Facing up (or down)

Abstract

There is an active ongoing debate regarding the role of the fusiform region of the ventral occipitotemporal cortex. The recent increase in the use of fMRI has provided substance for this debate, leading to the hypothesis that an area in the fusiform gyrus (FG) is specialized for the perception of human faces. Nancy Kanwisher et al. reported some functional imaging data that seemed to demonstrate that there might indeed be a ‘face area’ in the FG (Ref. 1). The authors gave subjects four different perceptual tasks and recorded a significantly greater response in a region of the FG when the subjects were shown face stimuli compared with stimuli of common objects. The authors also found a stronger response when subjects were shown full front-view face photos than when shown front-view photos of houses. Three-quarter-view face photos elicited a greater response than photos of human hands, and intact faces a greater response than scrambled two-tone faces. Recently, Kanwisher et al. conducted an additional study2 involving both upright and inverted grayscale faces, and two-tone Mooney images (high-contrast black–white images of faces). The results strongly support the hypothesis of a ‘face area’ while demonstrating that the FG responds more strongly to inverted grayscale faces than to inverted two-tone Mooney images. Although a face-specific area in the FG is demonstrated by these studies, it is likely that there are other face-responsive areas yet to be discovered. Undoubtedly, functional imaging studies will continue to play an important role in the investigation of the visual processes underlying the recognition of human faces, and these in turn could help to guide the development of the next generation of models of brain function, incorporating face-recognition mechanisms.