This study examined the relationships among cooperative experiences, social interdependence predispositions, harm-intended aggression, victimization, and prosocial behaviors with 217 elementary school children from 3rd to 5th grade. Path analysis using LISREL indicates that cooperative experiences predicted cooperative predispositions, the absence of individualistic predispositions, and prosocial behaviors. Cooperative predisposition predicted prosocial behaviors and the absence of harm-intended aggression. Competitive predisposition predicted harm-intended aggression. These findings validate social interdependence theory and partially support theories related to social dominance. Providing frequent cooperative learning experiences may be an important tool to increase students' cooperativeness and thereby reduce the frequency of harm-intended aggression, increase the frequency of prosocial behaviors, and reduce students' individualistic predispositions.