Ronald C. Johnson argued that if early environmental stimulation or deprivation has a significant effect on intellectual ability, then individuals who are genetically identical and who are exposed to a common early environment should resemble one another more closely in IQ than similar individuals who have not shared a common environment. Johnson…

In this response to the critiques by Jensen and McVicker Hunt, we focus on the meaning of g, the permanence of effects produced by early education, and the educational significance of IQ gains produced by early education programs. New longitudinal data from our study presented. (Author/RD)

Ramey and Haskins report two findings of major importance: absence of decline in test scores and absence of mother-child correlation for treated children. Implications of these findings are discussed. (Author)

Infants judged to be at risk for subnormal intellectual growth were randomly assigned to experimental and control groups which varied as to educational curriculum activities. Two types of evidence, group differences and parent-child IQ correlations, demonstrate the importance of early environments in intellectual development. (Author/RD)

Infants judged to be at risk for subnormal intellectual growth were randomly assigned to an experimental (N=27) or a control (N=25) group. Infants in both groups received medical care and dietary supplements; their families received social work services on a request basis. Experimental children participated in an educational day care program…