Emil O W Kirkegaard

So that implies that the US systemically depressed the IQ of african americans by denying them wealth and education and segregating them from the rest of scoeity and the ability to reproduce with other groups for the past 200 years?

because if high iq people reproducing with high iq people creates a new, higher "genetic mean" than obviously the inverse must also be true -- separating lower iq people from the general population would necessarily create a new, lower "genetic mean" among that population.

Segregating the B/W populations in the U.S. would certainly affect the means to which traits regressed -- if the genetic means are different. I think in the U.S., selecting mates based on IQ is only a recent phenomenon (1 or 2 generations), outside very wealthy families.

These strike me as contradictory: (1) High % of AAs have Igbo ancestry and went through slavery, have avg(iq) ~85 (2) Self-selecting immigrants have high IQ and create a high-mean subgroup, having kids with IQ (3) IQ is strongly heritable and minimally impacted by environment

The mechanism you describe -- high IQ people reproducing with high IQ people to create a new subpopulation with a higher mean -- would take numerous generations to actually work. the first generation at least would be expected to regress towards the population mean.

Regarding (1), you have to look at genetic relatedness. Statistics like "have at least one ancestor from population X" aren't really useful here; especially if the one ancestor is like five or more generations back.

And of course it should be obvious that modern self-selection of immigration on one hand, and the forced selection via slavery on the other hand are hardly comparable. And it's not that IQ is minimally impacted by environment; it's shared environment that has minimal affect.

Would it be fair to conclude that, regarding the B/W IQ gap, that if it was constructed by successive generations of forced selection, that we really can't expect that the one/two generations that have come into existence since Jim Crowe would see drastic improvements?