The identical twins in these studies would have been reared in similar environments and cultures by different adoptive parents. The case I quoted were hunter-

The identical twins in these studies would have been reared in similar environments and cultures by different adoptive parents. The case I quoted were hunter-gatherer vs. farmers. Notice the difference. I was arguing, not that there's a genetic component, and an environmental component, but that the two are interlinked: different alleles can make different individuals well adapted in different enviroments. In an modern developed economy, where you'll be more likely to do well if your IQ is high, some people will have inherited alleles which tend to raise their IQs and make them well-adapted to their environment, others different alleles which make them poorly adapted. And, on top of that, there's an environmental, or rather cultural component.