Genetic and environmental influences on intimate partner aggression: a preliminary study.

Social learning theory posits that, because aggression against intimates runs in families, children learn how to behave aggressively through watching their parents and being reinforced for their own aggression. This theory considers only environmental influences on familial resemblance; however, familial resemblance could also be due to genetic factors. The current study uses a twin design (134 monozygotic, 41 dizygotic) to examine the extent to which genetic and environmental factors contribute to individual differences in intimate aggression. Model-fitting analyses consistently showed that shared genes explained the familial resemblance in psychological and physical intimate partner aggression; the remaining variance was explained by unique environments. Multivariate model-fitting analyses showed that most of the genetic influences responsible for the receipt of aggression were also responsible for its use, suggesting that there is a genetic predisposition to get involved in aggressive relationships. These results challenge the prevailing theory to explain familial resemblance in intimate aggression.