Theoretical BackgroundBruce and classical model of face recognition assumes parallel processing of facial identity and expression within functionally independent processing pathways. According to this model, faces are initially processed at a common stage of structural encoding, after which processing bifurcates into the analysis of different aspects of the face, such as facial identity, expression, and speech. The facial identity pathway is assumed to rely on viewpoint-and expression-independent descriptions of faces that are stored in face recognition units (FRUs), which contain the structural codes of familiar faces. In the functionally independent expression pathway, processing of facial expression occurs in parallel with that within the identity pathway. The assumption of independent identity and expression pathways has received support from behavioral, neurophysiological, and brain-imaging studies (e.g., Bruce, 1986;Bruce & Young, 1986;Ellis, Young, & Flude, 1990;Hasselmo, Rolls, & Baylis, 1989;Sergent, Ohta, Macdonald, & Zuck, 1994;Tranel, Damasio, & Damasio, 1988;Young, McWeeny, Hay, & Ellis, 1986;Young, Newcombe, & Haan, 1993). However, as we will outline in more detail below, more recent face perception studies have challenged, on various grounds, this assumption of parallel and independent processing pathways (see Calder & Young, 2005;Martens, Leuthold, & Schweinberger, 2010). The present psychophysiological study further investigates this issue by examining the influence of task-related and stimulus-related factors on the processing of facial identity and expression.Doubts about the parallel model of face perception and its assumption of independent identity and expression processing have originated from behavioral face perception studies using the Garner interference task (see Garner, 1976). In these studies, participants typically fail to ignore irrelevant variations in the identity or gender of faces when processing facial expression, but not vice versa (e.g., Atkinson, Tipples, Burt, & Young, 2005;Baudouin, Martin, Tiberghien, Verlut, & Franck, 2002; Schwein berger & Soukup, 1998). Schweinberger, Burton, and Kelly (1999) examined whether differences in the relative processing speed of the two face dimensions were responsible for this asymmetric Garner interference effect (see also Atkinson et al., 2005;Ganel & Goshen-Gottstein, 2004). To this end, they manipulated the time demands for facial identity and expression analysis, using faces that were morphed along happy-sad and familiar-unfamiliar dimensions. Critically, reaction time (RT) performance in the expression classification task was impeded by irrelevant variations in facial identity even for stimulus
505© 2010 The Psychonomic Society, Inc.On the temporal organization of facial identity and expression analysis: Inferences from event-related brain potentials
ULLA MARTENSUniversity of Osnabrück, Osnabrück, Germany
HARTMUT LEUTHOLDUniversity of Glasgow, Glasgow, Scotland
AND STEFAN R. SCHWEINBERGER
University of Jena, Jena, GermanyIn the pre...