GENETIC AND ENVIRONMENTAL ARCHITECTURE OF HUMAN-AGGRESSION

A meta-analysis was performed on data from 24 genetically informative studies by using various personality measures of aggression. There was a strong overall genetic effect that may account for up to 50% of the variance in aggression. This effect was not attributed to methodologi cal inadequacies in the twin or adoption designs. Age differences were important. Self-report and parental ratings showed genes and the fami ly environment to be important in youth; the influence of genes increa sed but that of family environment decreased at later ages. Observatio nal ratings of laboratory behavior found no evidence for heritability and a very strong family environment effect. Given that almost all sub stantive conclusions about the generics of personality have been drawn from self or parental reports, this last finding has obvious and impo rtant implications for both aggression research in particular and pers onality research.