This is the latest in a series of reported findings for a Guidance Study which followed the same persons from infancy to age 40. The report focuses on: (1) how well the 50 men and 60 women subjects maintained their positions relative to I.Q. during the 22 years since they were last tested at age 18; (2) gains and losses in I.Q. over the 22 year…

Much of our thinking about contemporary social problems reflects tacit presuppositions regarding the operation of heredity and environment in human behavior. These beliefs have important implications for practical decisions. Advances in genetics, psychology, anthropology, and other disciplines have contributed much to a clarification of the…