I trust my own observations and my conclusion is that heritability is very strong. This is not a view that was imparted on me, quite the opposite. Growing up in a western country I was led to believe we are all blank slates, and I truly believed it. Once I started spending more time around the opposite sex some doubts started to emerge. Once I became a parent it became very apparent that this ideology had no basis in reality. Kids come with a personality, batteries included, and it's very easy to point out even individual behaviors that originate with either parent. Boys and girls are also very different on average. It's insane that we have somehow convinced ourselves that this is not the case, and I will surely be attacked by just pointing this out. I don't need twin studies to understand this basic fact, a fact that's been apparent to everyone throughout history, except for the past ~40 years in the west.
My father was told all his life that he had the same character than his mother, and until I was 10, I was told I showed the same character as my grandfather (I still have his walking cadence and posture).
Why would you decide to hold a position strongly based on a minuscule and extremely biased sample set and reject even considering data and studies outside of your immediate experience?
Unless you’re afraid your conclusion might be challenged? Wouldn’t it be interesting either way? Either to find out that your children are typical or to find out that you and they are special in some way?
I understand many people are not interested in or curious about science, but don’t understand people who are both disinterested but also strongly hold particular positions on scientific questions.
It's also just common sense. Everyone agrees that traits like height is heritable, but somehow whatever goes on inside the brain is not? The null hypothesis here is that it is heritable, and I see no proof whatsoever against that hypothesis. My personal experience raising my own kids and observing countless others confirms common sense. Your own child is not one data point, it's a million small data points, things you notice in what they're like as a baby, and how they develop over time. Only someone without kids would boil this down to a "single data point". I also deny that I have do anything to prove heritability, how about you prove the opposite? It's a conclusion that is so obvious to the impartial mind that to be confused about it is a sign of extreme ideological indoctrination. To deny heritability of personality and intelligence is to deny evolution itself.
I agree. A child is a million small datapoints. My son established a strong personality early on that defied our attempts to modify it. Meanwhile he was raised in a relaxed environment that certainly provided no environmental explanation for his fixations.
I was raised with five siblings, yet only I got into fights at school, and made my mother cry on a regular basis. Each of my sibs is similar and each of us is strikingly different, too.
No-one is denying heritability here. The only question is where the heritability figure lies, and how reliable are the estimates that have been put forward in the past.
I don't see how anyone's "personal experience" could be a valid methodology for deciding whether the heritability of IQ is 30% or 80%.
As for the "extreme ideological indoctrination" slander, it'd be great if you could just withdraw it.
Centuries of success with empirical based science is a direct rejection of the approach of trusting "just common sense".
> Only someone without kids would boil this down to a "single data point".
Why are you personalizing this? I have a family and have observed children grow from emergence from the womb and I grew in a much larger family. I'm not sure what the relevance is to the points being discussed. This seems like argument by anecdotal fallacy.
> I also deny that I have do anything to prove heritability, how about you prove the opposite?
I didn't ask you to prove anything. I asked you why you have no interest in looking at a scientific question beyond "I trust my own observations and my conclusion"?
And this question seemingly misses the point - it not a binary question about whether traits are inherited or not but about the degree of the role of inheritance. The author of the piece emphasizes this point extensively.
The salient point of the too-long article was about flaws in a seminal paper on this subject where the author Bouchard presented carefully collected data for identical twins - showing remarkably low variance suggesting a high degree of inheritance. But he hid the data he had collected for non-identical twins, which would have provided us with a basis for judging the significance of the findings regarding identical twins.
> It's a conclusion that is so obvious to the impartial mind that to be confused about it is a sign of extreme ideological indoctrination.
Can we just discuss the science and statistics here?
It’s just Bayesian thinking. Too much open mindedness to scientific papers can have you frequently changing your beliefs based on some recent scientific paper that came out, or even worse based on a recent college graduate journalist’s summary of a recent scientific paper from some random university..
As opposed to holding on to a belief that has been reinforced via personal experience countless times until very strong evidence proves otherwise. You end up with a set of beliefs that have a much higher chance of being true this way.
I don't understand why you are challenging me here?
Isn't your question exactly that addressed by the (admittedly too long) article? That the graph Paul Graham presented proving the dominance of inheritance wasn't based on any science or data?
The article only asks the question of scientists have data to conclude that IQ is inherited. The author is only saying that there are so many problems with the little data we have, that he cannot rule out correlation without causation.
> The question never was about whether or not genetic differences contribute to the spread of intellectual talent—they obviously do. The question always was about the “interesting place” Paul Graham talked about, the meaningful space between genetic potential and actual achievement, and whether or not it really existed. And, at 30% or 50%, this place surely exists.
That heritability doesn't cover all genetic factors. E.g. out of 100% of IQ variation 50% might be inherited, but that doesn't say that the rest is nurture, right? It can still have a huge factor of genetic lottery. E.g. isn't heritability the mean of the genetic effects, but there's also the rest of the distribution (std. dev)?
Also count me in for disallowing childless people in many of societies political leadership positions. A position I would have found ludicrous 10 years ago. ;)
It’s just not possible to understand the best way forward for the species if you haven’t procreated.
This seems like a bad criteria for many reasons. What about people who delay procreation till their late 30s or 40s? Or people whose children have died?
Then there's a category of people who resent their children and younger generations generally.And another category of childless idealists who feel protective of humankind and the planet as a whole. Would you approve the resentful and deny the idealists?
That seems backwards. People with kids tend to prefer the way forward that is best for their kids even if it makes things worse for many more other people (adults and kids).
People in general don't like being told they're wrong. This means that arguments that challenge status quo get suppressed. Science isn't magically immune to this just because you add a label "it's scientifically proven, bro!". Therefore, a lot of research on controversial topics can be safely discarded simply because people doing the research have lots of reasons to be biased. This is especially relevant in social sciences, because it's a bottomless pit of controversial topics, and has almost zero possibilities of repeating an experiment. Sure, we have 50 years of research proving that children are blank states, but it's important to remember that eugenics were deeply rooted in science too. It's just that different societal attitudes expected scientists to come up with different scientific results, so they did. Think of a society-wide version of corporate-sponsored research centers that are expected to massage the results until they match the desired outcome.
Another thing is that sometimes it might be beneficial to believe something that isn't true. If you knew for a fact that tomorrow 99% of population will suffer extremely painful death then from the point of view of an individual the correct move would be to commit painless suicide, but the survival of humanity relies on everyone believing they'll be all fine. This is obviously a caricatural example, but there are lots of such lies that keep the society going, and "we're all equal" is just one of them.
Personally, I find it extremely difficult to believe that we'd be born equal, because evolution works only if some individuals are better than others, and I strongly believe that evolution is a thing.
It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value. To do otherwise requires living one’s life in cognitive dissonance; how could they be worthy of such riches while others struggle to just pay the bills? Surely success and intelligence is just an inborn thing, and thus inevitable and unchangeable. There’s nothing they can do, and it was always going to end up that way. Inevitability erases any feelings or guilt or shame.
Ironically IQ is also popular amongst people in a very different situation, that is, people that aren’t actually successful “in the real world” but score highly on aptitude tests. Their high scores serve as an identity pedestal to look down upon others and set themselves apart from the masses. This seems to be the primary demographic of IQ-requirement organizations.
Now of course there are scientific studies on this topic, but let’s not pretend like this is a cultural meme because writers like Cremieux are just tirelessly searching for the truth, no matter what ideological consequences that may have. They quite obviously have a viewpoint first and then work backwards from there to justify it.
As a meta comment: the whole obsession with IQ as a kind of unchanging permanent quality seems very much out of tune with how biological systems actually work, and is kind of a remnant of a Platonic worldview. That is, it’s not dynamic/process/system oriented in the way that nature actually works, but instead is in search of eternal qualities á la Plato.
Smart people tend to have gifted children, this is, unfortunately, factual.
Being smart is a poor proxy for success, you have to have access to the right knowledge and resources at the right time, and often the “smart” move is short term.
It could be argued (and often is), that the reason intelligence is strongly predicted based on heritage (though of course: not guaranteed) is due to your parents interactions with you as a child.
like many things, I’m not qualified to answer.
Sufficed to say that some of the smartest people I personally know are more limited in their success than some of the confident yet much less intelligent people I know: who seem to be, in general, much more successful.
The correlation between success and intelligence is as you say highly circumstantial. There are few areas of endeavor where intellectual prowess is the determining factor—normally persistence, luck, and resources are more determinant.
That said, the experiences of my youth in animal husbandry make me a strong believer in genetic determinism.
It is empirically practical to use breeding alone to predict cognitive abilities, behaviors, tendencies, and elicitable capabilities in animals, given identical rearing environments. Right down to nervous ticks, inherent fears, very specific nuisance behaviors, as well as predictable desirable behaviors, dispositions, and fascinations. Even preference for certain types and even colors (shades?) of toys over others. The fine grained nature of determinism in behavioral tendencies is remarkable.
There is so much overlap of structure and function within mammals that it is extraordinary to claim that apes are somehow exceptional by categorically fundamental properties rather than degree.
Great apes are much more adaptable and capable than most animals, and environment probably plays a much greater role in our development because of the power of our faculty for learning, but that does nothing to negate the underlying heritability of extremely fine grained cognitive traits.
Animals are in no way blank slates when they are born. Genetic or in-utero programming plays a huge role in cognitive processes, and cognitive capacity is a direct dependent of physical structure.
One does not predict the other necessarily, but there is still a difference between a partially full mug and an overflowing shot glass, even if they hold the same volume in practice.
We are born with unequal capacities in both physical and cognitive realms. It is an uncomfortable truth. We do ourselves a disservice when we try to pretend inconvenient things are not so just so we don’t have to face uncomfortable choices.
If true, this doesn't say anything about heredity though. It could just as well be all about environment and smart people carrying the same kind of environment on.
> It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value.
I agree that that could be a motivation. But I would also say that having a motivation for a given result doesn't preclude that result. That is generally true in science.
I'm not an expert. But there seems to be fairly overwhelming evidence that some significant amount of intelligence is heritable. That IQ is a reasonably good measure (or proxy) for intelligence. And that IQ correlates well with a lot of other things like educational attainment and income.
That doesn't mean that your genes determine your future. But it does suggest that some people are "born" in a better position than others -- aside from their socio-economic status.
This shouldn't be controversial. Height is well-known to be heritable. Being tall gives you a better shot at making the NBA. The same is true for many other things.
> This shouldn't be controversial. Height is well-known to be heritable.
I don't understand why so many commenters here are arguing against a straw man. The article author does not and never did believe in the "blank slate" theory. The author has a "centrist" view that genes matter but are not the only determining factor.
I was responding to the previous comment, not so much the article.
> The author has a "centrist" view that genes matter but are not the only determining factor.
Nobody thinks genes are the only determining factor (that's a straw man on the other side :)
Most people agree it is somewhere on a continuum. Some people think it leans more one way; others the other way. Some people want it to lean more one way; others want it to lean more the other.
> It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value. To do otherwise requires living one’s life in cognitive dissonance; how could they be worthy of such riches while others struggle to just pay the bills?
It doesn't require any such thing. It doesn't take a super genius to understand the roles of chance and circumstance have on one's lot in life.
I agree it doesn’t take a super genius to understand that, but it does require something like deep emotional intelligence and ethical sense for someone immensely successful to truly accept that chance and circumstance may be largely responsible for their success.
There aren’t a lot of billionaires out there acting in a way that shows this. At best, they give the idea some lip service.
Complex question that depends on one’s ethical views, but I’d say not pushing the idea that inequality is good, or retweeting people that are obviously ideological making heritability claims, is a good start.
From there, the sky is the limit. Directly helping underserved communities access the same networks/resources is another. A handful of billionaires have also donated their entire wealth, but the laudability of that depends on your ethical stance of course.
I don't see how lack of either of the suggested options is any kind of indication that the person doesn't accept that success has a factor of chance.
I doubt there's even a claim that this is right ethically or that you are not displaying a hipocrisy here. How far is your own wealth from the worldwide median?
I really don’t understand what point you’re trying to make.
That someone could be a billionaire, spend their time writing essays about how inequality is good, retweet and give attention to people insisting that intelligence and success are mostly inheritable – and yet also deeply understand that their success is largely dependent on chance? Uh, I guess such a person could exist, but it seems like you’re just nitpicking here.
And of course there is an obvious ethical claim here: that people who benefit from a system and become wealthy should feel some sort of ethical obligation to contribute to or improve access to that system. Or at least not actively try to deny that such a system helped them. This is a complicated topic which is why I said “depending on one’s ethical views.”
No idea what my personal situation has to do with this, but I assure you, I’m not a billionaire, nor am I wealthy, unless merely being born in a Western country implies that one is wealthy (a nonsensical claim.)
> the idea that metrics like IQ point to some sort of “universal independent” metric of value
What’s particularly annoying is that this can so easily be proven false. No amount of heritable IQ points are gonna help if you’re born to a starving family escaping genocide in Sudan.
But also, “IQ” has been a useful characteristic for a few decades to maybe a few centuries at most. For most of human existence, pure physical strength was likely much more useful than the ability to do abstract thinking.
So even if we accept all these easily disproven ideas, it’s still clearly evident that the fact that they’re in a position to benefit from these supposedly heritable traits is only because they happen to be extremely fortunate to be born in a time and place where these traits are actually valuable.
Several 9s of humans that ever existed would have found an Einstein level of genius worthless
There's also the problem that many "IQ" tests are heavily biased toward a Western, Anglophone education.
Being able to correctly say, for instance, which of four options a "façade" is most like has nothing to do with inherent intelligence; it has to do with whether you were taught the meaning of the word "façade", and the four (often somewhat uncommon) words presented as the choices. The same is true for any of the questions that are, even in part, testing your vocabulary.
Presenting such a test to two people, one of whom was educated at a private school in New York City, and came from a family that highly valued reading and education, and the other at a public school in rural upstate NY, and came from a family that thought it was "too woke" for boys to read books, it is painfully obvious which one will do better, regardless of any genetic factors.
> It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value. To do otherwise requires living one’s life in cognitive dissonance; how could they be worthy of such riches while others struggle to just pay the bills? Surely success and intelligence is just an inborn thing, and thus inevitable and unchangeable. There’s nothing they can do, and it was always going to end up that way. Inevitability erases any feelings or guilt or shame.
I've never understood the idea that winning the genetic lottery somehow makes a person more "deserving" or "worthy" than another. To me, the whole idea of "meritocracy" is a moral abomination.
> It seems natural that those that do valuable things get rewarded a lot.
I'm not fond of the term "rewarded." I understand how prices are determined by supply and demand in economics. Obviously in the labor market, some skill that is in high demand and/or short supply will bring a high price. However, economics are largely amoral. The economic system is not an ethical system to reward the worthy and punish the unworthy, just a method of distributing resources.
There's both an uncontroversial and a controversial interpretation of "meritocracy." Uncontroversially, those who are best qualified for a job should do that job, especially for life-and-death jobs like in medicine. This is how the argument usually starts, with the uncontroversial interpretation, but then it slyly shifts to the controverisal interpretation, that certain people "deserve" more money than others, often a lot more money, due to their qualifications. And while we may want economic incentives for the most qualified people to persue certain jobs, overall it doesn't appear to me that the economic incentives align with societal benefit. For example, we massively reward professional athletes and entertainers much more than doctors and nurses.
Ultimately, the controversial notion of meritocracy is used to justify enormous disparities of wealth, where a few people have so much money that they can buy politicians and elections, whereas others are so poor that they have trouble affording the basics like food, shelter, and medical care. And supposedly that's all based on "merit", which I think is crap.
When I was an undergrad (or maybe it was grad - it was a long time ago) we learned about the Minnesota twins study that attempted to find the strength of genetics in personality. The study developed new statistical techniques to measure this and can to the conclusion that genetics is very strong.
But now you hear nothing about this study. I'm not sure if it's because the results are tainted by eugenics, or if the techniques they developed were wrong...
I started the article but couldn't get past the conceit and name-dropping in the first couple of paragraphs. I just went back and tried to skim through it and gave up again after a couple of more paragraphs.
What you call name-dropping is justified by the need to clarify the stakes and be transparent about where the criticism is coming from.
If the article is too long for you & you're already familiar with the notion of heritability, you can go directly to the "The Dog Eat My Control Group" section near the end.
You can see this type of thinking in the absolute certainty that the YC interview process finds every billion dollar company that apply. I’m unconvinced and think a lot of the people who joined those early batches and made so many great companies were changed by their environment not by being filtered for credentials or genetic gifts.
For full clarity: I didn't flag your comment (at least, not intentionally, as I never even thought about doing that)
Now the substance:
"The alleged “suppressed control group” does not turn the result into “no heritability”."
=> Of course not, did anyone claim there was no heritability? But
1/ It's not "alleged", it's printed black on white in the paper.
2/ There is no excuse for suppressing control group data (it's like suppressing the placebo arm of a drug study).
3/ It does turn the result into "junk", and it does establish a definite case of scientific malpractice among people arguing that IQ heritability is 0.70.
As for later analyses, they weren't the topic of my post, but that doesn't mean they're casher.
As for this snide comment that you posted behind your flagged comment:
"I don't care if you find it fair. If you can't accept that genetics determines the entire organism (stress: entire) and does not stop at the neck, then you'd perceive my later criticisms as much worse than - gasp! oh great heavens! my pearls! - unfair. It is a bitter pill to swallow that some people were simply born with better hardware than yourself, one you are obviously railing against. Now, rush on and down vote this comment as well to lighten the burden of your cognitive dissonance. I'm also finding it difficult to reconcile your use of the flag/report on the parent comment versus the rules dictating and describing what is disallowed content. Disagreement is not against the rules. Perceived "fairness" is not in the rules."
Sorry to inform you that you don't understand the meaning of the verb "determine", as "genetics determines the entire organism" is scientifically wrong for obvious reasons: "influences", yes; "encodes proteins for", yes; but "determines", no.
And, no, I'm not railing against anyone's hardware as I'm pretty satisfied with mine.
In contemporary human populations living in typical modern environments, a large share (roughly half or more in adulthood) of the differences in IQ between individuals is associated with genetic differences.
The evidence is overwhelming in that direction:
Twin & family designs: h² ~0.4–0.8, often ~0.7–0.8 in adult samples like MISTRA.
Adoption: people resemble their biological relatives more than their adoptive relatives in IQ, despite strong environmental differences.
Molecular genetics: polygenic scores and GCTA show real, replicable genetic signal for intelligence.
What it does not mean is that:
1. IQ is fixed at birth in a way that cannot be influenced by environment.
2. IQ differences justify any sort of discrimination or moral ranking.
Those two points are where people tend to clutch their pearls and panic. Just because we have noticed an uncomfortable truth does not mean that it is valid to use it in a discriminatory manner; the issue becomes that people will inevitably do so, thus those "in power" cripple the theory in the crib so as to avoid the fearful and uncomfortable implications.
This literally doesn't say anything. It's a lot of words, but you've managed to reproduce the exact position the author of the article has. For those wondering what the trick was here: this comment forwards the 40-80% h2 numbers from twin studies, then says "molecular genetics show real, replicable genetic signal for intelligence", rather than showing the 10-30% h2 numbers those studies generate.
It's practically nobody's position that there's no linkage between genetics and intelligence (that would be weird indeed), but it's important for this comment for you to believe that's the counterargument --- otherwise the comment doesn't make sense.
Another issue is, what is it that you're trying to use it for?
If you're arguing against a eugenicist then it's not just about the percentage, in that case you have to distinguish between genetic and heritable. Suppose that there are some set of four genes that, in just the right combination, are worth 5 IQ points. That's, by definition, genetic, but it won't have a strong correlation with heritability because every kid has four chances to get the combination wrong. Or, if the combination does something bad, four chances to get it right even if their parents didn't. So past performance is no guarantee of future results.
By contrast, if you're trying to decide whether to allocate more resources to kids who already show promise, you care about the individual's natural potential rather than the statistical probability that it will be similar to their parents, so it doesn't matter what was more likely, it matters what actually happened. And by the point you're performing the evaluation, you can't go back in time and change things like the prenatal environment for someone who is already born, so in that context those things belong in the "nature" column and "nurture" only gets the things you could still affect.
Please look at the examples in the article and consider re-calibrating your numbers here. The lower range of heritability means that it is mostly noise.
Which exact passage of my piece triggered this bizarre interpretation? What made you jump from "someone criticizes a 1990 paper in Science for withholding critical control group data" to "this person is subject to magical thinking"?
As it happens, I often run into trouble due to my conceptualist views on the foundations of mathematics (that is, I'm a hardcore physicalist & anti-Platonist cognitivist, which is quite rare among mathematicians), so I find your criticism particularly unfair.
I don't care if you find it fair. If you can't accept that genetics determines the entire organism (stress: entire) and does not stop at the neck, then you'd perceive my later criticisms as much worse than - gasp! oh great heavens! my pearls! - unfair. It is a bitter pill to swallow that some people were simply born with better hardware than yourself, one you are obviously railing against.
Now, rush on and down vote this comment as well to lighten the burden of your cognitive dissonance.
I'm also finding it difficult to reconcile your use of the flag/report on the parent comment versus the rules dictating and describing what is disallowed content. Disagreement is not against the rules. Perceived "fairness" is not in the rules.
Not a word of this responds to the article itself; it's just a series of subjective judgements you've made about the author and have decided to argue about instead. Always the hallmark of a strong position!
I think it's pretty funny that no matter how straightforward the methodological critiques of 90s-vintage twin studies are, they always elicit responses as if the critiques were metaphysical, rather than (for instance) deliberately excluding the dizygotic twin control group from MISTRA because it revealed the studies findings were just noise.
The truth is, for these kinds of studies, the whole enterprise might as well be metaphysical; people saying these kinds of things have formed a religious conviction about the heritability of behavioral traits, and their real objection is that science continues to be done on the topic at all. Ironic, given the frequency with which they complain that this science is suppressed.
(I too have a near-religious conviction about this subject, though in a different direction; I do not, however, pretend that conviction is itself a methodological critique!)
I, and clearly many others based directly on your comment assertion, clearly disagree.
Whether or not you like MISTRA, “they left out the non-identical twins” is a side issue, and the broader evidence that IQ is substantially heritable is extremely strong.
Even if DZA were excluded, MZA alone provides a solid heritability estimate. The DZA sample was small and noisy, and MISTRA uses other twin and family data. Plus, meta-analyses confirm high IQ heritability, typically 0.5-0.8; Later structural-equation models applied to the full MISTRA cognitive dataset (MZA + DZA) estimated the heritability of general intelligence around 0.77, essentially the same ballpark as the original simple estimate.
laplab.ucsd.edu. Intelligence is highly heritable, potentially reaching 80% in adulthood, supported by further studies like the Haworth et al. meta-analysis, showing age-related increases in heritability.
Strong evidence for polygenic and SNP heritability is shown from Plomin & von Stumm's 2018 research, showing how polygenic scores predict general intelligence.
Adoption studies further support the genetic influence, as adoptive siblings show weaker correlations compared to biological ones.
Environment is certainly NOT outweighed entirely or beyond merit, but evidence clearly shows the "uncomfortable" result having strong support despite desperate attempts to debunk.
In short; the op's story only works if including the DZA data actually drags the heritability estimate down into trivial territory. It does not.
Later analyses of the MISTRA sample that explicitly include both MZA and DZA twins and use full structural-equation models estimate heritability of general intelligence (g) at about 0.77 in adults.
https://laplab.ucsd.edu/articles2/Lee2010.pdf
That is higher, if anything, than the original approximate 0.70. In other words:
The alleged “suppressed control group” does not turn the result into “no heritability”.
The more sophisticated models using that very same DZA data still say “IQ differences in this adult sample are heavily genetic.”
You just don't like this data, and don't want to accept it, because of the implications.
I think you may have mistook me for asking for a gish gallop of intelligence arguments, rather than simply pointing out that you ignored the substantance of the article's methodological critique. Which: the comment you wrote upthread is right there for everybody to read.
In my mind, the bigger issue with twin studies trying to show that (say) IQ is highly genetic is that humans do not reproduce by cloning. And regression toward the mean is very much a thing for heritable traits.
In other words - Junior should not be presumed to be smarter, fitter, more deserving, or destined for success, just because his parents did well. No matter how attractive that conclusion might sound, to people who consider themselves to be the "better" sort.
That doesn't sound like a problem with twin studies exploring the degree to which IQ is genetic, that sounds like a problem with people treating aggregate tendencies and associations as a basis for individual discrimination.
The problem is most people's zealous desire to read socially self-serving conclusions into any data they can find on such subjects. And when they really like the Q.E.D. punchline, humans have very low standards for the "logic" used to reach it.
iq is "polygenetic" with the consensus estimates at 50-80% based on genes
success has components of luck as in "right place, right time" for someone with the right qualities and connections, and many of the very successful are quick to admit this
I am a 3rd generation machinist along the paternal line, and although the machines I operate are in expensive labs, those my father and grandfather operated were probably just as challenging. Engineering also seems to often run in the family. How much is nature and nuture? "It varies" is a safe response
Whoah, no, there is definitely not a consensus for 50-80%, and most of what's being published now refutes the 80% end of that range --- the 80% estimates come from underpowered studies like MISTRA that improperly assumed independent environments for twins reared apart.
We have essentially no mechanistic understanding of gene/intelligence interactions. Rather, we have cohorts of people tagged with traits (educational achievement, tested IQ, height, etc), all sequenced, and then we can run correlation surveys across all their genomes to identify correlations between alleles and traits. When you do that, you get 10-30% heritability numbers; the gap between that and the range for MZ/DZ twin studies (the 50-80% you often see) is "the missing heritability problem".
"That is, once you include the rare variants, the amount of genetic variation that “should” exist but doesn’t shrinks to only 12%. Plausibly an even bigger study, investigating even rarer variants, could shrink the gap further, all the way to zero."
Of course, even then heritability will not be 100%.
I trust my own observations and my conclusion is that heritability is very strong. This is not a view that was imparted on me, quite the opposite. Growing up in a western country I was led to believe we are all blank slates, and I truly believed it. Once I started spending more time around the opposite sex some doubts started to emerge. Once I became a parent it became very apparent that this ideology had no basis in reality. Kids come with a personality, batteries included, and it's very easy to point out even individual behaviors that originate with either parent. Boys and girls are also very different on average. It's insane that we have somehow convinced ourselves that this is not the case, and I will surely be attacked by just pointing this out. I don't need twin studies to understand this basic fact, a fact that's been apparent to everyone throughout history, except for the past ~40 years in the west.
My father was told all his life that he had the same character than his mother, and until I was 10, I was told I showed the same character as my grandfather (I still have his walking cadence and posture).
My father is adopted.
> I trust my own observations and my conclusion
Why would you decide to hold a position strongly based on a minuscule and extremely biased sample set and reject even considering data and studies outside of your immediate experience?
Unless you’re afraid your conclusion might be challenged? Wouldn’t it be interesting either way? Either to find out that your children are typical or to find out that you and they are special in some way?
I understand many people are not interested in or curious about science, but don’t understand people who are both disinterested but also strongly hold particular positions on scientific questions.
It's also just common sense. Everyone agrees that traits like height is heritable, but somehow whatever goes on inside the brain is not? The null hypothesis here is that it is heritable, and I see no proof whatsoever against that hypothesis. My personal experience raising my own kids and observing countless others confirms common sense. Your own child is not one data point, it's a million small data points, things you notice in what they're like as a baby, and how they develop over time. Only someone without kids would boil this down to a "single data point". I also deny that I have do anything to prove heritability, how about you prove the opposite? It's a conclusion that is so obvious to the impartial mind that to be confused about it is a sign of extreme ideological indoctrination. To deny heritability of personality and intelligence is to deny evolution itself.
I agree. A child is a million small datapoints. My son established a strong personality early on that defied our attempts to modify it. Meanwhile he was raised in a relaxed environment that certainly provided no environmental explanation for his fixations.
I was raised with five siblings, yet only I got into fights at school, and made my mother cry on a regular basis. Each of my sibs is similar and each of us is strikingly different, too.
No-one is denying heritability here. The only question is where the heritability figure lies, and how reliable are the estimates that have been put forward in the past. I don't see how anyone's "personal experience" could be a valid methodology for deciding whether the heritability of IQ is 30% or 80%. As for the "extreme ideological indoctrination" slander, it'd be great if you could just withdraw it.
> It's also just common sense.
Centuries of success with empirical based science is a direct rejection of the approach of trusting "just common sense".
> Only someone without kids would boil this down to a "single data point".
Why are you personalizing this? I have a family and have observed children grow from emergence from the womb and I grew in a much larger family. I'm not sure what the relevance is to the points being discussed. This seems like argument by anecdotal fallacy.
> I also deny that I have do anything to prove heritability, how about you prove the opposite?
I didn't ask you to prove anything. I asked you why you have no interest in looking at a scientific question beyond "I trust my own observations and my conclusion"?
And this question seemingly misses the point - it not a binary question about whether traits are inherited or not but about the degree of the role of inheritance. The author of the piece emphasizes this point extensively.
The salient point of the too-long article was about flaws in a seminal paper on this subject where the author Bouchard presented carefully collected data for identical twins - showing remarkably low variance suggesting a high degree of inheritance. But he hid the data he had collected for non-identical twins, which would have provided us with a basis for judging the significance of the findings regarding identical twins.
> It's a conclusion that is so obvious to the impartial mind that to be confused about it is a sign of extreme ideological indoctrination.
Can we just discuss the science and statistics here?
It’s just Bayesian thinking. Too much open mindedness to scientific papers can have you frequently changing your beliefs based on some recent scientific paper that came out, or even worse based on a recent college graduate journalist’s summary of a recent scientific paper from some random university..
As opposed to holding on to a belief that has been reinforced via personal experience countless times until very strong evidence proves otherwise. You end up with a set of beliefs that have a much higher chance of being true this way.
What studies ? What data ? David Bessis basically says that there are so few twins reared apart that scientists can't make definitive conclusions.
I don't understand why you are challenging me here?
Isn't your question exactly that addressed by the (admittedly too long) article? That the graph Paul Graham presented proving the dominance of inheritance wasn't based on any science or data?
The article only asks the question of scientists have data to conclude that IQ is inherited. The author is only saying that there are so many problems with the little data we have, that he cannot rule out correlation without causation.
> The question never was about whether or not genetic differences contribute to the spread of intellectual talent—they obviously do. The question always was about the “interesting place” Paul Graham talked about, the meaningful space between genetic potential and actual achievement, and whether or not it really existed. And, at 30% or 50%, this place surely exists.
The author of this piece totally ignored that heritability is only part of the genetic lottery.
What do you mean?
That heritability doesn't cover all genetic factors. E.g. out of 100% of IQ variation 50% might be inherited, but that doesn't say that the rest is nurture, right? It can still have a huge factor of genetic lottery. E.g. isn't heritability the mean of the genetic effects, but there's also the rest of the distribution (std. dev)?
In the exact same boat here.
Also count me in for disallowing childless people in many of societies political leadership positions. A position I would have found ludicrous 10 years ago. ;)
It’s just not possible to understand the best way forward for the species if you haven’t procreated.
This seems like a bad criteria for many reasons. What about people who delay procreation till their late 30s or 40s? Or people whose children have died?
Then there's a category of people who resent their children and younger generations generally.And another category of childless idealists who feel protective of humankind and the planet as a whole. Would you approve the resentful and deny the idealists?
The idea seems pretty flawed and unjust...
That seems backwards. People with kids tend to prefer the way forward that is best for their kids even if it makes things worse for many more other people (adults and kids).
Best for their kids when they’re at a particular age range even.
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People in general don't like being told they're wrong. This means that arguments that challenge status quo get suppressed. Science isn't magically immune to this just because you add a label "it's scientifically proven, bro!". Therefore, a lot of research on controversial topics can be safely discarded simply because people doing the research have lots of reasons to be biased. This is especially relevant in social sciences, because it's a bottomless pit of controversial topics, and has almost zero possibilities of repeating an experiment. Sure, we have 50 years of research proving that children are blank states, but it's important to remember that eugenics were deeply rooted in science too. It's just that different societal attitudes expected scientists to come up with different scientific results, so they did. Think of a society-wide version of corporate-sponsored research centers that are expected to massage the results until they match the desired outcome.
Another thing is that sometimes it might be beneficial to believe something that isn't true. If you knew for a fact that tomorrow 99% of population will suffer extremely painful death then from the point of view of an individual the correct move would be to commit painless suicide, but the survival of humanity relies on everyone believing they'll be all fine. This is obviously a caricatural example, but there are lots of such lies that keep the society going, and "we're all equal" is just one of them.
Personally, I find it extremely difficult to believe that we'd be born equal, because evolution works only if some individuals are better than others, and I strongly believe that evolution is a thing.
> Sure, we have 50 years of research proving that children are blank states
No, we don't.
> I find it extremely difficult to believe that we'd be born equal
This is not what the article author claims or ever claimed.
It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value. To do otherwise requires living one’s life in cognitive dissonance; how could they be worthy of such riches while others struggle to just pay the bills? Surely success and intelligence is just an inborn thing, and thus inevitable and unchangeable. There’s nothing they can do, and it was always going to end up that way. Inevitability erases any feelings or guilt or shame.
Ironically IQ is also popular amongst people in a very different situation, that is, people that aren’t actually successful “in the real world” but score highly on aptitude tests. Their high scores serve as an identity pedestal to look down upon others and set themselves apart from the masses. This seems to be the primary demographic of IQ-requirement organizations.
Now of course there are scientific studies on this topic, but let’s not pretend like this is a cultural meme because writers like Cremieux are just tirelessly searching for the truth, no matter what ideological consequences that may have. They quite obviously have a viewpoint first and then work backwards from there to justify it.
As a meta comment: the whole obsession with IQ as a kind of unchanging permanent quality seems very much out of tune with how biological systems actually work, and is kind of a remnant of a Platonic worldview. That is, it’s not dynamic/process/system oriented in the way that nature actually works, but instead is in search of eternal qualities á la Plato.
Smart people tend to have gifted children, this is, unfortunately, factual.
Being smart is a poor proxy for success, you have to have access to the right knowledge and resources at the right time, and often the “smart” move is short term.
It could be argued (and often is), that the reason intelligence is strongly predicted based on heritage (though of course: not guaranteed) is due to your parents interactions with you as a child.
like many things, I’m not qualified to answer.
Sufficed to say that some of the smartest people I personally know are more limited in their success than some of the confident yet much less intelligent people I know: who seem to be, in general, much more successful.
The correlation between success and intelligence is as you say highly circumstantial. There are few areas of endeavor where intellectual prowess is the determining factor—normally persistence, luck, and resources are more determinant.
That said, the experiences of my youth in animal husbandry make me a strong believer in genetic determinism.
It is empirically practical to use breeding alone to predict cognitive abilities, behaviors, tendencies, and elicitable capabilities in animals, given identical rearing environments. Right down to nervous ticks, inherent fears, very specific nuisance behaviors, as well as predictable desirable behaviors, dispositions, and fascinations. Even preference for certain types and even colors (shades?) of toys over others. The fine grained nature of determinism in behavioral tendencies is remarkable.
There is so much overlap of structure and function within mammals that it is extraordinary to claim that apes are somehow exceptional by categorically fundamental properties rather than degree.
Great apes are much more adaptable and capable than most animals, and environment probably plays a much greater role in our development because of the power of our faculty for learning, but that does nothing to negate the underlying heritability of extremely fine grained cognitive traits.
Animals are in no way blank slates when they are born. Genetic or in-utero programming plays a huge role in cognitive processes, and cognitive capacity is a direct dependent of physical structure.
One does not predict the other necessarily, but there is still a difference between a partially full mug and an overflowing shot glass, even if they hold the same volume in practice.
We are born with unequal capacities in both physical and cognitive realms. It is an uncomfortable truth. We do ourselves a disservice when we try to pretend inconvenient things are not so just so we don’t have to face uncomfortable choices.
If true, this doesn't say anything about heredity though. It could just as well be all about environment and smart people carrying the same kind of environment on.
Yes, I made that point.
> It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value.
I agree that that could be a motivation. But I would also say that having a motivation for a given result doesn't preclude that result. That is generally true in science.
I'm not an expert. But there seems to be fairly overwhelming evidence that some significant amount of intelligence is heritable. That IQ is a reasonably good measure (or proxy) for intelligence. And that IQ correlates well with a lot of other things like educational attainment and income.
That doesn't mean that your genes determine your future. But it does suggest that some people are "born" in a better position than others -- aside from their socio-economic status.
This shouldn't be controversial. Height is well-known to be heritable. Being tall gives you a better shot at making the NBA. The same is true for many other things.
> This shouldn't be controversial. Height is well-known to be heritable.
I don't understand why so many commenters here are arguing against a straw man. The article author does not and never did believe in the "blank slate" theory. The author has a "centrist" view that genes matter but are not the only determining factor.
I was responding to the previous comment, not so much the article.
> The author has a "centrist" view that genes matter but are not the only determining factor.
Nobody thinks genes are the only determining factor (that's a straw man on the other side :)
Most people agree it is somewhere on a continuum. Some people think it leans more one way; others the other way. Some people want it to lean more one way; others want it to lean more the other.
I'm not reacting against the article, but the people mentioned in the article that the author is critiquing.
> It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value. To do otherwise requires living one’s life in cognitive dissonance; how could they be worthy of such riches while others struggle to just pay the bills?
It doesn't require any such thing. It doesn't take a super genius to understand the roles of chance and circumstance have on one's lot in life.
I agree it doesn’t take a super genius to understand that, but it does require something like deep emotional intelligence and ethical sense for someone immensely successful to truly accept that chance and circumstance may be largely responsible for their success.
There aren’t a lot of billionaires out there acting in a way that shows this. At best, they give the idea some lip service.
> There aren’t a lot of billionaires out there acting in a way that shows this
What would that be?
Complex question that depends on one’s ethical views, but I’d say not pushing the idea that inequality is good, or retweeting people that are obviously ideological making heritability claims, is a good start.
From there, the sky is the limit. Directly helping underserved communities access the same networks/resources is another. A handful of billionaires have also donated their entire wealth, but the laudability of that depends on your ethical stance of course.
I don't see how lack of either of the suggested options is any kind of indication that the person doesn't accept that success has a factor of chance.
I doubt there's even a claim that this is right ethically or that you are not displaying a hipocrisy here. How far is your own wealth from the worldwide median?
I really don’t understand what point you’re trying to make.
That someone could be a billionaire, spend their time writing essays about how inequality is good, retweet and give attention to people insisting that intelligence and success are mostly inheritable – and yet also deeply understand that their success is largely dependent on chance? Uh, I guess such a person could exist, but it seems like you’re just nitpicking here.
And of course there is an obvious ethical claim here: that people who benefit from a system and become wealthy should feel some sort of ethical obligation to contribute to or improve access to that system. Or at least not actively try to deny that such a system helped them. This is a complicated topic which is why I said “depending on one’s ethical views.”
No idea what my personal situation has to do with this, but I assure you, I’m not a billionaire, nor am I wealthy, unless merely being born in a Western country implies that one is wealthy (a nonsensical claim.)
> the idea that metrics like IQ point to some sort of “universal independent” metric of value
What’s particularly annoying is that this can so easily be proven false. No amount of heritable IQ points are gonna help if you’re born to a starving family escaping genocide in Sudan.
But also, “IQ” has been a useful characteristic for a few decades to maybe a few centuries at most. For most of human existence, pure physical strength was likely much more useful than the ability to do abstract thinking.
So even if we accept all these easily disproven ideas, it’s still clearly evident that the fact that they’re in a position to benefit from these supposedly heritable traits is only because they happen to be extremely fortunate to be born in a time and place where these traits are actually valuable.
Several 9s of humans that ever existed would have found an Einstein level of genius worthless
There's also the problem that many "IQ" tests are heavily biased toward a Western, Anglophone education.
Being able to correctly say, for instance, which of four options a "façade" is most like has nothing to do with inherent intelligence; it has to do with whether you were taught the meaning of the word "façade", and the four (often somewhat uncommon) words presented as the choices. The same is true for any of the questions that are, even in part, testing your vocabulary.
Presenting such a test to two people, one of whom was educated at a private school in New York City, and came from a family that highly valued reading and education, and the other at a public school in rural upstate NY, and came from a family that thought it was "too woke" for boys to read books, it is painfully obvious which one will do better, regardless of any genetic factors.
> It’s not that surprising that many successful people seem to be strong fans of heritability, or more broadly, of the idea that metrics like IQ point to some sort of “universal independent” metric of value. To do otherwise requires living one’s life in cognitive dissonance; how could they be worthy of such riches while others struggle to just pay the bills? Surely success and intelligence is just an inborn thing, and thus inevitable and unchangeable. There’s nothing they can do, and it was always going to end up that way. Inevitability erases any feelings or guilt or shame.
I've never understood the idea that winning the genetic lottery somehow makes a person more "deserving" or "worthy" than another. To me, the whole idea of "meritocracy" is a moral abomination.
How do you understand meritocracy? It seems natural that those that do valuable things get rewarded a lot.
Ideally everyone would get the same chances to do valuable things but that's not how the world is setup. Unfortunately.
However trying to change that must be done with care as it's easy to increase injustice (looking at most communist systems)
> It seems natural that those that do valuable things get rewarded a lot.
I'm not fond of the term "rewarded." I understand how prices are determined by supply and demand in economics. Obviously in the labor market, some skill that is in high demand and/or short supply will bring a high price. However, economics are largely amoral. The economic system is not an ethical system to reward the worthy and punish the unworthy, just a method of distributing resources.
There's both an uncontroversial and a controversial interpretation of "meritocracy." Uncontroversially, those who are best qualified for a job should do that job, especially for life-and-death jobs like in medicine. This is how the argument usually starts, with the uncontroversial interpretation, but then it slyly shifts to the controverisal interpretation, that certain people "deserve" more money than others, often a lot more money, due to their qualifications. And while we may want economic incentives for the most qualified people to persue certain jobs, overall it doesn't appear to me that the economic incentives align with societal benefit. For example, we massively reward professional athletes and entertainers much more than doctors and nurses.
Ultimately, the controversial notion of meritocracy is used to justify enormous disparities of wealth, where a few people have so much money that they can buy politicians and elections, whereas others are so poor that they have trouble affording the basics like food, shelter, and medical care. And supposedly that's all based on "merit", which I think is crap.
When I was an undergrad (or maybe it was grad - it was a long time ago) we learned about the Minnesota twins study that attempted to find the strength of genetics in personality. The study developed new statistical techniques to measure this and can to the conclusion that genetics is very strong.
But now you hear nothing about this study. I'm not sure if it's because the results are tainted by eugenics, or if the techniques they developed were wrong...
You hear something about it if you run the article through a screen reader. :-)
I started the article but couldn't get past the conceit and name-dropping in the first couple of paragraphs. I just went back and tried to skim through it and gave up again after a couple of more paragraphs.
What you call name-dropping is justified by the need to clarify the stakes and be transparent about where the criticism is coming from. If the article is too long for you & you're already familiar with the notion of heritability, you can go directly to the "The Dog Eat My Control Group" section near the end.
(David Bessis is a fan favorite here, and Paul Graham makes an appearance.)
Related, from last year: https://news.ycombinator.com/item?id=42200209
You can see this type of thinking in the absolute certainty that the YC interview process finds every billion dollar company that apply. I’m unconvinced and think a lot of the people who joined those early batches and made so many great companies were changed by their environment not by being filtered for credentials or genetic gifts.
Re: Von Neumann IQ Pill
https://archive.ph/6tOQF
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For full clarity: I didn't flag your comment (at least, not intentionally, as I never even thought about doing that)
Now the substance:
"The alleged “suppressed control group” does not turn the result into “no heritability”."
=> Of course not, did anyone claim there was no heritability? But
1/ It's not "alleged", it's printed black on white in the paper.
2/ There is no excuse for suppressing control group data (it's like suppressing the placebo arm of a drug study).
3/ It does turn the result into "junk", and it does establish a definite case of scientific malpractice among people arguing that IQ heritability is 0.70.
As for later analyses, they weren't the topic of my post, but that doesn't mean they're casher.
As for this snide comment that you posted behind your flagged comment:
"I don't care if you find it fair. If you can't accept that genetics determines the entire organism (stress: entire) and does not stop at the neck, then you'd perceive my later criticisms as much worse than - gasp! oh great heavens! my pearls! - unfair. It is a bitter pill to swallow that some people were simply born with better hardware than yourself, one you are obviously railing against. Now, rush on and down vote this comment as well to lighten the burden of your cognitive dissonance. I'm also finding it difficult to reconcile your use of the flag/report on the parent comment versus the rules dictating and describing what is disallowed content. Disagreement is not against the rules. Perceived "fairness" is not in the rules."
Sorry to inform you that you don't understand the meaning of the verb "determine", as "genetics determines the entire organism" is scientifically wrong for obvious reasons: "influences", yes; "encodes proteins for", yes; but "determines", no.
And, no, I'm not railing against anyone's hardware as I'm pretty satisfied with mine.
In contemporary human populations living in typical modern environments, a large share (roughly half or more in adulthood) of the differences in IQ between individuals is associated with genetic differences.
The evidence is overwhelming in that direction:
Twin & family designs: h² ~0.4–0.8, often ~0.7–0.8 in adult samples like MISTRA.
Adoption: people resemble their biological relatives more than their adoptive relatives in IQ, despite strong environmental differences.
Molecular genetics: polygenic scores and GCTA show real, replicable genetic signal for intelligence.
What it does not mean is that:
1. IQ is fixed at birth in a way that cannot be influenced by environment.
2. IQ differences justify any sort of discrimination or moral ranking.
Those two points are where people tend to clutch their pearls and panic. Just because we have noticed an uncomfortable truth does not mean that it is valid to use it in a discriminatory manner; the issue becomes that people will inevitably do so, thus those "in power" cripple the theory in the crib so as to avoid the fearful and uncomfortable implications.
This literally doesn't say anything. It's a lot of words, but you've managed to reproduce the exact position the author of the article has. For those wondering what the trick was here: this comment forwards the 40-80% h2 numbers from twin studies, then says "molecular genetics show real, replicable genetic signal for intelligence", rather than showing the 10-30% h2 numbers those studies generate.
It's practically nobody's position that there's no linkage between genetics and intelligence (that would be weird indeed), but it's important for this comment for you to believe that's the counterargument --- otherwise the comment doesn't make sense.
The real question is whether genetics is a substantial or a negligible influence on intelligence (or proxy measures like IQ).
If genetics is less than 5 percent I would consider that something worth ignoring.
If it is 10 percent it is substantial enough to make a difference at the extremes.
If it is 20 percent that is real serious business.
Anything higher means we should really sit up and take notice of this fact.
Another issue is, what is it that you're trying to use it for?
If you're arguing against a eugenicist then it's not just about the percentage, in that case you have to distinguish between genetic and heritable. Suppose that there are some set of four genes that, in just the right combination, are worth 5 IQ points. That's, by definition, genetic, but it won't have a strong correlation with heritability because every kid has four chances to get the combination wrong. Or, if the combination does something bad, four chances to get it right even if their parents didn't. So past performance is no guarantee of future results.
By contrast, if you're trying to decide whether to allocate more resources to kids who already show promise, you care about the individual's natural potential rather than the statistical probability that it will be similar to their parents, so it doesn't matter what was more likely, it matters what actually happened. And by the point you're performing the evaluation, you can't go back in time and change things like the prenatal environment for someone who is already born, so in that context those things belong in the "nature" column and "nurture" only gets the things you could still affect.
Please look at the examples in the article and consider re-calibrating your numbers here. The lower range of heritability means that it is mostly noise.
Why is that? Odd that the article claims otherwise:
> 50% may sound like a solid heritability figure, but the associated correlation is rather modest.
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Which exact passage of my piece triggered this bizarre interpretation? What made you jump from "someone criticizes a 1990 paper in Science for withholding critical control group data" to "this person is subject to magical thinking"?
As it happens, I often run into trouble due to my conceptualist views on the foundations of mathematics (that is, I'm a hardcore physicalist & anti-Platonist cognitivist, which is quite rare among mathematicians), so I find your criticism particularly unfair.
I don't care if you find it fair. If you can't accept that genetics determines the entire organism (stress: entire) and does not stop at the neck, then you'd perceive my later criticisms as much worse than - gasp! oh great heavens! my pearls! - unfair. It is a bitter pill to swallow that some people were simply born with better hardware than yourself, one you are obviously railing against. Now, rush on and down vote this comment as well to lighten the burden of your cognitive dissonance. I'm also finding it difficult to reconcile your use of the flag/report on the parent comment versus the rules dictating and describing what is disallowed content. Disagreement is not against the rules. Perceived "fairness" is not in the rules.
Not a word of this responds to the article itself; it's just a series of subjective judgements you've made about the author and have decided to argue about instead. Always the hallmark of a strong position!
user: jagoff
created: 1 day ago
karma: -3
everything you need to know in a nutshell. username itself even has an implication.
I think it's pretty funny that no matter how straightforward the methodological critiques of 90s-vintage twin studies are, they always elicit responses as if the critiques were metaphysical, rather than (for instance) deliberately excluding the dizygotic twin control group from MISTRA because it revealed the studies findings were just noise.
The truth is, for these kinds of studies, the whole enterprise might as well be metaphysical; people saying these kinds of things have formed a religious conviction about the heritability of behavioral traits, and their real objection is that science continues to be done on the topic at all. Ironic, given the frequency with which they complain that this science is suppressed.
(I too have a near-religious conviction about this subject, though in a different direction; I do not, however, pretend that conviction is itself a methodological critique!)
I, and clearly many others based directly on your comment assertion, clearly disagree.
Whether or not you like MISTRA, “they left out the non-identical twins” is a side issue, and the broader evidence that IQ is substantially heritable is extremely strong.
Even if DZA were excluded, MZA alone provides a solid heritability estimate. The DZA sample was small and noisy, and MISTRA uses other twin and family data. Plus, meta-analyses confirm high IQ heritability, typically 0.5-0.8; Later structural-equation models applied to the full MISTRA cognitive dataset (MZA + DZA) estimated the heritability of general intelligence around 0.77, essentially the same ballpark as the original simple estimate. laplab.ucsd.edu. Intelligence is highly heritable, potentially reaching 80% in adulthood, supported by further studies like the Haworth et al. meta-analysis, showing age-related increases in heritability.
Strong evidence for polygenic and SNP heritability is shown from Plomin & von Stumm's 2018 research, showing how polygenic scores predict general intelligence.
Adoption studies further support the genetic influence, as adoptive siblings show weaker correlations compared to biological ones.
Environment is certainly NOT outweighed entirely or beyond merit, but evidence clearly shows the "uncomfortable" result having strong support despite desperate attempts to debunk.
In short; the op's story only works if including the DZA data actually drags the heritability estimate down into trivial territory. It does not.
Later analyses of the MISTRA sample that explicitly include both MZA and DZA twins and use full structural-equation models estimate heritability of general intelligence (g) at about 0.77 in adults. https://laplab.ucsd.edu/articles2/Lee2010.pdf
That is higher, if anything, than the original approximate 0.70. In other words:
The alleged “suppressed control group” does not turn the result into “no heritability”.
The more sophisticated models using that very same DZA data still say “IQ differences in this adult sample are heavily genetic.”
You just don't like this data, and don't want to accept it, because of the implications.
I think you may have mistook me for asking for a gish gallop of intelligence arguments, rather than simply pointing out that you ignored the substantance of the article's methodological critique. Which: the comment you wrote upthread is right there for everybody to read.
In my mind, the bigger issue with twin studies trying to show that (say) IQ is highly genetic is that humans do not reproduce by cloning. And regression toward the mean is very much a thing for heritable traits.
In other words - Junior should not be presumed to be smarter, fitter, more deserving, or destined for success, just because his parents did well. No matter how attractive that conclusion might sound, to people who consider themselves to be the "better" sort.
That doesn't sound like a problem with twin studies exploring the degree to which IQ is genetic, that sounds like a problem with people treating aggregate tendencies and associations as a basis for individual discrimination.
Yes-ish. Hence my use of "issue".
The problem is most people's zealous desire to read socially self-serving conclusions into any data they can find on such subjects. And when they really like the Q.E.D. punchline, humans have very low standards for the "logic" used to reach it.
"most people's zealous desire to read socially self-serving conclusions into any data they can find"
what planet are you living on?
also your comment was completely incorrect and missing the entire point of twin studies.
iq is "polygenetic" with the consensus estimates at 50-80% based on genes
success has components of luck as in "right place, right time" for someone with the right qualities and connections, and many of the very successful are quick to admit this
I am a 3rd generation machinist along the paternal line, and although the machines I operate are in expensive labs, those my father and grandfather operated were probably just as challenging. Engineering also seems to often run in the family. How much is nature and nuture? "It varies" is a safe response
Whoah, no, there is definitely not a consensus for 50-80%, and most of what's being published now refutes the 80% end of that range --- the 80% estimates come from underpowered studies like MISTRA that improperly assumed independent environments for twins reared apart.
okay, I saw the paper saying 500 genes are involved. So does a single number for iq mean anything? Does the number depend upon what is tested?
We have essentially no mechanistic understanding of gene/intelligence interactions. Rather, we have cohorts of people tagged with traits (educational achievement, tested IQ, height, etc), all sequenced, and then we can run correlation surveys across all their genomes to identify correlations between alleles and traits. When you do that, you get 10-30% heritability numbers; the gap between that and the range for MZ/DZ twin studies (the 50-80% you often see) is "the missing heritability problem".
Regarding missing heritability: https://www.astralcodexten.com/p/the-good-news-is-that-one-s...
"That is, once you include the rare variants, the amount of genetic variation that “should” exist but doesn’t shrinks to only 12%. Plausibly an even bigger study, investigating even rarer variants, could shrink the gap further, all the way to zero."
Of course, even then heritability will not be 100%.
does epigenetics play a significant role? Within one lifetime or several generations?
Way above my pay grade. Probably! Or probably not?
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