Effects of minimal grouping on implicit prejudice, infrahumanization, and neural processing despite orthogonal social categorizations

Racial prejudice is a pervasive and pernicious form of intergroup bias. However, a mounting number of studies show that recategorization—even into minimal groups—can overcome the typical consequences of racial and other group classifications. We tested the effects of minimal grouping on implicit prejudice and infrahumanization using a paradigm in which race was orthogonal to group membership. This allowed us to examine whether knowledge of group membership overrides obvious category differences. We found that participants infrahumanized and showed implicit bias toward the minimal outgroup, despite the cross-cutting presence of race, and in fact did not show any of the usual implicit racial bias. In addition, event-related potentials (ERPs) showed an early race effect followed by distinct reactions on the basis of group as processing continued. This is evidence that arbitrary social classifications can engender ingroup preference even in the presence of orthogonal, visually salient categorizations.