Individual differences and the canalization of human behavior

Gottlieb (1991) suggests that behavior geneticists and developmental psychologists have underesti-mated the importance of environmental regulation of species-typical behavior, outlines a theory of how environments and genes interact dynamically as behavior develops, and provides supporting examples from his own and others ' laboratories. Although oversimplified explanations of develop-ment have occasionally gained currency, we contend that the complexities of genotype-environ-ment relations have been addressed in psychology, with still greater difficulties arising from psy-chologists1 interest in individual differences in behavior. The complexities of studying genetic and environmental determination of the development of individual differences are explored, using intelligence as an example. Finally, we outline a research program in the spirit of Gottlieb's contri-bution. Variety is said to be the spice of life. It is a staple of necessity to geneticists. (Dobzhansky, 1967, p. 42). Man is not just an overgrown Drosophila. (Dobzhansky, 1967, p. 47) Gottlieb (1991) has provided a thoughtful and provocative se