> Current estimates of the "heritability" of intelligence are far, far lower than "0.7 or 0.8"; they're probably below 0.1

Sources please, if you have time? I tried to find something supporting what you wrote, but wasn't able to (this far).

Instead I found this from 2015:

Thinking positively: The genetics of high intelligence, https://pmc.ncbi.nlm.nih.gov/articles/PMC4286575/

They've studied men in Sweden during 40 years. From the abstract:

"We found that high intelligence is familial, heritable, and caused by the same genetic and environmental factors responsible for the normal distribution of intelligence."

"... 360,000 sibling pairs and 9000 twin pairs from 3 million 18-year-old males with cognitive assessments administered as part of conscription to military service in Sweden between 1968 and 2010 ..."

Looking at Figure 3, in that pager, about identical twins and non-identical (two-egg) twins -- I think that settles it for me.

Seems they arrive at a bit above 0.4 as heritability. Yes that's less than 0.7 - 0.8 but I wouldn't say "far far lower", and more than 0.1. Also, they're 18 years old, not adults.

It's been discussed at HN: https://news.ycombinator.com/item?id=10488998

> I'd guess the person you're responding to has thought more carefully about this issue than the median HN commenter has.

Well, in his reply to me, he was sort of name dropping and appealing to (the wrong) authorities, didn't make a good impression on me. Plus writing about himself, but he's a single person. -- I would have preferred links to research on large numbers of people.

> what "heritability" means, which is not generally what people think it does.

That sounds interesting. Can I guess: You mean that people believe that heritability means how likely a trait is to get inherited from parent to child? When in fact it means: (https://en.wikipedia.org/wiki/Heritability) "What is the proportion of the variation in a given trait within a population that is not explained by the environment or random chance?"

My sibling comment (unsuprisingly) goes into more depth and with more sourcing. The 0.4 result you've cited is from 2015, which is in the phlogiston era of this science given what we've learned since 2018. As he has aptly demonstrated: his authorities are sound, and he has thought carefully about this matter --- respectfully, far more than you seem to have. That's OK! We're just commenting on a message board. I wouldn't even bring it up, except that you've decided to make his grasp on the subject a topic of debate.