Abstract
Some studies have claimed that in face recognition holistic processing that deals with the spatial relation of each component and their global configuration predominates over other types of objects. In order to examine impaired processing of the visual system in prosopagnosia, this study investigated IM, a male with prosopagnosia but without object agnosia. In Experiment 1, we examined whether IM normally shows a face inversion effect in which recognition of inverted faces is impaired more than that of upright faces. His performance was severely impaired in the simultaneous unknown-face matching task. Moreover, IM showed inverted face inversion effect. He performed better at matching inverted faces than upright faces. In Experiment 2, he was asked to identify local or global letters of hierarchical stimuli with local letters hierarchically nested within global letters. In contrast to normal subjects, IM demonstrated “local precedence” in that his reaction time was faster for local than for global letters and his identification score was worse in the large visual angle condition (9°) compared with the small visual angle (3°). These results suggest that holistic processing is impaired in IM and that his prosopagnosic symptom may be caused by dysfunction of such visual processing system.
