Social Categories Alone Are Insufficient to Elicit an In-Group Advantage in Perceptions of Within-Person Variability

Within-person variability affects identity perception of other-race faces more than own-race faces; when participants sort images into piles representing different identities, they sort photographs of two other-race identities into more piles than two own-race identities. These results have been interpreted in terms of perceptual expertise, such that lack of experience with other-race faces leads to reduced ability to extract identity-relevant information across images. However, an alternative explanation is that sociocognitive factors (e.g., cognitive disregard for out-group faces) lead to differences in the number of perceived identities. Here, we examined whether social factors alone elicit an in-group advantage in perceptions of within-person variability. Caucasian participants sorted 40 photographs of two unfamiliar Caucasian identities (20 photographs/model) into piles based on the number of identities they believed were present. Half of the participants were told that the images were of students attending their university (in-group), whereas half were told that the images were of students attending a rival university (out-group). Participants sorted the photographs into a comparable number of identities for in- and out-group faces. This lack of an in-group advantage suggests that sociocognitive factors alone cannot account for differences in the number of perceived identities across faces from two categories.