A behavioral genetic investigation of aggression in intimate relationships

To date, the most widely accepted theory to explain aggression in intimate relationships is social learning theory. Because aggression against intimates tends to run in families, this theory posits that children learn how to behave aggressively through watching their parents and through being reinforced for their own aggressive behaviors. In other words, the documented familial resemblance for intimate aggression is taken as evidence that intimate aggression is acquired via social learning mechanisms. A strict social learning account of intimate violence considers only environmental influences on familial resemblance; although never before examined, familial resemblance for this behavior could also be due to genetic factors. The current study uses a genetically sensitive design to examine the extent to which genetic and environmental factors contribute to individual differences in intimate aggression. Questionnaires regarding the use of aggressive behaviors in intimate relationships, personality, and attachment styles were completed by 185 twin pairs (144 MZ, 41 DZ).;Model-fitting analyses consistently showed that shared genes, not shared environments, explained the familial resemblance in these aggressive behaviors. When familial resemblance was shown, genetic influences accounted for between 13% and 43% of the variance in the use and receipt of physical aggression and between 22% and 42% of the variance in the use and receipt of psychological aggression; the remaining variance was explained by unique environments. The use and receipt of aggression were highly intercorrelated, and 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. Finally, genetic influences on intimate partner aggression were not mediated by genetic influences on personality or attachment styles.;The finding that familial resemblance in intimate partner aggression is due to genetic, not shared environmental, factors challenges the prevailing theory of the intergenerational transmission of intimate partner aggression. Furthermore, this study provides an important focus for researchers interested in environmental influences on intimate partner aggression. Instead of examining environments that are shared by family members, researchers should focus on environments that are unique to individuals within each family.