Perceiving expatriate coworkers as foreigners encourages aid: social categorization and procedural justice together improve intergroup cooperation and dual identity.

We propose that social categorization can encourage particular forms of intergroup cooperation because it differentiates a group in need from a group that can give aid. Moreover, social categorization is most likely to occur when individuals perceive procedural justice (i.e., fair treatment) from authorities in a superordinate group that includes the individuals' subgroup. Two field studies investigating relations between local and foreign coworkers tested not only this prediction, but also whether high social categorization and procedural justice would yield a dual identity, in which group members identify simultaneously with their social category and the superordinate group. Both studies supported our predictions: Local employees engaged a dual identity and offered knowledge to aid a foreign coworker's adjustment more often when local-foreign categorization and procedural justice from organizational authorities were high than when these variables were low. These discoveries point to controllable mechanisms that enable intergroup cooperation, and our findings have important implications for intergroup aid, expatriate adjustment, immigration, and multiculturalism.