Richard E Nisbett, an important cognitive psychologist, has published a book on heredity and environmental contributions to intelligence, Intelligence and How to Get It. The NY Times has a review of it that gives us a useful, though partial, update on the state of the debate.
Nisbett emphasizes the importance of a cognitively rich environment for children, and the very unfortunate fact that it tends to be associated with other sorts of privilege, such as social and economic class. Environment does seem to make a different to one’s IQ score, which in turn is also closely correlated with a different in future economic status. This is the clear perpetuation of privilege.
The review also relays a vivid example of the fact that even if differences among individuals were wholly hereditary, it does not follow that differences among groups must be:
The classic example is corn seed planted on two plots of land, one with rich soil and the other with poor soil. Within each plot, differences in the height of the corn plants are completely genetic. Yet the average difference between the two plots is entirely environmental.