This paper reports robust experimental evidence that humanization-in the form of individuating information about another's personal preferences-leads to decreased prosocial behavior toward in-group members. Previous research shows that this information increases prosocial behavior toward dehumanized out-group members. The consequences for in-group members, however, are less well understood. Using methods from social psychology and behavioral economics, four experiments show that individuating information decreases pro-social behavior toward in-group members in a variety of settings (charitable giving, altruistic punishment, and trust games). Moreover, this effect results from decreased reliance on group membership labels, and not from other potential explanations like the induction of new group identities. Understanding these effects sheds light on the motives behind intergroup conflict, which may not result from a difference in social perception (i.e., humanized in-groups and dehumanized out-groups), but rather from biases associated with group membership (i.e. in-group favoritism and out-group discrimination) that are eliminated by individuating information. Together, these results indicate that humanization carries a hidden cost for in-group members by disrupting group identities that would otherwise make them targets of altruistic actions.
Keywords: group bias; humanization; individuation; prosocial behavior.