Abstract: | Groups and individuals were compared in two experiments. In the first, two same-sex individuals or two same-sex dyads played 10 trials of a Prisoner's Dilemma matrix game (PDG) for money. Play between individuals was more cooperative and less competitive than play between groups. In the second experiment subjects played 10 trials of either PDG or mutual-fate-control (MFC) matrices. For the MFC matrix the competitive choice, which reduces the opponent's outcomes, but has no effect on own outcomes, reflects a desire to increase one's relative advantage over the opponent. Although cooperation was greater for MFC, for both PDG and MFC matrices groups were more competitive and less cooperative than individuals. A large component of the groups-individuals effect is attributed to the greater desire of groups to “win” or avoid “losing” to the opponent, regardless of their absolute outcomes. |