When and why are social categories overused relative to individuating information? A Bayesian approach to identifying biases in impression formation processes.

When making inferences about others, people often need to integrate multiple types of information, including the person's social categories (e.g., occupation) as well as other "individuating" information (e.g., their behaviors). The current work reexamines this integration process to understand when and why it produces biases involving overreliance on category information. We identify two key challenges in identifying such biases, and develop a novel Bayesian modeling approach to overcome them. As a first step in applying this approach, the current work examined a set of novel predictions based on viewing the continuum model of impression formation in light of this Bayesian approach. Specifically, a series of six studies tested whether occupation categories might be overused in general, or especially in conditions thought to reduce effortful processing (i.e., greater cognitive load or information consistency). Results showed no evidence of category overuse, nor of shifts in this direction, in any of these conditions (though some ambiguity remained about the load manipulation's effectiveness). This provides initial evidence against the idea that intrinsic differences in how these categories are processed or represented will lead to their overuse. A seventh study provided the first direct evidence of a case where categories were overused: when contextual factors (i.e., background goals) made them the category especially relevant, while processing resources were limited. More broadly, the current work developed the theoretical and methodological foundations for identifying category overuse that stems from biased inference processes and demonstrated the power of this approach for understanding when and why such biases occur. (PsycInfo Database Record (c) 2026 APA, all rights reserved).