Faces and non-face objects of expertise recruit overlapping visual processes indexed by the N170

Rossion, B.1,3, Curran, T.2, Collins, D.2, Kung, C.-C.3, Goffaux, V.1, and Tarr, M. J.3
1Unité de Neurosciences Cognitives and Laboratoire de Neurophysiologie, University of Louvain, Belgium; 2Department of Psychology, University of Colorado at Boulder; 3Department of Cognitive and Linguistic Science, Brown University
E-mail: bruno.rossion@psp.ucl.ac.be

Previous ERP studies have shown that human faces lead to a larger occipito-temporal visual component, the N170, compared to other object categories (e.g. Rossion et al., 2000). This N170 difference has been interpreted as evidence for the occurrence of early face-specific processes (Bentin et al., 1996). However, visual expertise with non-face objects increases the N170 (e.g. Tanaka & Curran, 2001), suggesting that faces and objects of expertise share visual processes taking place at this processing stage. Here we used a competition paradigm in ERPs to provide further evidence in favor of the latter hypothesis. In two studies, the N170 in response to lateralized faces was recorded while subjects were processing a non-face object presented centrally. Subjects simply reported the side of the face presentation. In the first study, the N170 in response to faces was substantially decreased when preceded by a novel object (Greeble) remaining on the screen. This decrease of the face-evoked N170 was observed only after subjects had been trained extensively with the object category. In the second study, a substantial reduction of the face-evoked N170 was found in car experts processing pictures of cars. The effect was not found for car novices, and was not due to low-level visual features of car pictures. Together, these results show that faces and non-face objects in a domain of expertise compete for overlapping visual processes reflected by the N170. More generally, they indicate that early face categorization processes can be tuned by visual experience in adults.