The effect of familiarity on infants' social categorization capacity

Recent studies indicate that a preference for people from one's own race emerges early in development. Arguably, one potential process contributing to such a bias has to do with the increased discriminability of own- vs. other-race faces-a process commonly attributed to perceptual narrowing of unfamiliar groups' faces, and analogous to the conceptual homogenization of out-groups. The present studies addressed two implications of perceptual narrowing of other-race faces for infants' social categorization capacity. In Experiment 1, White 11-month-olds' (N = 81) looking time at a Black vs. White face was measured under three between-subjects conditions: a baseline “preference” (i.e., without familiarization), after familiarization to Black faces, or after familiarization to White faces. Compared to infants' a priori looking preferences as revealed in the baseline condition, only when familiarized to Black faces did infants look longer at the "not-familiarized-category" face at test. According to the standard categorization paradigm used, such longer looking time at the novel (i.e., "not-familiarized-category") exemplar at test, indicated that categorization of the familiarized faces had ensued. This is consistent with the idea that prior to their first birthday, infants already tend to represent own-race faces as individuals and other-race faces as a category. If this is the case, then infants might also be less likely to form subordinate categories within other-race than own-race categories. In Experiment 2, infants (N = 34) distinguished between an arbitrary (shirt-color) based sub-categories only when shirt-wearers were White, but not when they were Black. These findings confirm that perceptual narrowing of other-race faces blurs distinctions among members of unfamiliar categories. Consequently, infants: a) readily categorize other-race faces as being of the same kind, and b) find it hard to distinguish between their sub-categories.