisters - doctors. He's the third child and only son. Trained and qualified as a doctor, then went into politics.
There is a huge (n=4 million) paper showing birth order effect is real for homosexuality: https://www.tandfonline.com/doi/abs/10.1080/00224499.2021.197433
Also a new paper about IQ & birth order finds effect even controlling for family size (which is important because it was said family size-IQ relationship produces the IQ-BO statistical artefact):
https://journals.sagepub.com/doi/abs/10.1177/0146167212445911
These imply pre-natal environment IMHO
Oh sorry, I meant to link this one: https://www.nber.org/reporter/2017number4/new-evidence-impacts-birth-order
There's a plausible-sounding medical explanation for Ray Blanchard's finding of why younger brothers tend to be modest more likely to be gay than older brothers involving repeated exposure to male hormones in fetuses affecting mothers' gestational environment.
I'm wondering whether the apparent effectiveness of the English system of primogeniture -- the oldest son will inherit the lands and the huge house and the seat in the House of Lords while the younger sons will go into law, church, Navy or Army depending on their specific characteristics -- might be tied into this. Perhaps oldest sons tended to be less variable than younger sons and thus made slightly better heirs and landowners?
Racehorses - (horrible link) https://books.google.co.uk/books?id=S36O25M_6C0C&pg=PA187&lpg=PA187&dq=dam+racehorses+birthrank&source=bl&ots=-vtkJF1JqB&sig=ACfU3U324rsEAPGPvy9qfjcauefenactBw&hl=en&sa=X&ved=2ahUKEwiOz_SToJL4AhUfQEEAHYneCPc4ChDoAXoECCEQAw#v=onepage&q=dam%20racehorses%20birthrank&f=false.
Gives tables from work carried out by an E J Finnochio, that the birth order (or rank) matters for the racing success of the foal. And that the age of the dam is less important.
It seems like there is an assumption being smuggled in here, namely that “reading SSC is correlated more with intelligence than some other trait.”
What if that other trait is, say, conscientiousness, or being thing-vs-people oriented?
Like, what if older siblings are less likely to be as people oriented because they didn’t have someone a few years older than them as one of the most interesting, salient features of their environment?
I’d love to see if the “first borns are overweighted” thing is true even if you filter out people who put themselves on the autism spectrum. That’s the approach I’d be taking - I’d try and find subsets of the data where the trend dissappears.
FWIW in the 4th of 9.
I like that.
This is only slightly related, but... Do first-borns tend to partner with first-borns? This is a trend I've noticed in my family and wondered about before. If there is some set of characteristics associated with being the first-born, it could be that people with a lot of those might be attracted to other people with a lot of those as well. This could explain not only my observation but also why these people clustered together as this blog's community.
With infinite resources, we could also survey a whole university, say, and see if people's chosen major has predictive power over their birth order. I think someone already mentioned this, but I get the feeling first-borns are more likely to be pressured into studying something traditional and "safe" than their younger siblings.
Nowadays nearly half of people are first-borns. To check that up, one has to look at times when there were 11th borns. I don't see a trend of first-born-attraction in my genealogy but that is much too little data.
n = 1: I am the oldest child of two oldest children, with hereditary Asperger's added to the mix.
What about the likelihood of finding only children in your sample? If hypothesis 1 is true, we should observe more only children when controlling for the relevant variables (that is, considering that only children are possibly more likely to come from unmarried couples, short marriages, etc).
Some people commented on the possibility of a "mentoring effect" for first-born children. If only children aren't more likely to appear in the sample, then that hypothesis could be more likely.
I also think about other variables that are not related to intelligence. Like some readers mentioned, the likelihood of the older sibling finding more introspective hobbies. I also consider the likelihood of the younger sibling learning how to be more "charming" and social in order to get more attention and differentiate himself from the always older and more intelligent sibling.
"One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower? If it’s about having quality time alone with Mom, someone with a sibling one year younger than themselves only got one year of quality time; someone with a sibling five years younger got five years. But it looks like the birth order effect is stronger for someone with a one-year-age-gap sibling than a five-year one. Either the first year is very important, or I’m missing something."
Babies and toddlers are higher-maintenance. If the older sibling is already seven or eight when a new baby arrives, the baby obviously has more pressing needs, and the parents will in fact switch tracks to doting on the baby, possibly growing somewhat neglectful of the older sibling. Also, a much older sibling is old enough to, themself, help care for the baby, which will help smooth things over; a two-year-old is pretty useless (and sometimes actively harmful) around a newborn.
Yes, this. Plus if the older sibling is old enough to be at school, then the baby is effectively a firstborn for six hours a day - both in the positive sense that they get more 1:1 parental attention and in the negative sense that they don't have a close peer to play with and imitate.
"a two-year-old is pretty useless (and sometimes actively harmful) around a newborn."
Aha, yeah. I nearly gave my mother a heart attack years back, my younger sister was born when I was two, so when she was about six months or so (EDIT: maybe she was a year old, so I would have been three) my mother put her out in the garden in the pram. She started crying, so like a good Big Sister I took her out of the pram and carried her indoors. She was slipping out of my grasp but I managed to grab her like a parcel, more or less. When my mother saw me proudly carrying her in (with a shaky grasp around her middle), she lunged to take her from me 😁
I was five when my younger brother was born, so I was more helpful and less dangerous then!
My explanation is that first children are required to take the lead on a whole host of situations where the siblings are involved. By taking the lead, out of necessity more often than not, the other children are relieved of that duty. That trains the younger children to be followers and the older children to be leaders. This explains why children a few years older create a stronger tendency, and also why after seven years it drops off - too little difference makes it less obvious who is in charge, while too much difference reduces interactions.
Why does this affect ACX readership? I think this blog interests people who are trying to figure out the world and make decisions about practical and moral effects. For someone who thinks that's important, there's a clear reason to follow the blog. For someone trained to let others do that work, then there's much less reason to follow a blog like this.
I’m an older sibling but I can’t imagine my younger brother, who has a higher IQ, earns more and is generally more successful, taking an interest in this blog. I tend to experiment a little more, have wider interests and deep dive into obscurity whereas he does the normal stuff very well
Wild. The one trait psychologists agree is known to be causally influenced by birth order (male homosexuality) is the one most accepted to be biologically and not socially caused?
The potential social mechanisms get creepy quickly.
Correct.
They looked for the birth order effect in boys with older adoptive and step brothers, and did not find it. That is why it's accepted as 'biologically' caused. However, a recent study challenged the birth order effect as a statistical artefact, so it looks like there's no nurture effect either.
I thought the study was pretty persuasive, which if correct, means that this mystery has even fewer clues than it did before.
" Firstborns get more quality time with their parents during the first few years of childhood."
I am puzzled. You seem to have an assumption that reading SSC makes firstborns better in some sense. But maybe it is something not-so-glorious that happens because the firstborns get more undivided attention of their parents: I can imagine the undivided attention makes them prone to navel-gazing and overestimating the extent their personal subjective experience and thoughts in general are super special and important and worth of loudly explaining to everyone around? Or, in other words, increased interest in philosophy (edit, and lets be realistic, strong political opinions)
The effect would be then naturally strongest in people who were the only child in the family. Eldest sibling has to learn to share when the siblings are born.
Does the data show there are more SSC readers who had no social siblings, compared to overall amount of them in the respective age cohorts?
EDIT. I didn't have siblings.
What we need to do is link up the birth order data with the (self-reported) mental illness/psychological problems data and see how that stacks. I think many of us are somewhere on the autism spectrum or thereabouts, so niche interests, obsessiveness, and wanting to talk about our pet subjects at length and in detail all go along with that.
Plonk us down in a group of the like-minded who will pay attention to what we're saying, argue back, and talk about *their* pet subjects at length and in detail, and who won't be "don't you have any *normal* hobbies like going out to bars to have fun, pop music, and movies?", and we have our little acre of paradise right here.
Eldest sibling does have to learn to share but eldest sibling also often gets landed with the caretaker/teacher role, e.g. "help Jimmy with his maths homework; did Susie change her dress?; set the table for tea and call your siblings in" etc. so being bossy and lecturing are habits you pick up.
" You seem to have an assumption that reading SSC makes firstborns better in some sense."
He has data showing the SSC readers are disproportionately educated, technically-minded and high-earning.
"Overestimating the extent their personal subjective experience"
What does this mean, exactly?
I'm really surprised that this (IMO very weak) conjecture is getting a pass:
"Given that readers of this blog are highly-educated (about 37% have masters or PhDs) and mostly in STEM (41% programmers of some sort), plausibly birth order affects something about intelligence, education, or STEM orientation"
I didn't take the survey. Did you ask if the siblings have advanced degrees or work in stem? Have you directly addressed the possibility that older siblings might just enjoy reading blogs more? Or as another user points out, be inclined to take surveys more? Or spend time on using the internet more? Or any number if other factors?
He has an entire blog post about your questions ;-)
He is merely referencing previously established "knowledge"/information ...
I guess I am the only woman and mom here and oldest daughter of a line of oldest daughters, and I had to smile a little because I never bullied my younger siblings: in fact in many times I was their mother and nurturer when I had to babysit for them. Now my sons.. well I see what you are talking about: though i always encourage them to get along: it was the second son who was the bully if any of that went on.. well gotta go.. yes. that is just our little story: circumstances vary.. have doctor's appts. today.
There's at least one other woman, mom, and commenter here. I might point her at the thread.
Correction: there are at least two :)
Cheers! Another.
Another mom here. 5! What a sample.
I believe I am said mom. Hi!
There may be as many as several of us women on here! I don't know about how many mothers, though.
Again, it probably is that girls get steered (pushed into?) the mothering role, also depending on how many younger children; certainly, for our 5+ families, the division of labour with the eldest daughter taking up the slack for the mother is going to be there. Boys may have more social/cultural licence when it comes to 'rough and tumble' and 'fighting your corner' which can slide over the line into bullying.
I think the eldest tend to invoke their delegated authority over the younger ones, in most cases, and if that fails fall back on "I'm telling Mom and Dad", not so much as going for bullying. I can see younger (especially middle) kids bullying because they don't have the same quasi-parental status so to make their younger sibs fall into line, they have to bully.
I think I have being an only child to thank for a lot of my personal weirdness. But I think the domestic thing is hardwired; I did most of the chores when I had female roommates, probably more than I do living with my husband. I think what I get while cooking and cleaning is kind of a flow state. Whoever gets their groove on doing chores will probably end up the homemaker in a household. Childcare is just kind of an extension of that, at least so far (I have little kids).
Anecdotal, but this makes complete sense when it comes to my childhood. Younger of 2, both pretty intelligent.
When at a young age my brother discovered e.g. that you can use strategy in games, he found that it let him win every game against me, so he focused on that discovery, and soon even won some games against my parents.
When at a young age I discovered that I could use strategy at games I found out that it does not matter, I never won a game not entirely on chance no matter what I did (because my brother of course by then was way better at strategy). So I stopped playing Risk, or Chess, or any games like that after a while, because what fun is it if you never win?
Sports was similar.
So my brother learned young that if you dedicate yourself to something, you can excel. Tends to produce a strong work ethic.
I learned young that what I do doesn't really change how things turn out.
You may not be surprised that his academic achievements surpass mine...
Wait, we've got to supplement this one, as we have actual data/knowledge here that goes beyond anecdote.
In sports - at least in basketball where it has been most studied - we know that (i) younger siblings do better and (ii) a factor in a talented kid developing into a pro-level talent is them playing a couple of levels up throughout their youth, with kids a couple of years older than them (something younger siblings can do naturally, obviously).
Essentially, when you're talented it's easy to stagnate, to rely on your physical advantages and fail to develop the finer points of your game. This is especially so with guard skills (three point shooting being a classic David vs Goliath strategy) that you don't need to bother with when you can just overwhelm your opponents inside.
Applied more broadly, older siblings crushing younger, inferior competition shouldn't make them great at those activities - there's obviously a lot of sips between the cup and the lip in your brother's story, in going from beating his kid younger sibling at strategy to beating his parents.
Whether younger siblings develop effective David strategies or just keep getting pummeled and lose interest may depend on the activity. But there's at least some documented advantage for long-term high-level skill development for younger siblings who are able to hang with their older siblings and compete
There probably is supporting evidence to that in competitive martial arts. Muhammad Ali had an older sibling who boxed AFAIK. And among fighters I know, in families with known talent, talented young siblings seem to fare better. They have to struggle, but their brothers won't crush them, nobody's crushing them if they have big fighter brothers and they can develop well.
From my experience as a South Asian/East Indian immigrant (not necessarily high-income) is that among my first cousins on both sides, the oldest of the family is always the most 'traditionally successful' in levels of education, type of field, and income. This is regardless of gender or varying family income or significant life events.
Culturally, there's an idea that the oldest needs to make it for the family and the pressure is intense to do really well in school and everything else. I am not American either, so I can't imagine how much more formalized that gauntlet is with US-style admissions, etc. Perhaps there's something similar for Western families but less explicit and less tear-inducing.
in the developmental psych literature, does parental pressure itself do better than parental investment in the form of Advanced Einstein baby toys or reading books? Its hard to disentangle the two, of course both nature and nurture-wise.
Just a gut feeling, parental pressure can backfire real hard.
I often think of this kid I tutored years ago. Son of Korean immigrants, oldest of three boys. He wanted to ace the SAT, but he was under so much pressure to excel and set a good example for his brothers that he’d totally lock up when asked to write anything. He said once the clock started it was like his mind went blank, and he could only come up with 2-3 sentences that felt worthy before time ran out.
I tried breaking a good essay down into small parts and asking him to think of them in order when he got stuck. We used little tricks like diagramming an essay directly on the writing prompt. Then we did a kind of timed writing exposure therapy where I gave him silly fun prompts and 10, then 5, then 2 minutes on a stopwatch to see how much he could put down on paper. It sort of worked; he went from writing almost nothing in 30 minutes to filling a page. I recall he did OK on the SAT if not spectacular.
I think some consideration to the ideas outlined in "Deep Nutrition" a book by Dr. Cate Shanahan which talks a great deal about the findings made by Dr. Weston Price should be included. The idea is that nutrition plays an enormous role in physical health and intelligence. Their assertion is that inadequate birth spacing (less than the 4 years they consider ideal) means that the mother is nutritionally deficient which is then passed on to the child creating less than ideal conditions for proper growth and maturation. I am by no means an expert, but I think this merits discussion.
It's fascinating to see this effect in the data - it's *quite* clear in my own life. I'm the oldest, a lifelong nerd. One of my brothers is two years younger and always rejected academic stuff - not necessarily less smart, just much less interested in it. Then my other brother is several years younger than both of us, and pretty nerdy. Point for point reflective of what we see in this data.
I think nerdiness has more to do with it than intelligence or education. I'm about as smart as my sister, and we're equally well educated, but I have a hard time imagining her enjoying this blog. (I'm the younger one, though.)
A major difference that I don't see in the comments below is that first-borns with reasonably small age gaps are always a bit further along than their siblings. If you're a parent and you want to teach something, it is very likely the first-born who is most able to learn it. If an opportunity comes up and you're trying to figure out which of your children is best positioned to take it, that as well is most likely to be the first-born.
"Given that readers of this blog are highly-educated (about 37% have masters or PhDs) and mostly in STEM (41% programmers of some sort), plausibly birth order affects something about intelligence, education, or STEM orientation"
Well, if I didn't have Imposter Syndrome beforehand, I do now! Should I bask in the reflected radiance from the smart and successful, or ask 'what the hell am I doing here?' 😁
At least I *am* a firstborn so that's legit!
People did a major campaign to bring you back when you were banned, so you must be doing something right.
Damn – that's some juicy gossip. I need to catchup on the recent posts I haven't yet read!
I have always relied on the kindness of strangers 😁
Honestly, though, when I look around at the intelligent (and handsome, talented, and modest of course) company I'm keeping, I go "how the heck did I finagle my way in here?"
Birth order effects - well, I think there is a difference between how the eldest and the rest of the siblings are treated. For the eldest, it's the firstborn child, parents generally are not experienced, and generally put a lot of effort in. This results in both good and bad attention; you do have your parents able to spend a lot of time with you and work with you on everything from going for walks to teaching you to read.
It also means, however, panicking about minor things (every kid gets colds and sniffles and all sorts of illnesses, inexperienced parents worry that this could be something major), and a lot of attention on how you behave, how you do in school, etc. because this reflects on them and their style of parenting - they're as afraid of being judged as bad or neglectful parents as you are of being judged a lazy or ungrateful child.
As you get older, that advantage gap over your younger siblings does remain, but it also means that (1) the more siblings you have, the more relaxed your parents get, so there really are fights over "Mom and Dad never let *me* do that!" (2) you do get responsbility as "you're the older one, you must look after/help your little sibling(s)" (3) when you're very young and attention gets split with new baby/younger siblings, yeah you do get jealous because now you're no longer the sole apple of their eyes.
I don't know about carving out non-competing niches for attention, maybe it is so; from my own experience, being interested in 'intellectual' (for want of a better word) pursuits was how I bonded with my father. My siblings went different paths; my younger sister was more traditionally 'girly' and bonded with my mother; my younger brother was smart but could not wait to leave school and go into work, and my youngest brother (the only one of us with a college education) ended up as a high school science teacher.
So, maybe this is how we all picked different ways to not be in each other's shadow? Who knows?
I think you’re on to something with the father relationship.
Recent posts are their own reward, but this wasn't all that recent. It might even go back to ssc.
Ahh – that would explain it! That does now seem vaguely familiar.
I bet you could be a competent programmer!
(I don't think there's much to 'worry' about in terms of not having a Masters or PhD – I don't have one! School's bullshit! This could be, of course, self-serving ego protection!)
Is it possible that first siblings are more likely to contend with mental disorders, and subscribe to this blog for the psychiatric content?
"This was surprising, because at the time lots of studies had shown there weren’t really birth order effects (that is, firstborn siblings had no major personality differences compared to laterborns)"
What were those studies? Do they seem to have been decent work?
Has anyone checked the data for siblings _raised separately_?
The question that I'm really interested in: where are the younger siblings filling out surveys? Is there another blogger (or vlogger) that has that audience? I'd like to find them.
Someone suggested that it's totally possible that there's no effect of birth order on blog readership, but the effect is entirely of birth order on propensity to fill out surveys.
I would assume if it were firstborns are significantly more likely to fill out surveys at all, that would show up in the decades of voluntary psych research already and we wouldn't have this establishment bias that there isn't birth order effect.
Plus if we could identify even one villainous hive of secondborn survey-fillers that would be pretty good evidence and fun to investigate.
So: anyone here have a younger sibling who filled out a survey on a different blog/vlog but didn't fill out the one here?
This paper supports the social over the biological explanation for birth order effects, using people whose sibling died early to differentiate the two explanations: https://www.science.org/doi/full/10.1126/science.1141493?casa_token=D9rI2H8xO1QAAAAA%3A_a1enql0bllAir1AhNMzaQUmWhg6kdrHG4r44IhYxecA-Rga2uPq51EflwvpTKKRy-aXnhanT7l0Iw
Another reason your "trollish" concern about twin studies doesn't get us out of the problem is that adoption studies tend to find the same results as twin studies re the low effect of shared environment.
> Followup research by Less Wrong user “Bucky” determined that the effect fell off with age gaps; the closer in age you are to your sibling, the stronger an effect birth order has.
Some supporting anecdata: I'm the firstborn in a family of six with three triplet younger brothers who are two years younger than myself. Interestingly, the differences between my three fraternal triplet younger brothers are stronger than those between the three of them and myself, and those differences really do line up with the observations made in this essay by multiple metrics.
If I were to identify a cause, it might stem from my parents consistently treating the elder among us as "more mature" and frequently giving us more responsibilities while doing the opposite with the younger, going as far as actively taking away responsibilities. (Yes, they did this even though my three brothers were pulled out of the C-section mere moments apart.) As we grew, we'd reinforce this dynamic among ourselves, often as justification for why the elder deserved certain privileges or why the younger could neglect certain duties. Without a doubt, this sort of treatment had significant effects on all facets of our psychological development, both cognitive and emotional.
I have noticed that the youngest sibling tends to be the "coolest" - i.e. more popular, social, etc. Possibly because they have an older sibling to teach them, hence the stereotype of the cool kid who knows about sex and alcohol because of his older brother. Others have already mentioned differences in parenting, which could contribute to this as well (parents are more lax with rules as # of kids increases -> younger kid spends more time partying and less time studying). Not sure if this is a real effect but perhaps the birth order effects noted here are not so much about older siblings being smarter or more STEM oriented but their younger siblings being less so.
Older siblings are also older. Maybe their younger siblings just have not yet discovered ACT but they will when they come of age.
This would be true if we're looking at children of parents in a particular age cohort. But in the general population, the number of people who have exactly one younger sibling is exactly the same as the number of people who have exactly one older sibling (with possibly a very slight bias in favor of the number with exactly one older sibling, because of a slight imbalance in cases where one of the two siblings has died).
This is not compatible with there being an inverse relationship between age gap and birth-order effects. And if we're looking at siblings with large enough age gaps for what you're describing to be possible (remember, the average age of readers here is 33), then you would also have the issue of first-borns being too old to get into this like sub-stack blogs.
Good point about the age gap relationship. My theory would predict a direct relationship, or perhaps inverted-U if we suppose that the older siblings may have aged out.
The inverse relationship really does seem to indicate an in-your-big-brother/sister’s-shadow mechanism at work.
I don't know if you account for half-siblings here and whether this is on the maternal or paternal side.
Maybe scenarios with a biological sibling but not a social sibling are disproportionately of type: dad has a child from a previous relationship but doesn't have custody, has second child in a subsequent relationship.
Dude, isn't the simple and obvious explanation that the older sibling develops a leadership role and therefore has to be more serious and intellectually-inclined? As opposed to comedy or sports?
I'm not sure what the biases in this kind of analysis are, but as a control group I'd be happy to see it done on other blog readerships or other self-selected groups.
Two of my children are quite close in age. They are close enough when they were small it was easy for them to forget that there was a significant age gap. So the older one was convinced for years that he was really smart; and the younger one was convinced for years that he was an idiot -- when actually they're about the same. Also yeah, they get the "oh, reading big science book's is something my older brother does" factor too.
One hypothesis I though of was that. In the ancestral environment, there was a need for different types of skills and personalities, but by the time someone was old enough to see for themselves which personality types the tribe is short of, it is too late for the brain to make the necessary adjustments. One way around this is for children, in early childhood development, to look around and see what personality types and skills surround them, and then pick complementary skills. Since most young children spend most of their time with siblings, this would create the effect. This would explain why sex doesn’t seem to matter, and why age gap does— children spend more time with siblings closer in age.
Source: oldest in a family of four, each of my siblings has a personality strong in the thing that the sibling one above them is weakest in.
Scott could see if this is true by, in the next survey, asking people how much time they spent with their family in early development, versus, say, a day care, and then seeing if more time = stronger effect.
I realize that this doesn’t actually explain why oldest children in particular are reading ACX, this part is more of a stretch, but maybe, since we live in a society which values STEM type mental abilities highly, oldest children optimize for this, and younger children optimize for it less to provide complementary skills.
The problem with this is how do older children *know* to optimize for this. Certainly they don’t consciously, but maybe subconsciously they respond to cues. But how can the subconscious tell?
I hope the next survey has questions about the father relationship. Time spent, type of time spent, his interests, stepdad(s) involvement, general “male role model” stuff. Father-child personality match, likelihood of laughing at a “dad joke” etc.
That doesn't align with my experience (doesn't mean it's not true; n = 1 and all that). I'm a bookworm and an introvert because that's what I am by nature, not because I looked around in early childhood and decided, "I know what this place needs - more bookworms and introverts!!!" Then again, I am an only child, so I never had to differentiate myself from my siblings.
I don’t think its a conscious decision. Scott has a book review that explains epigenetic markers “looking around” in early childhood and developing a life strategy accordingly.
“Del Giudice seems to imply that a similar epigenetic mechanism “looks around” at the world during the first few years of life to try to figure out if you’re living in the sort of unpredictable dangerous environment that needs a fast strategy, or the sort of safe, masterable environment that needs a slow strategy. Depending on your genetic predisposition and the observable features of the environment, this mechanism “makes a decision” to “lock” you into a faster or slower strategy, setting your personality traits more toward one side or the other.”
Or maybe its on a more basic level, where the most rewarding tasks in early childhood are those in which you have a comparative advantage, which is at least partially a function of what society has not invested enough in, so you continue to develop your comparative advantage
Source: https://slatestarcodex.com/2018/12/03/book-review-evolutionary-psychopathology/
You got something here, I think. Example: The Karamazov brothers.
The ideas I see are interesting in terms of why older siblings would seem smarter or more interested in STEM... but in general I think it would be useful to ground them back to how exactly they would increase their chance of reading this particular blog. This blog ends up having a STEM stereotype, but actually the content is pretty varied: the biographies of dictators, cost disease, drug discovery and pricing, "Untitled", "You are still crying Wolf", Unsong-adjacent and Fifty Swifties...
Another issue is that maybe older siblings are more interested in filling in surveys? There are older-sibling stereotypes that they have an inflated sense of self-importance; and stereotypes that they have an inflated sense of civic responsibility -- if either were true then that could change it?
I think probably the biggest selection factor on your blog is an attention span? The style of burying the lede deep into the twentieth sub-paragraph (which I'm not knocking -- I enjoy) is the opposite of what pretty much everyone else does -- it is the opposite of clickbait, and means that you normally have to read a few paragraphs in before the hook -- and I have always imagined this is one of the reasons the comment section here is so good. Again, it would make sense to me that older siblings have a longer attention span. If the first child has two parents to entertain them. The second child has two parents and an older sibling to entertain them.
I was wondering about networking effects. I know about this site from word-of-mouth. How do other people generally know about it? Do older siblings have larger networks? What I generally observe in families I know is that older siblings are often closer to the parents' generation than younger siblings, who seem more distant socially somehow -- so in this sense, I guess they have a network boost. I probably get send more links by my parents, aunts and uncles, than a younger sibling of mine would -- maybe I should ask. Again anecdotally, but it seems to me that connections travel up through older siblings more often than down through younger siblings. Maybe it's a seniority thing: it seems cool and interesting to get to know your friends' older siblings -- they're always at the next stage of life; but maybe not so much their younger siblings?
"How do other people generally know about it?"
I was reading the comments on an NYT article about nursing homes, and a commenter posted a link to Scott's Slate Star Codex classic "Who By Very Long Decay." I read it and was very impressed (and horrified), and started diving into the Slate Star Codex archives. When Scott shut down SSC and opened ACX, I moved here.
My immediate thought is that second borns grow up in a complex social situation with peers. That may require them to develop more complex social skills/pay more attention to interpersonal situations. That may skew later career choice away from STEM fields. (More specifically some non stem fields gain attraction while stem stays the same, losing relative attraction)
I'm surprised Scott missed this seminal paper by Raj Chetty from Harvard- https://academic.oup.com/qje/article/126/4/1593/1923939
Even Bryan Caplan concedes that the signal that this paper picks up is sound, and weakens Caplan's hypothesis somewhat.
It says that although parental income, environment at home, etc does not affect future earnings as much, one thing that invariably does affect future earnings and achievement is the quality of kindergarten training. I suspect that it is this effect that is even stronger at younger ages (say the first year of the child's life), which is what Scott is picking up in this survey.
First-born children face more pressure from their parents to do something practical and conventional with their lives.
Meanwhile, the key demographic of readers of this blog is "Frustrated philosophers" -- people who wanted to study philosophy at university but wound up doing computers instead.
Stupid question: How do you control for the effect of older-born siblings *being older*, and thus having had more opportunity to become ACX readers?
Within a given family, older-born siblings are older. But within the general population, I don't see any obvious reason this would be true. We're not sampling families; we're sampling individuals.
If you pick an age (say, 33 years), and ask what percentage of first-borns are currently that age, and then ask what percentage of second-borns are currently that age, why would the answers be different?
Or put another way, the younger siblings who are excluded by being too young (or not yet born) should mirror the older siblings who are excluded by being too old (or already dead).
This is not compatible with birth-order effects being inversely related to age gap between siblings.
It seems to me that ACX doesn't select for intelligence, it selects for a certain kind of intelligence and temperament. Wide interests (I think of that as fannish), a tendency to want to look at things from the outside, and at least some tolerance for liberal/anti-progressive politics.
Do venues which have smart people but differ on the other factors still tend to have a lot of first-borns?
Yes, the thing that most distinguishes the SSC/DSL/ACX commentariat is not that we are so much smarter than everybody else, but that we're ultra-nerdy rationalists and very disproportionately in STEM fields. See also Nobel prize winning physicists, great mathematicians, and maybe (modulo the STEM part) Harvard philosophers. We like to Think, and mostly about Things. If we have to understand *people*, our first instinct is to turn them into Things that we can rationally think about, e.g. collections of statistics.
I'm pretty sure that, and not IQ, is what is being selected for in the observed birth order effect.
SSC/DSL/ACX readership is almost assuredly selecting for intelligence. It's that intelligence is not sufficient to explain what separates this crowd from other intelligence-selected crowds.
Unless you randomly selected people to answer the survey, could there be a confounding factor that first borns tend to answer surveys and such?
Being the 3d of 3, my opinion wasn't worth much at the dinner table. And I don't rate Amazon products or give Yelp reviews. Could being higher up in birth order make a person more likely to answer ? That would tip the balance in their favor if they tend to self select
Signed in to post this comment, thanks for sparing me the hassle!
i'm the youngest with a 9 year gap to the closest sibling, my siblings were basically like extra parents/ guardians.
I think a good comparison for more research would be to compare with only children. To disentangle if it's to do with 'lots of attention when young' vs 'responsible for someone younger than you' vs 'most competent person around your age in your house' among other things.
I second this. Comparing to only-children could hopefully yield some insights. Although it comes with different confounders: Are families with only one child different from other families? E.g. I know some only-children where the parents were quite old and only barely had a child before becoming infertile (they tried to have another).
Having an older sibling close enough in age helps you develop better theory of mind earlier, which makes you grow up less nerdy, and you are less likely to end up becoming a programmer who reads acx
I didn't read all the comments so this was probably raised before but since you are looking for differences in whether someone reads your blog or not one obvious question to ask is how someone came to read the blog. Specifically I read this blog because it was recommended by my older brother. Perhaps there is some asymmetry in recommendations from older to younger siblings and vice versa. (Although that would mean my case goes against the trend.)
(P.S. I did not answer the survey and I am guessing my older brother didn't either.)
Maybe the first borns are just higher variance so they show up more in more selective extreme groups? And maybe that's because the parents pay consistently more attention to the younger one when both have already been born? Or because of something related to the dynamics of having and older / younger brother, like bullying, competition.. or the younger one having to follow the steps of the older one, inheriting the toys that the older one chose and liked, etc.
I don't think it's regression to the mean where people have a second child only when the first one turned out a decent experience, because I think most people that have a child have more than one, right?
OK, my theory from last time around:
It's not IQ or general smartness that is being selected for. What sets this group (and the Nobel-physicist group, and the great-mathematician group, and maybe the Harvard-philosopher group) apart, as I mention in my reply to Nancy Lebovitz, is that we are that ultra-nerdy rationalists, very often STEM nerds in particular, and we like to Think about Things. Which, really, is kind of weird.
A firstborn child, or a social-firstborn or a younger child with a large age gap, spends the first years of its life trying to comprehend a world full of Weird Interesting Things. Some of those things are called "grown-ups", which are technically "people" but from a toddler's POV they're a completely different order of being. They're weird interesting things.
A (not too much) younger child, spends the first years of its life in close company with at least one other *person*, a person not too different from themselves. And if there's a Weird Interesting Thing that they need to understand, maybe the best way to do that is to learn from that other person.
So maybe the firstborn child is more likely to adopt a Thinking About Things outlook on life, rather than the much more common Understanding People outlook. They're not *smarter*, they just use it differently. And really, even most of the firstborns will wind up in the Understanding People group; that's just how people are wired. But if you're selecting three-sigma outliers in Thinking about Things, you're selecting for firstborns.
This seems to me at least as good a fit to the observed data as any other hypothesis, and better than most.
I wouldn't say so. I've met a few and they generally don't seem to have the requisite level of navel-gazingness. If I had to characterize their personality quirks as a group, I'd say (1) they were very persistent, much more so than the average person, or even the average scientist or smart person. They just never give up, never accept 'oh that's how it is / somebody else must know / man was never meant to know.' (2) They were intellectually ruthless, let nothing stand in the way of their ambition (for understanding or achieving some end). If it works, they use it, and jettison any issues of self-consistency, personal pride, or intellectual pedigree much faster than the average smart person.
It can be a little unnerving talking to a person like that. With a lot of smart people, there's a certain amount of mutual masturabation, to put it crudely. A says something that's intelligent and may be insightful, and B says something back that is intelligent and maybe insightful, and that's kind of the essence and purpose of the conversation -- two people who are exchanging ID cards for the Smart Sophisticated Person's Club. "I see that you are very smart? Yes! Also sophisticated! Allow me to demonstrate with this short essay on complex Topic Z...blah blah. Now it's your turn...!" The 21st century equivalent of a Victorian peppering his conversation with quotes from Cicero (in Latin).
But these people can be exceedingly direct. They don't really give a crap if you're smart or not, they just want to know if you know something that might be useful to them. You could be very smart, or you could be a moron who just happens to possess a fact or experience they need -- and being a schmo with an interesting fact or point of view is of *more* interest to them than being a very smart person in possession of exactly nothing they don't already have.
You know how in school you could sometimes score a better grade than you really deserve by seeming smart and interested, basically appealing to the instructor's vanity? Asking clever questions, making insightful but tangential observations? You can't do that, it doesn't work, and for a lot of smart people (including me) that's a bit disconcerting.
Maybe the 2nd and 3rd born get better at so-called "emotional intelligence" because they have to read the feelings of somebody who is much less rational, the older sibling. The older sibling only has to build an internal model of two adults, and most parents strive to be rational, even-tempered, consistent et cetera with their kid. So the oldest kid finds that modeling people as highly rational even-tempered actors works great. The younger one has to build a model much earlier that encompasses impulse, bad temper, inconsistency, irrationality.
Hadn't thought of that aspect, but it fits. The Weird Interesting Thing that is a grownup, interacting with its own children, is a distinct outlier in the field of human behavior and one should never expect any other person to act that way. Siblings are a better model.
Well, the obvious hypothesis that comes to my mind is parental expectations. One thing that is very obvious about parents is how much they chill out between Child #1 and Child #N, for N > 2. For the first (or, worse, only) child, parents' expectations are sky-high.
My kid is going to be some combination of Einstein, Mother Theresa, and Winston Churchill. Since he needs to get a PhD from Stanford by age 25, he needs to graduate from Harvard at 20, which means he needs to go some super-competitive magnet high-school after skipping a grade or two in a superb private elementary school....so damn it we better get cracking at getting him into that enrichment pre-school that has only people with PhDs changing diapers -- he's already 3 years old for god's sake! And stop giving him the regular mashed peas, he needs the choline-vitamin E-probiotic fortified 100% organic mashed peas harvested from the slopes of Vesuvius by the lineal descendants of Aristotle. You want him to turn out ordinary??
Comes child #2 or #3 and it's like hey honey little Billy was eating laundry soap again and he looks unhappy, could you maybe get him some water to wash the taste out?
I remember Gilovich talking about birth order effects in his Behavioral psychology class. He seemed pretty convinced. He liked the explanation that birth order effects stem from having to teach the younger sibling things and that you can see the same effect with only children in the US whose parent's first language is not English. They had to teach their parents.
Could the answer be hiding in plain sight? If you were to start club called the "Older Than 10 Club", wouldn't you expect the membership to be skewed towards older siblings? Either:
a) if both siblings belong to the club, they don't bias the sample
b) if neither sibling belongs to the club, then they don't appear in the data
c) if only one sibling belongs to the club, the older one is more likely to be a member, on account of the fact that there are more people older than 10 than there are people younger than 10.
Maybe this blog is most attractive to people who are older than a certain age, on average, and that accounts for the bias?
"The current scientific consensus is that parental investment in the early years of life doesn’t really increase IQ or educational attainment .. This research challenges those assumptions. If it’s right, the difference in parental attention between an only child and a child with siblings seems to have noticeable effects later in life."
The implication here is that birth order -> IQ -> SSC reading. As a first-born SSC reader I like that theory, but I can think of some more plausible relationships.
Maybe first born have had less socialization and are more likely to enjoy solitary interests?
I can propose one more hypothesis. Firstborn are not more intelligent, they try harder. They grown up being more intelligent than their siblings, their "intelligence" is a part of their self-image. Yeah, now I'm talking about myself. And I'm a pretty severe case of it, up to panic attacks when I didn't manage to hold an image of a very smart person. People really asked me "what happened? why you gone all white?". Yeah, I'm talking now about me, not about all firstborns, but I'm pretty sure that one of two big reasons of my condition is me being firstborn. I was responsible for me and my brother all the time. If my brother fall into a river, than I was asked "how it happened, and why I didn't prevented it". It was like my brother fall victim to my stupidity. It was not literally said, but "you need to be smarter" was one of phrases I heard a lot of time being a kid and in my teens. I rebelled at 14-15 against this responsibility. It is a different story, but note that I rebelled against responsibility, not against me being smarter. It took me 20 more years to start fighting my self-image of an intelligent person.
So, my hypothesis is: firstborns try harder to seem intelligent, they develop the whole strategies how to be (or to seem) more intelligent than others. These strategies include "tactic" reactions to stimuli, allowing to hide their "stupidity" (like if I did not understand what happens, I give others a possibility to ask "what happens" or to say/do something that might help me to understand what happens, and I would try hard to be unnoticed). But it doesn't stop here, firstborns learn to be curious. In an academic sense of the world. To learn what other think about some problem is nice, when you forced to talk about this problem, you could make a reference to a few sources, lay out a few different opinions and then maybe even to verbalize your own thoughts on the topic. Or in other company it is better to "plagiarize": to express some opinions without references.
I told, that I'm a severe case, and I really do not know how bad it goes in minds of other firstborns. But what I'm trying to say, that it is not just "I try harder", it is how I live, it is who am I. I read ACE not because I need more smart thoughts cached, I read because it is fun. But it is fun, because I learned as a kid, that intelligence is my inherent psychological trait, and as a teenager I found ways to match to this trait. It is just conditioning.
I cannot say, I know, how to prove it. I'd try to get an operational definition for my condition, to get a way to measure it by looking at behavior. Then to use it on many people, and to study those who hit high scores on the condition -- let them fill a lot of questionnaires, find all the correlations. Then probably we could find an easy to measure trait which is highly correlated with the condition. And then we might find it in the data gathered here.
Though, there was mentioned psychological research of siblings? Did they tried to give some unsolvable task to siblings, while measuring time they spent on it before giving up? Or to place them in unexpected difficult situations, while measuring "smartness" of their way to deal with it. (I called it "smartness", but really it is not about smartness per se, it is about how they manage to look intelligent people.) It may be tricky to operationalize, but I believe it is possible.
Two things stuck with me:
1) if I understand Becky's comment correctly, the dataset contains more people with zero biological and some social siblings than the other way around, which is surprising to me and may indicate an important selection effect.
2) the whole essay seems to use "being a reader of ACX" as equivalent to "being more intelligent than the average in general", which doesn't sound justified by mere correlation. The fact that ACX readers are more likely to be highly-educated and also firstborns doesn't automatically mean that firstborns are smarter in general.
Most obvious answer I can think of is seniority dynamics. Confidence and success breeds further confidence and success, and the oldest sibling is always at the top of the hierarchy. This fits with the huge drop off we see between Sibling 1 and Sibling 2, and the much smaller effect when going from Sibling 2 onward.
I don't think parents have much to do with it. Kids get most of their social input from peers, not adults, and siblings - especially those close in age - are the most important peers of all.
"One problem with (1) - wouldn’t you expect smaller effects as age gaps get lower?"
Yes, the first year is important, but also consider school/preschool: Age gaps over a certain number of years basically give the second child an experience more like that of a first child, since the first child is out of the house or at least more independent.
I thought it was interesting that the decline of the ottoman empire began within a generation after they switched from primogeniture to agnatic seniority.
As a first born with good general success compared to my siblings, the largest difference today is our openness to experience, and willingness to try to fix a problem. They are just as smart as me usually.
I suspect the openness part could be partially due to me not having much help solving problems when I was little, I had to do it myself, or it wouldn't happen (my parents weren't great at helping) whereas my siblings could always get assistance from an older person rather than do it themselves. Having good initiative on learning and doing pays compounding returns.
I'm doubtful parenting has anything to do with this, likewise infancy, as the effect gradually reduces over 10 years. To me the most plausible explanation is firstborns' requirement to figure out a lot of things on their own. This would inculcate increased amounts of "seeking for the truth"; trying to figure out how the world works. The closer in age a sibling is the easier it is for them to learn by example of the older sibling or to just be directly taught by the elder. A 15 year old would struggle to teach a 9 year old relevant things that the parents couldn't teach just as well.
Supports: This is a social explanation, not biologically dependent. It explains the smooth reversion to the mean rather than dropping off suddenly at some point (as an infancy based explanation might suppose).
Problems: I would expect a small amount of gender disjunction but that seems not to appear in the analysis.
Tests: The effect should decline in more communally raised children, where they have very close relationships with children their age (or one year older).
Disclaimer: I am an eldest with 3 younger siblings (none of who read SSC/ACX).
Great comment! I was thinking of the older teaching the younger too. But instead emphasized the benefit the older child might enjoy by teaching things they learned to the younger sibling. I feel like I get a better understanding of an idea once I’ve taught it to someone else.
Thanks. That's an interesting thought and could be contributing, although in my personal experience it didn't feel like that was significant. I definitely understand things better when I explain them but I seldom tried to teach things via explanation to my siblings.
Here's what I think of the first born. Enneagram 8.
Challenger
Basic Fear: Being controlled or violated by others.
Basic Desire: To determine their own course in life. To protect themselves.
Eights want to stand alone, to have power over their lives, and to achieve their goals. They are extremely driven, resourceful, and propelled towards their vision and purpose. They don’t want to feel indebted to anyone, emotionally vulnerable, or in any way dependent. Autonomy and freedom are vital to their happiness; the only problem is that they may defy being vulnerable so much that they miss out on fulfilling relationships in the process. These types crave a sense of intensity in their lives. Whether they’re race-car driving or starting their own business, they enjoy proving naysayers wrong and testing their abilities and strengths.
In childhood, Eights felt that they had to grow up quickly. Early on they felt that they were in some way responsible for the welfare of their family. There was no time or safe space for vulnerability – they had to be strong. Survival issues were at the forefront of their mind. Being gentle, giving, emotionally open – these typical INFJ characteristics were probably repressed because it didn’t feel safe. In some way they felt there was a risk of rejection, betrayal, or pain if they let their guard down. They developed a tough, independent, hardened demeanor as a way of dealing with their pain.
Eights are in the Gut/Instinct triad of the Enneagram. This means that they have underlying issues with anger. While Nines avoid their anger and Ones repress it, Eights express their anger. They like straight-talk and directness and tend to be assertive themselves. When threatened or controlled they can become explosive and intimidating. They feel very defiant of any institution that tries to control them – and they may make life choices simply to rebel against that institution. Whether it’s dropping out of school because the teachers were too controlling, marrying someone a parent doesn’t like, or driving faster than the speed limit on a bad day.
Unhealthy Eights Can Be: Destructive, Vengeful, High-Tempered, Rejecting, Private, Hardened, Authoritative, Bossy, and/or Confrontational.
Average Eights Can Be: Resourceful, Businesslike, Competitive, Boastful, Willful, Proud, Bad-tempered, Hard-Working, Independent, Visionary, and/or Determined.
Healthy Eights Can Be: Courageous, Heroic, Forgiving, Energetic, Independent, Action-Oriented, Resourceful, Direct, Protective, Generous, Inspiring, Strategic, Decisive, Self-Confident, and/or Authentic.
The results paint a really interesting “secret cultural wisdom” argument for primogeniture
Sincerely believe that its the forced leadership. In group play, (and many other situations) the older sibling has to take to the lead. This means generating play ideas, structuring play, and reinforcing play rules. This would explain why the effect is stronger when the gap is closer, and how it could be social without necessarily being based on parental involvement. I think that this could bias some personalities towards valuing things like intelligence and independent thought without actually being smarter (valuing intelligence might make you more likely to invest in your own, but wouldn't necessarily bump you out of your bracket). You might see some boosts in creativity from early practice - but the overall thing that gets affected is not the underlying skill but the perception of which skills are desirable. That would mean that your strongest sibling-order-effects would be in preferences - characters you relate too, ideas that draw you in, or blogs you read.
Father of two kids here, so my sample size is 1. However, I suspect that the cause is "bossiness". In my family, the younger sibling is the bookworm; she loves to read, and is by far the more STEM inclined. But the elder sibling absolutely loves to "mother" her, and always wants to be in charge of whatever games they play, even though the age difference is only 1.5 years. As parents, we have to constantly work to make sure that the younger sibling has a say in things. I would hypothesize that 10+ years of unintentional "leadership training", or conversely, "follower training", might make a significant difference.
Maybe older siblings are poorly socialized due to having no older siblings, thus more likely to be "on the autistic spectrum", thus more likely to subscribe to AC10.
If my first kid is smart I am more likely to have another one. Add some random distribution of intelligence between kids and regression to the mean and we have an explanation.
Another possible mechanism, which is biological, but not genetic, is the potential effect of early illness. Just anecdotally, my first child wasn't sick for the first year of their life due to lack of exposure to other kids, but I fully expect my second to be sick much earlier due to picking up things from the older one. I'd expect this to attenuate over time as the first is more able fight off infections before they spread to others.
If this is true, I'd expect this effect to vary based on when/whether childcare like daycare is used (and what type). Also does this vary over time? Were there birth order effects in the early 1900s, for example? How do they vary across countries?
One (anecdotal, unscientific) observation I have made is that boys with older brothers (this one is sex specific) tend to have more tenacity than those without. I attibute this to the type of rough play the boys tend to get into (much to their mothers' chargrim) wrestling, stick fighting, etc. The younger brother will almost always lose such games and yet is expected to play on anyway to grow stronger and hope for the sweet moments when he can catch the older brother off guard.
I would love it if someone could suggest a way to test this theory or even better actually test it.(The hard part I believe it's coming up with a suitable metric for "tenacity", I am highly skeptical of anything involving self reports)