It earned its “flagged off HN” badge in under 2 hours
Science: “our current understanding of genetics leads us to believe IQ is not heritable”.
This fucking guy: “IQ is heritable and you just haven’t proved it yet. Citation: I belong to a race with good genetics, unlike you”
Honestly, I’m really surprised to hear that IQ is not even a little bit heritable, given that IQ test performance correlates with level of education, which correlates with wealth, which is heritable.
True, wealth is not genetic, but heritability has an interesting definition which leads to some unintuitive cases of heritability abd non-heritability. For instance, wearing earrings is heritable while having ears is not.
IQ is heritable and it can’t be fully explained by wealth. Twins raised in different families have a high IQ correlation between them whereas non-twin siblings raised in the same household have far less IQ correlation. This suggests that IQ is likely affected by some combination of genetics and the maternal womb environment much more so than the household environment (where wealth would play a big factor).
Now, the maternal womb environment is not wholly uncorrelated with wealth. Maternal health including lifestyle, activity, and nutrition may play a big role here. Since all of those are positively correlated with wealth, this suggests a potential cause (which still needs to be investigated) of maternal health on fetal brain development and therefore IQ.
IQ is a little bit heritable. But there are plenty of things which are very heritable and also not genetic to use as comparisons, like accents or posture or little societal rituals of communication, compared to which IQ is barely heritable at all. And that’s without cracking into memes/tropes/narremes, skills, maths, or other more-abstract inheritance.
That’s because the HN poster I quoted, like many many MANY people, has conflated predicting iq based off of genes with heritabilty. I’d recommend reading the linked substack, the author’s much more succient and knowledgeable than I am, and I wouldn’t want to misrepresent his point
@bitofhope @swlabr One of those quiet little scientific revolutions; cheap genetic testing let biologists realise that insects they had classified as different species were not, they were different morphs using the same genes. This let in the idea of developmental plasticity and the current consensus is that a whole lot of stuff is developmental, not genetic.
In humans, almost everything brain-based (sexuality, identity, language, symbol manipulation…) is likely significantly developmental.
@bitofhope @swlabr This completely messes with the idea that you can use “good genes” as a guarantee of a desirable outcome.
It also hauls in the idea of environment as the arbiter in more-difficult-to-ignore ways. Even if you’re using Origin and nothing since, you should be aware that “fitness” means “in some specific environment and moment in time”, only there’s this drive to ditch that. Recognising how much developmental plasticity matters breaks any concept of inherent quality of organisms.
If you click enough links, you get to this substack article which I think all the discussion is about. https://theinfinitesimal.substack.com/p/no-intelligence-is-not-like-height
Which indicates that IQ is a little bit heritable, just much less than other traits and with way more confounds.
Which, when you think about the extreme examples, makes sense - if your parents were humans, and mine were golden retrievers, you will be a human and I will be a golden retriever, and you will almost certainly have a higher IQ than me.
… but, apparently, if your parents were particularly bright humans and mine were relatively dim humans, but we then got adopted by the same family and given the same educational opportunities etc., the chance that you will end up brighter than me is only very slightly better than 50/50.
IQ test performance correlates with level of education
I read somewhere that this claim owes a little too much to the inclusion of pathological cases at the lower end of the spectrum, meaning that since below a certain score like 85 you are basically intellectually disabled (or even literally brain dead, or just dead) and academic achievement becomes nonexistent, the correlation is far more pronounced than if we were comparing educational attainment at the more functional ranges.
Will post source if I find it.
@Architeuthis @bitofhope Taleb calls that a “dead man bias,” though I don’t know if he originated the critique. https://medium.com/incerto/iq-is-largely-a-pseudoscientific-swindle-f131c101ba39
