The Effect of Personal Familiarity on the Speed of Face Recognition

The Effect of Personal Familiarity on the Speed of Face Recognition Benjamin Balas (bjbalas@mit.edu) David Cox (davidcox@mit.edu) Department of Brain and Cognitive Sciences Massachusetts Institute of Technology Cambridge, MA 02139 Erin Conwell (econwell@brown.edu) Department of Cognitive and Linguistic Sciences Brown University Providence, RI 02912 has led to the powerful, early idea that various face recognition tasks might be executed by parallel, non- overlapping “modules” (Bruce & Young, 1986). Since face familiarity ostensibly depends on the identity of a face, it has been suggested that under such a model, face familiarity should not affect other tasks, such as gender judgments, because “identity” and “gender” would be processed by separate, non-interacting modules. Along these lines, there are some results that indicate familiarity does not appear to affect gender recognition (Bruce, 1986) or expression classification (Young, McWeeny, Hay, & Ellis, 1986). More recently, substantial evidence has emerged that familiarity does influence other “orthogonal” face judgments. Using images that were parametrically morphed along a continuum between trained (“familiar”) and untrained (“unfamiliar”) faces, Rossion demonstrated significantly faster response times (RTs) for sex classification of the familiar stimuli compared to the unfamiliar images (Rossion, 2002). Likewise, other researchers have pointed out cases where it appears that there are interactions between the familiarity of a face and the processing of race (Bruyer, Leclere, & Quinet, 2004), expression (Gallegos & Tranel, 2005; Kaufmann & Schweinberger, 2004), and even speech (Walker, Bruce, & O'Malley, 1995). Taken together, these studies suggest that experience with faces might exert a strong influence on tasks beyond those that are explicitly related to identity. In the present study, we sought to extend what is known about facial familiarity in three simple delayed-match-to- sample tasks in which subjects were required to match faces on the basis of orientation (upright or inverted), gender, or identity. We assess the extent to which familiarity with a face lowers the response time for accurate classification across our three judgments. There are several reasons why we believe this experiment fills important gaps in our understanding of familiar face processing. First, the use of a matching task minimizes the memory and training requirements necessary to carry out our three recognition tasks. Also, regardless of whether the subject is matching a face according to gender, identity, orientation (or any other attribute we might choose), the nature of the response (a Abstract While previous studies have explored the effects of familiarity on various kinds of visual face judgments, the role of familiarity in face processing is not fully understood. Here, we examine the effect of real-world personal familiarity in three simple delayed-match-to-sample tasks in which subjects were required to match faces on the basis of orientation (upright v. inverted), gender and identity. We find that subjects had a significant speed advantage with familiar faces in all three tasks, with the advantage for familiarity in the orientation case being markedly smaller than the other conditions. This indicates that real-world experience with a face exerts a powerful influence on face processing in tasks where identity information is irrelevant, even in tasks that could in principle be solved via low-level cues. These results underscore the importance of experience in shaping visual recognition processes. Introduction The human visual system effortlessly and automatically extracts a wealth of information from face stimuli, including identity, gender, expression, race, age, and a host of other properties. For the most part, the ability to extract such information from a given face does not require extensive exposure to that particular face, and judgments of properties such as gender or race are performed with high accuracy even on completely novel faces. Even so, humans tend to encounter a relatively small number of faces repeatedly, and it is not surprising that these familiar faces may enjoy some processing advantages relative to unfamiliar faces. (Ge, Luo, Nishimuira, & Lee, 2003; O'Donnell & Bruce, 2001; Bruce, Henderson, Newman, & Burton, 2001; Hancock, Bruce, & Burton, 2000). However, it is not clear a priori that all face judgments should necessarily benefit from familiarity, nor is there any reason to believe that various kinds of judgment should benefit equally from familiarity. Variation in the advantage conferred by familiarity across tasks could provide important clues to the nature of face representations. The conceptual orthogonality of many face judgments (e.g. the expression of a face is independent of its gender)