The purpose of this work was to investigate the way in which boys, ages 6, 8, and 10 years, who are behaviorally disturbed, understand motives behind human behavior, compared to normally functioning peers. Four tasks were administered that differed in surface features but that shared an underlying conceptual structure. A structural analysis of response protocols was undertaken to assess the level of cognitive complexity of their productions. Age-appropriate performance required varying degrees of intentional understanding (i.e., the reciprocal causal relations between action and mental states such as feelings and desires). The results of this analysis supported our predictions that behaviorally disturbed children use developmentally naive reasoning in the domain of conflict resolution, compared with their normal peers. Additionally, a thematic analysis of the content of responses was performed. The results of this analysis showed that the two groups' reasoning also differed qualitatively, in that the aggressive boys showed greater evidence of socially maladaptive thought, whereas the comparison group's performance was largely adaptive. We propose that early-formed primitive defense mechanisms may interfere with the aggressive group's construction of prosocial mental models of the social world. The results suggest that this line of research, which integrates developmental and psychoanalytic theory, has the potential to offer insight into the mechanisms underlying behavioral aggression.