The first-member heuristic: Group members labeled "first" influence judgment and treatment of groups.

People often make judgments about a group (e.g., immigrants from a specific country) based on information about a single group member. Seven studies ( = 1,929) tested the hypothesis that people will expect the performance of an arbitrarily ordered group to match that of the group member in the first position of a sequence more closely than that of group members in other positions. This greater perceived diagnosticity of the first member will in turn affect how people treat the group. This pattern of judgment and treatment of groups, labeled the "first-member heuristic," generalized across various performance contexts (e.g., gymnastic routine, relay race, and job performance), and regardless of whether the focal member performed poorly or well (Studies 1-3). Consistent with the notion that first members are deemed most informative, participants were more likely to turn to the member in the first (vs. other) position to learn about the group (Study 4). Further, through their disproportionate influence on the expected performance of other group members, first members' performances also influenced participants' support for policies that would benefit or hurt a group (Study 5) and their likelihood to join a group (Study 6). Finally, perceived group homogeneity moderated the first-member heuristic, such that it attenuated for nonhomogeneous groups (Study 7). (PsycINFO Database Record (c) 2020 APA, all rights reserved).