We report a study aimed at understanding the effects of classroom normative influences on individual aggressive behavior, using samples of 614 and 427 urban elementary school children. Participants were assessed with measures of aggressive behavior and normative beliefs about aggression. We tested hypotheses related to the effects of personal normative beliefs, descriptive classroom norms (the central tendency of classmates' aggressive behavior), injunctive classroom normative beliefs (classmates' beliefs about the acceptability of aggression), and norm salience (student and teacher sanctions against aggression) on longitudinal changes in aggressive behavior and beliefs. injunctive norms affected individual normative beliefs and aggression, but descriptive norms had no effect on either. In classrooms where students and teachers made norms against aggression salient, aggressive behavior diminished over time. Implications for classroom behavior management and further research are discussed.

A multiyear, multicontext aggression prevention intervention was provided during the early or late elementary school years in an inner-city and an urban poor community. Sixteen schools were randomly assigned to 1 of 4 conditions: (a) no-treatment control, (b) general enhancement classroom program, (c) general enhancement plus small-group peer-skills training, or (d) general enhancement plus small-group peer-skills training plus family intervention. This article reports on results for the high-risk subsample of 1,500 children. Results from hierarchical linear modeling indicate that comprehensive interventions, if provided in early grades, can be effective for children in schools in settings with resources adequate to support learning and development, but some unintended effects can occur in schools in the most distressed communities when delivered too late in development.

Violence in screen entertainment media (ie, television, film, video games, and the Internet), defined as depictions of characters (or players) trying to physically harm other characters (or players), is ubiquitous. The Workgroup on Media Violence and Violent Video Games reviewed numerous meta-analyses and other relevant research from the past 60 years, with an emphasis on violent video game research. Consistent with every major science organization review, the Workgroup found compelling evidence of short-term harmful effects, as well as evidence of long-term harmful effects. The vast majority of laboratory-based experimental studies have revealed that violent media exposure causes increased aggressive thoughts, angry feelings, physiologic arousal, hostile appraisals, aggressive behavior, and desensitization to violence and decreases prosocial behavior (eg, helping others) and empathy. Still, to more fully understand the potential for long-term harm from media violence exposure, the field is greatly in need of additional large-sample, high-quality, longitudinal studies that include validated measures of media violence exposure and measures of other known violence risk factors. Also, although several high-quality media violence intervention studies have been conducted, larger-scale studies with more comprehensive and longer-term assessments are needed to fully understand long-term effects and to inform the development of tools that will help to reduce problems associated with aggression and violence. The evidence that violent screen media constitutes a causal risk factor for increased aggression is compelling. Modern social-cognitive theories of social behavior provide useful frameworks for understanding how and why these effects occur.

In this article, we test the proposition that identity integration—or perceptions of compatibility versus conflict between one’s social identities—predicts behaviors in intergroup contexts. Using a sample of 171 Muslim Arab American adolescents aged 13 to 19, we examine the relations between identity integration of Muslim and American identities, experiences of discrimination, and intentions to avoid and approach members of the majority group. For adolescents who perceived their American and Muslim identities as being in conflict, we found that perceived discrimination was positively related to intentions to avoid the majority group. However, this trend was not significant for those who perceived their American and Muslim identities as highly integrated. These effects held after controlling for participants’ strength of identification with both American and Muslim identities, and number of years lived in the United States. These results provide support for the idea that identity integration among stigmatized minorities may buffer the negative effects of discrimination on intergroup behaviors.

Information about the degree of one's genetic overlap with ethnic outgroups has been emphasized in genocides, is frequently learned about through media reporting, and is increasingly being accessed via personal genetic testing services. However, the consequence of learning about whether your own ethnic group is either genetically related to or genetically distinct from a disliked ethnic group remains unknown. Across four experiments, using diverse samples, measures and contexts, we demonstrate that altering perceptions of genetic overlap between groups in conflict--in this case Arabs and Jews--impacts factors that are directly related to interethnic hostility (e.g., aggressive behaviors, support of conflict-related policies). Our findings indicate that learning about the genetic difference between oneself and an ethnic outgroup may contribute to the promotion of violence, whereas learning about the similarities may be a vital step toward fostering peace in some contexts. Possible interventions and implications are discussed.