The report summarizes recent and ongoing research on processes involved in the development of antisocial behavior disorders in children and adolescents. Studies address both the applied problem of preventing aggressive behavior and the overall relation of cognition to social behavior. A social information processing model of social competence is described, and the results of several studies emanating from this model are noted. Aggressive children are seen as deficient in processing at all five stages of the social information processing model: encoding, representation, response search, response decision, and enactment. A stage model for assessing processing patterns in aggressive children in clinical settings is proposed as a guide to focus intervention efforts. Current research efforts include a longitudinal study on the origins of aggressive behavior which explores whether patterns of deviant information processing are predictive of later aggressive behavior, and whether early family experiences predispose a child to develop deviant patterns of information processing. (JW)