Group membership biases children's evaluation of evidence

People form beliefs not only as individual agents, but as members of social groups. Here, we investigate how group membership influences belief formation and revision in childhood. Across three studies (N = 262), 4-6-year-old children either joined one of two groups or neither group, then evaluated evidence to arrive at a conclusion. Children who belonged to a group were more convinced by evidence that supported their ingroup's belief (Study 1 & 2) and were less convinced by evidence that opposed their ingroup's belief (Study 3), leading them to hold inaccurate group beliefs. Children who did not belong to a group rationally evaluated the available evidence and arrived at accurate conclusions. These results suggest that group membership modulates children's evidentiary standards.