“Your argument essentially boils down to ‘there’s too many confunding factors to be able to reliably estimate heritability of IQ’.”
I think it’s stronger than that. There is a single coefficient of heritability when the right model is (trait) = (genes) + (environment). If the right model is non-additive, the coefficient of heritability just isn’t well-defined. You might still hope that the deviations from this model are small enough that it holds as a reasonable approximation, but that needs to be supported with evidence, and results like Turkheimer’s show that this is going to be hard to do. Once those obstacles are cleared, then you have to confront confounding.
“But your arguments apply equally well to estimating heritability of almost any human trait”
Yes.
“Which to me means there has to be a better way to get to the bottom of this.”
I agree: it’s experimental biology and experimental psychology.

As for your examples, they leave me puzzled. You evidently care greatly for precision and rigor, and I presume are not one to strain out the gnat and swallow the camel. Yet in all the cases you instance, systematic genetic differences accompany systematic differences in culture and in position in social networks, so ugly words like “confounding” and “multicollinearity” spring insistently to mind. They do not go away when I tell them that you want to look at the extremes rather than the averages. In fact, they insist that this path has even more obstacles blocking it than the twin/adoption route. But no doubt all this has already occurred to you, and it’s superfluous for me to point out that a solution to these difficulties would revolutionize the whole field of causal inference. Beside that accomplishment, uncovering the genetic reasons why the Boston police force used to be so heavily Irish — and no doubt the genetic differences dividing the Irish emigrants to Massachusetts from the Irish emigrants to England — will be as nothing. I won’t ask you to risk being scooped by revealing your secret in a comments thread, so I will just have to keep a watchful eye on the journals.

Though perhaps we could learn something about the conditions that nurture talent. Shouldn’t thatreally be the question? Not the essentialist one of who belongs to the chosen clan.

only fools would exclude people from opportunities pre-emptively on the grounds of race, religion, or sex.

Yes, the environment—that of pre-WWI Germany in encouraging people to pursue scholarship no matter what their class background—and Einstein did have the benefit of a very good education—may indeed have contributed to bringing out the latent abilities of the citizenry.

Many working class Brits and Americans by the way, went to Germany in that period to get an education, from which they otherwise would have been debarred in their native countries for class reasons, and many became world-famous scientists.

The moral to be drawn is that one never knows where great abilities may be found and only fools would exclude people from opportunities pre-emptively on the grounds of race, religion, or sex.

And were the Ashkenazi Jews that won earlier last century born in the US or immigrants?

One of the principal reasons the US developed the bomb before Germany in WWII was because the US had all the genius Jewish physicists expelled by Germany working on the Manhatten project.

[Full disclosure: I am not an Ashkenazi or any other flavor of Jew].

Another reason: the US wins more than its fair share of Nobel prizes period, because it has a better environment for research. It may be that the Ashkenazi Jews rose to such great Nobel-winning prominence in the US for the same reason blacks only rise to great running-back prominence in the US: there’s not a lot of NFL played in Africa.

Why didn’t they win equivalent distinctions during over a thousand years residence in Poland and Germany? How come they were “inferior” until the last 100 years?

ie. reeling off half-baked anecdotes and prejudices as in the remainder of your comment above

I picked on these examples for a reason: my gut feeling (details to be worked out) is that you may be able to say something more statistically reliable about heritability vs environment on the basis of outliers than you can based on the performance of the general population.

ie. reeling off half-baked anecdotes and prejudices as in the remainder of your comment above…

Didn’t Wagner write (anonymously) that Jews never could be really good composers—or even achieve anything original at all, since they were cosmopolitan, etc etc.

We also heard that women couldn’t write, or drive cars or jet airplanes, announce the news, and on and on.

Japanese people were not supposed to be able to make anything of high quality. (it is to laugh)

I even remember hearing in my childhood that only white musicians could really play jazz!!

http://www.straightdope.com/columns/050527.html

and so were Colette & Pushkin & possibly St Augustine

Assumes facts not in evidence

Nor should you. The House of Lords is overwhelmingly Protestant. Membership is a highly heritable trait, though not as much so as it used to be.

“That is, if we take a totally random person, we should expect their IQ to be about 15 points from the population average, which another convention fixes at 100. If we take two totally random individuals, then, we’d expect them to differ in IQ by about 22 points [= 15 * sqrt(2)].”

As for distributional assumptions, while I agree that they don’t matter to the discussion, IQs are conventionally assumed to be normal, and no reader would object to that assumption being unstated.

Anyway, more important to me is the thrust of the rest of the post, now that I have read the whole thing.

Your argument essentially boils down to “there’s too many confunding factors to be able to reliably estimate heritability of IQ”. But your arguments apply equally well to estimating heritability of almost any human trait. Which to me means there has to be a better way to get to the bottom of this.

When I watch NFL football and see that nearly every running back is black, I don’t think “those poor white guys growing up in athletically disadvantaged environments”. Likewise when the entire lineup for the finals of the 100m sprint at every major international sports meet is almost always black.

Nor, when yet another Nobel prize is won by an Ashkenazi jew, do I think “those poor protestants, growing up in intellectually disadvantaged households”.

When overwhelming talent percolates out the top end, there’s got to be more going on than just environment.