Bridging Disciplinary Boundaries (January 11 - 14, 2007)

Recent empirical and conceptual work has resulted in an ecological developmental framework for understanding and preventing aggression in childhood and adolescence. In this framework, individual and environmental risk processes launch some children onto a developmental trajectory characterized by increased and, often, chronic use of aggression and violence. Additionally, theoretical and empirical research suggests the existence of two distinct patterns of aggression over time in youth: early onset and adolescent onset. However, it is not clear whether these patterns exist for subgroups defined by race and gender. Distinct aggression trajectories (i.e., patterns of aggression use over time) by race and gender would suggest differences across subgroups in the salience of particular risk factors and in the effects of timing of exposure to risk. Based on this framework, this study used semiparametric group-based modeling (SGM) to identify trajectories of self-reported aggression in a representative sample of 1,227 participants in Waves 1 to 7 of the National Youth Survey (NYS). Models were then fit separately to identify aggression trajectories for four sample subgroups: African American females (n = 76), African American males (n = 94), European American females (n = 509), and European American males (n = 488). Participants were between ages 11 and 17 (M = 13.8 years) at baseline and were followed over a 10-year period. The full-sample model identified 5 aggression trajectories. Of these, 3 were consistent with prior theory and research: low/stable (67.6%); adolescent onset (11.9%); and early onset/chronic (5.3%). Additionally, 2 trajectories identified in the full sample – young adult onset (11.8%) and early onset/desister (3.4%) – did not reflect prior conceptualizations of the onset and course of aggression, although similar trajectories have been identified in other studies using SGM methods. Analyses yielded different trajectory models across sample subgroups. For African American females and males, models identified low/stable and adolescent onset aggression trajectories. Aggression in the adolescent onset group decreased in later waves for African American females (similar to the full-sample model), but it remained high for African American males. Similar trajectories of aggression were found for European American females, and consistent with the full-sample model, a young adult onset trajectory was evident for this subgroup. Early onset trajectories were not evident for African American females and males, nor for European American females. The best model for European American males identified 3 aggression trajectories: low/stable, adolescent onset, and early onset/chronic. This model corresponded most closely to theoretical models describing the onset and course of aggression. An ecological developmental framework guides interpretation. Results suggest that the onset and course of aggression may follow different patterns across subgroups defined by race and gender. This, in turn suggests a need for further research on whether risk factors operate differentially across subgroups of youth, as well as a need for prevention and intervention efforts that reflect knowledge of such differences.