Separable Mechanisms in Face Processing: Evidence from Hemispheric Specialization

Abstract

This article addresses three issues in face processing: First, is face processing primarily accomplished by the right hemisphere, or do both left- and right-hemisphere mechanisms play important roles? Second, are the mechanisms the same as those involved in general visual processing, or are they dedicated to face processing? Third, how can the mechanisms be characterized more precisely in terms of processes such as visual parsing? We explored these issues using the divided visual field methodology in four experiments. Experiments 1 and 2 provided evidence that both left- and right-hemisphere mechanisms are involved in face processing. In Experiment 1, a right-hemisphere advantage was found for both Same and Different trials when Same faces were identical and Different faces differed on all three internal facial features. Experiment 2 replicated the right-hemisphere advantage for Same trials but showed a left-hemisphere advantage for Different trials when one of three facial features differed between the target and the probe faces. Experiment 3 showed that the right-hemisphere advantage obtained with upright faces in Experiment 2 disappeared when the faces were inverted. This result suggests that there are right-hemisphere mechanisms specialized for processing upright faces, although it could not be determined whether these mechanisms are completely face-specific. Experiment 3 also provided evidence that the left-hemisphere mechanisms utilized in face processing tasks are general-purpose visual mechanisms not restricted to particular classes of visual stimuli. In Experiment 4, a left-hemisphere advantage was obtained when the task was to find one facial feature that was the same between the target and the probe faces. We suggest that left-hemisphere advantages shown in face processing are due to the parsing and analysis of the local elements of a face.

Quantifying interindividual variability and asymmetry of face-selective regions: A probabilistic functional atlas

“…In line with our observation, previous studies have reported the right-lateralization in face recognition. First, a bias for better retention and recognition of faces briefly presented to the left visual field is consistently observed in behavioral studies (Hillger and Koenig, 1991;Rhodes, 1985). Second, most, if not all, acquired prosopagnosics follow either bilateral or right unilateral occipitotemporal lesions (Bouvier and Engel, 2006;Landis et al, 1988).…”

Asymmetries of the human social brain in the visual, auditory and chemical modalities

“…Despite this the network is assumed to be largely bilateral, work on IOG, FFA and aIT (a role of STS in gaze selectivity will be dealt with later) has often evidenced a major involvement of the right hemisphere during identification and recognition of faces (Kanwisher et al 1997;Halgren et al 2000;Ishai et al 2000;Grill-Spector et al 2004;Rotshtein et al 2005;Kanwisher & Yovel 2006;Kriegeskorte et al 2007), and it has been suggested that the corresponding areas in the left hemisphere might subserve a more general process of object recognition, in a less face-selective fashion. Other evidence point instead to an asymmetrical subdivision of competences assigning a primacy for global analysis of faces to the right FG and for local or feature-based face analysis to the left FG (Rossion et al 2000;Harris & Aguirre 2008), a result suggested by previous behavioural and electroencephalographic studies of asymmetries in the processing of inverted faces and objects (Leehey et al 1978;Levine et al 1988;Hillger & Koenig 1991;Rossion et al 1999), and grounded on a more general theoretical framework that hypothesizes that the left hemisphere is specialized for processing high visual frequencies and the right hemisphere is specialized for processing low visual frequencies (Sergent 1983).…”

Hemispheric asymmetry in discriminating faces differing for featural or configural (second-order relations) aspects

“…For instance, using the divided visual field (DVF) methodology (in which stimuli are selectively presented in the left visual field (LVF) or right visual field (RVF), thus preferentially activating the contralateral hemisphere), Hillger and Koenig (1991) reported an RVF/LH advantage in a same-different judgment task for faces in which faces differed for a single feature (the same result was also reported by Parkin & Williamson, 1987). However, when faces differed for more than one feature, an LVF/RH advantage was reported (Hillger & Koenig, 1991). Other studies using the DVF paradigm to assess hemispheric specialization for holistic processing of faces have generally reported an LVF/RH advantage (Parkin & Williamson, 1987;Ramon & Rossion, 2012).…”