Peer Factors as Mediators of Relations Between Exposure to Violence and Physical Aggression in Middle School Students in a Low-Income Urban Community.

Objective: Although prior research has demonstrated that peers influence both physical aggression and exposure to violence during adolescence, few studies have investigated the extent to which peers play a role in relations between physical aggression and violence exposure. This longitudinal study examined peer pressure for fighting, friends' delinquent behavior, and friends' support for fighting as mediators of relations between exposure to violence through witnessing and victimization, and adolescents' frequency of physical aggression.

Method: Participants were 2,707 adolescents attending three urban middle schools (Mage = 12.4; 52% female; 79% African American, 17% Hispanic/Latino). Participants completed measures of their frequency of physical aggression, witnessing community violence, victimization by violence, and negative life events, and peer variables at four waves within the same school year.

Results: Cross-lagged analyses indicated that the role of peer variables as mediators varied as a function of the type of exposure and the direction of effects. Whereas peer pressure for fighting mediated relations between witnessing violence and changes in physical aggression, friends' delinquent behavior mediated relations between physical aggression and changes in witnessing violence and victimization. In contrast, violent victimization was not associated with changes in any of the peer factors when included in the same model as witnessing violence.

Conclusions: These findings highlight the role of peers as both a cause and a consequence of adolescents' aggressive behavior and exposure to violence. They suggest focusing on peer variables as targets for interventions to disrupt connections between exposure to violence and physical aggression during early adolescence.