The authors have previously shown that intergroup interactions are dramatically more competitive than interindividual interactions and have termed this phenomenon a discontinuity effect. They believe that this effect is partly driven by group members' fear of being exploited by the out-group. Experiment 1 found that when subjects were allowed to select a single, safe alternative, a significant, albeit descriptively smaller competitive effect remained. Intergroup competiteness may also be driven by greed. Experiments 2 and 3 tested whether the group content is propitious for providing social support for totally self-interested acts. Trained role-players consistently suggested selecting either the cooperative or the competitive option in a prisoner's dilemma game; and groups received trial-by-trial feedback about the out-group's responding. The pattern of results is consistent with the assumption that, in the presence of a vulnerable opponent, group members tend to provide social support for immediate self-interest.