Category Utilization Among Perceptually Ambiguous Groups: The Roles of Base Rates and Perceived Stigma

People often show a response bias when categorizing others as members of perceptually ambiguous groups. Specifically, perceivers are more likely to categorize individuals into a nonstigmatized group (e.g., straight) than a stigmatized group (e.g., gay). Previous work suggests that both perceived base rates and benevolent reasoning underlie this bias. However, no research has simultaneously examined both accounts to investigate their relative and combined effects. Across four studies, participants categorized unknown targets based solely on visual information. Studies 1A-2 used fictitious groups to manipulate perceived stigma and population base rates. These studies showed that base rates consistently biased categorizations, while group stigma did not. Study 3 conceptually replicated these effects with a group stigmatized in the real world. These findings suggest that population base rates play a robust role in category utilization for perceptually ambiguous groups.