Social categorization modulates own-age bias in face recognition and ERP correlates of face processing

The aim of the present study was to further understanding of how social categorization influences face recognition. According to the categorization-individuation model, face recognition can either be biased toward categorization or individuation. We hypothesized that the face recognition bias associated with a social category (e.g., the own-age bias) would be larger when faces were initially categorized according to that category. To examine this hypothesis, young adults (N = 63) completed a face recognition task after either making age or sex judgments while encoding child and adult faces. Young adults showed the own-age and own-sex biases in face recognition. Consistent with our hypothesis, the magnitude of the own-age bias in face recognition was larger when individuals made age, rather than sex, judgments at encoding. To probe the mechanisms underlying this effect, we examined ERP responses to child and adult faces across the social categorization conditions. Neither the P1 nor the N170 ERP components were modulated by the social categorization task or the social category membership of the face. However, the P2, which is associated with second-order configural processing, was larger to adult faces than child faces only in the age categorization condition. The N250, which is associated with individuation, was larger (i.e., more negative) to adult than child faces and during age categorization than sex categorization. These results are interpreted within the context of the categorization-individuation model and current research on biases in face recognition.