The present proposal will test a family-based emotion regulation model of continuity in childhood antisocial behavior from preschool to middle childhood. Observational assessments of marital, parent-child and child-peer systems and physiological assessments of sympathetic and parasympathetic nervous system activity will be systematically applied in one study to examine interpersonal and intrapersonal risk factors that are associated with stability and change in antisocial behavior. A previously recruited sample of 130 families with preschool aged children (4-5 years old) will be seen again at ages 9 and 10. A new cohort of 95 families will also be added, with assessments at age 5, 9 and 10. Physical marital aggression, individual parental emotion regulation abilities, parenting skill deficits, parental meta-emotion philosophy, children's sensitivity to conflict, and children's physiological regulatory ability will be proposed as constructs in theory testing. A hypervigilance model in which exposure to physical marital aggression may be associated with hypervigilance to threat is tested and mechanisms of linkage are articulated. A competing model, a habituation model in which physical marital aggression is associated with habituation to threat, is also tested. The present proposal also seeks to: (1) examine developmental changes in physiological functioning in conduct-problem children across the developmental period from early to middle childhood; and (2) test for gender differences in the family-based emotion regulation model.