Examined the interrelations of group contextual factors and the occurrence of aggressive behavior in 22 experimental play groups of 7- and 9-year-old African American boys. Found that negative affect, high aversion behavior, high activity level, low group cohesion, and competitiveness were related to the occurrence of aggressive behavior. (MDM)

Investigated the relationship between peer group identification and similarity between individuals involved in problem behavior, and whether group identification moderated group influence on development of delinquent behavior among Italian sixth- and seventh-graders. Found that group behavior interacted with reciprocity of group nominations in…