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...

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...

We show how sanctioning is more effective in increasing cooperation between groups than within groups. We study this using a trust game among ethnically diverse subjects in Afghanistan. In the experiment, we manipulate i) sanctioning and ii) ethnic identity. We find that sanctioning increases...