The performance of groups has been thoroughly investigated in experimental economics, showing that groups are overall more rational deciders than individuals. However, superior group performance in economic experiments has primarily been shown for face-toface decision making, which has ceased to...

We study cooperation within and between groups in the laboratory, comparing treatments in which two groups have previously been (i) in conflict with one another, (ii) in conflict with a different group, or (iii) not previously exposed to conflict. We model conflict using an inter-group Tullock...