The minimal group effect, in which people prefer ingroup members to outgroup members even when group membership is trivially constructed, has been studied extensively in psychological science. Despite a large body of literature on this phenomenon, concerns persist regarding previous developmental research populations that are small and lack racial/ethnic diversity. In addition, it remains unclear what role holding membership within and interacting with specific racial/ethnic groups plays in the development of children's group attitudes. Using a collaborative multi-site study approach, we measured 4- to 6-year-old children's (N = 716 across five regions in the United States
47.1% girls
40.5% White, 13.3% Black, 12.6% Asian, 24.6% Latine, 9.2% multiracial) minimal group attitudes and preference for real-world racial/ethnic ingroups and outgroups. We found that, as a whole, the minimal group effect was observed in the total sample, and no significant differences were found between racial/ethnic groups
yet exploratory analyses revealed that the minimal group effect was most strongly displayed among older children compared with younger children and, when considered separately, was more clearly present in some racial/ethnic groups (White) but not so in others (Black). In addition, there was no relationship between children's minimal group attitudes and racial group preferences, suggesting that factors other than ingroup/outgroup thinking may influence young children's racial bias. Taken together, results highlight the continued need for large and racially diverse samples to inform and test the generalizability of existing influential psychological theories.