Gladwell summarizes some of James Flynn's findings:
Flynn then talked about what we've learned from studies of adoption and mixed-race children - and that evidence didn't fit a genetic model, either. If I.Q. is innate, it shouldn't make a difference whether it's a mixed-race child's mother or father who is black. But it does: children with a white mother and a black father have an eight-point I.Q. advantage over those with a black mother and a white father. And it shouldn't make much of a difference where a mixed-race child is born. But, again, it does: the children fathered by black American G.I.s in postwar Germany and brought up by their German mothers have the same I.Q.s as the children of white American G.I.s and German mothers.
The difference, in that case, was not the fact of the children's blackness, as a fundamentalist would say. It was the fact of their Germanness - of their being brought up in a different culture, under different circumstances. "The mind is much more like a muscle than we've ever realized," Flynn said. "It needs to get cognitive exercise. It's not some piece of clay on which you put an indelible mark." The lesson to be drawn from black and white differences was the same as the lesson from the Netherlands years ago: I.Q. measures not just the quality of a person's mind but the quality of the world that person lives in.
This seems indisputable to me. The question is whether race has any genetic salience with respect to IQ. And the further question is: if race as genetics and race as environment are hopelessly conflated, as they are in America, what can we actually do about it? Do we have another Lamarckian phenomenon here?