Causal effect of intergroup contact on exclusionary attitudes

There is generally conflict when members of different social groups, such as racial, ethnic, or religious groups, come in contact in the same geographic area. This phenomenon is commonly observed across a variety of settings. However, the cause of such conflict is poorly understood: Some theorists have argued that contact between groups is insufficient to cause conflict and that, under certain conditions contact may lead to improved intergroup relations. Although most theories of contact propose that repeated contact between individuals is important to the disposition of intergroup attitudes, experimenting on the effects of repeated contact has proven difficult. Here, I report a randomized controlled trial that assigns repeated intergroup contact between members of different ethnic groups. The contact results in exclusionary attitudes toward the outgroup.