Social categorization processes often rely on observable, psychologically salient attributes, including ascribed characteristics (e.g., age, gender, nationality) and chosen affiliations (e.g., profession, ideology). These dimensions shape how individuals classify others into ingroups and outgroups, influencing perception, evaluation, and behavior. This study examined whether the strength of ingroup bias varies depending on whether group membership is endowed (inherent and unchosen) or agentic (self-selected). Using a within-subjects design, participants completed a perceptual matching task across two experiments: one comparing endowed groups (INDIA vs CHINA), the other comparing agentic groups (COGSCI vs GEOLOGY). Ingroup bias was measured through reaction times and accuracy. Results showed significantly stronger bias toward endowed groups, with a notable interaction between group type and task context. These findings suggest that the origin of group membership fundamentally shapes the intensity of social bias and offer new insights into the mechanisms underlying intergroup behavior and the dynamics of social categorization.