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.

@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.

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

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.

@bitofhope @swlabr

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.

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.