Explanations of differences in IQs of Northern and Southern Blacks focus on selective migration (hereditarians) or environmental causes such as education, discrimination and cultural deprivation. In this paper the environmentalist position is questioned and certain neglected features of Lee's data are construed as providing strong evidence for…

Extensive data on twins, nontwin siblings, siblings separated by adoption, and parent-child similarity indicate that the heritability of intelligence is closer to .50 than to .70. Differences could be due to environmental or genetic changes in the population, or to methodology. (Author/CP)

This book contains papers that discuss the "g factor" (general intellectual capacity) in discerning intelligence and how to influence the development of intelligence. The g factor relates to the theory that individuals who do well on one mental ability test tend to do well on other mental ability tests due to an innate ability. Chapters…