The Genetic Basis of IQ

A major theme of The Bell Curve concerns the sources of intelligence. The book was published in the early nineties, about three decades after social scientists began to turn about the idea of the heritability of intelligence along with the notion of intelligence in the first place. For instance, many social scientists held that intelligence testing laid at the root of the eugenics movement and the view that some races, for instance, had systematically lower IQs than other races due to genetic factors had clearly racist implications.

Other scientists were so keen on emphasizing the role of environment in determining intelligence that they came to fracture the very concept of intelligence, claiming that there is no one thing that we mean when we speak of 'intelligence,' but rather a series of socially constructed metrics of skill that are inappropriately combined under the label...