IQ, scholastic performance and behaviour of sibs raised in contrasting environments.

Medium- and long-term effects of types of placement of the offspring of lower class families have been studied. The progeny of 28 mothers was reconstituted. The subjects were divided into three groups: 35 children abandoned and adopted early in privileged environments (A), 46 'biological mother-reared' children remaining in their disadvantaged social environments (B) and 21 children raised in institutions or foster homes (C). Analyses focused on IQ, scholastic performance and behaviour. Results show that the social environment has important effects: the differences between the three groups are very significant. For A and B groups tested in the schools, comparisons were made with the classmates. For the C group the effects of long-term emotional deprivation are superimposed on the effects of the social environment.