Residential mobility reduces ingroup favouritism in prosocial behaviour

People sometimes prioritize helping ingroup members over outgroup members, but sometimes they do not. The current research investigated whether residential mobility, a socioecological factor, would reduce ingroup favouritism in prosocial behaviour. In three studies, we found evidence supporting the causal role of residential mobility in reducing ingroup favouritism in prosocial behaviour. First, we found that participants in the residentially stable condition had stronger intentions to help ingroups than outgroups whereas this tendency was eliminated in the residentially mobile condition (Study 1). We replicated these findings by examining participants' money allocation in a dictator game and their actual helping behaviour in an additional request (Study 2). Furthermore, we explored the underlying mechanisms of the effect of residential mobility on ingroup favouritism in prosocial behaviour (Study 3). We found that the differentiation component of individual identity (i.e., distinctiveness and uniqueness from other people) explained the relation between individuals' moving history and ingroup favouritism in prosocial behaviour (Study 3), in which frequent moves increased differentiation, which in turn reduced ingroup favouritism in prosocial behaviour. Taken together, these studies indicate that residential mobility is powerful in shaping people's behaviour toward ingroups and outgroups, which advances the understanding of intergroup processes from a socioecological approach. Copyright © 2018 Asian Association of Social Psychology and John Wiley & Sons Australia, Ltd.