Abstract
Face images depicting the same individual can differ substantially from one another. Ecological variation in pose, expression, lighting, and other sources of appearance variability complicate the recognition and matching of unfamiliar faces, but acquired familiarity leads to the ability to cope with these challenges. Among the many ways that faces of the same individual can vary, some images are judged to be better likenesses of familiar individuals than others. Simply put, these images look more like the individual under consideration than others. But what does it mean for an image to be a better likeness than another? Does likeness entail typicality, or something else? We examined the relationship between the likeness of face images and the similarity of those images to identity averages using famous faces selected for reciprocal familiarity/unfamiliarity across US and UK participants. This allowed us to examine (1) How similarity was assessed relative to an identity norm as a function of familiarity and (2) How well likeness judgments were predicted by similarity to an identity norm. We found that familiarity did not affect similarity-to-prototype judgments much at all: US and UK observers largely agreed with one another with regard to these judgments for both sets of faces. We also found that though likeness judgments are correlated with similarity-to-prototype judgments made by both familiar and unfamiliar participants, this correlation was markedly smaller than the correlation between similarity judgments made by different participant groups. Finally, we replicated previous results demonstrating that increased familiarity with an individual tends to increase overall likeness ratings across all images, and that average face images tend to be rated as relatively poor likenesses. Considered together, these results imply that likeness is not the same as resemblance to an identity norm, raising important questions about the nature of identity representations in face space.