Describes biological influences on criminality. Illustrative data suggest a biological sex difference in criminality and heritable differences in this trait among individuals. Methods of isolating environmental influences are described. Author notes that using environment-friendly behavior genetic research designs is not only proper but would…

Genetic and environmental influences on academic achievement were studied for 314 pairs of white full siblings and 53 pairs of half siblings and 161 pairs of black full siblings and 106 half-sibling pairs (National Longitudinal Survey of Youth). Results support a common heritage view of the growth of academic knowledge. (SLD)

A twin analysis was applied to infants' social behavior in standardized situations that permitted the comparison of social responding to mother and a stranger in different contexts. Twenty-one identical twin pairs and twenty-five fraternal twin pairs were observed in their homes using time-sampled observations of specific behaviors. (Author/SS)

To demonstrate the value of behavioral genetic analysis for developing social theory, the origins of delinquent behavior were studied in 265 pairs of twins. Results show that causal sequences leading to delinquency are traceable to individual differences in genes. These findings, however, do not make sociological research irrelevant. (KH)