THE MASSACHUSETTS TWINS AND SIBLINGS SOCIAL ADAPTATION PROJECT (MATSSAP): AN INTRODUCTION AND PRELIMINARY FINDINGS

Lisabeth F. DiLalla

Southern Illinois University School of Medicine

Presented to the Behavior Genetics Association, Keystone, CO, July, 2002

ABSTRACT

Inclusion of genetic effects in developmental models of aggression is necessary for understanding how environmental influences, such as parental discipline or peer delinquency, interact with individual differences, such as temperament or physiological responses to novelty, to lead to aggressive outcomes. This pilot project of 47 twin pairs begins to address the question of whether there are different etiologies for different forms of aggression. Preliminary results suggest that proactive aggression may be heritable. Similar trends were evidenced for reactive and relational aggression as well, calling into question the degree to which these forms of aggression are distinct. A larger sample size will allow further exploration of the different etiologies of these forms of aggression, as well as the degree to which each form shares genes with different personality traits, such as emotionality, attention span, and sociability.