[tptacek]

Molecular and behavioral geneticists absolutely, in modern studies, attempt to deconfound heritability statistics. Within-family and sibling regression are two of those techniques. When you use those study designs, heritability plummets for IQ, but not for traits like height.

I'm not trying to stake out a position about whether IQ is in any sense genetically causal or fixed. I'm saying that it's much more complicated than the Wikipedia page on "Heritability of IQ" would suggest. That's the only reason I dipped into this thread. You can believe whatever you want to believe, but this is an actively (indeed, furiously) studied open question, and the answer is definitely not "twin studies from 20 years ago set a heritability number that resolves the question".

[Dylan16807]

I know it's complicated, but you seemed to be arguing pretty strongly that the genetic component is zero which while possible is not well supported by the evidence.

If you're not trying to stake out a position then you did a very good job of convincing me otherwise.

I don't know where I implied it wasn't complicated?

Also my original statement was just that it's "entirely reasonable".

[tptacek]

I think if you read the thread history you'll see that I said nothing of the sort. But a conclusive answer to the question of how much direct genetic influence there is on intelligence (outside of disease/disability genetics) is very much not supported by current evidence. It's an open question. Right now: it's not looking great for the hereditarians (define them as "there is a very strong genetic component to cognitive ability"), but that could change as molecular genetic methods improve. Nobody knows.

[Dylan16807]

> I think if you read the thread history you'll see that I said nothing of the sort.

You said "the sort we have numbers from peer-reviewed articles on" is "not genetically causal". https://news.ycombinator.com/item?id=45624902

That's not true. There is peer-reviewed evidence for genetic causation.

[tptacek]

I don't know what you think that means, but if you took "peer reviewed evidence" from the 1990s as scientific truth, you'd arrive at an answer that is outside the mainstream of even hereditarian scientists today. Further, things like twin studies can't be evidence of genetic causation. I gave an example of why not upthread.

I think we are way too deep in the weeds for this to be productive, and we're the only two people reading this. If it wasn't clear, I was trying 1-2 exchanges ago to find an off-ramp for this. I'm not telling you what to believe, I'm just saying that twin study heritability statistics don't settle the question. We should be able to agree comfortably there.

[Dylan16807]

Some of the studies linked are from the last ten years, but whatever I think we've explained our positions well enough at this point and there's not much use in continuing.

[tptacek]

(I inadvertently edited my comment after you wrote yours --- I just forgot to hit the "update" button. The first graf is the same, but the second graf appeared on the thread after you wrote yours. Just for the record, for anybody that might happen to read this.)

Have a good weekend!