Deficits in sensitivity to spacing after early visual deprivation in humans : a comparison of human faces, monkey faces, and houses

Early visual deprivation caused by bilateral congenital cataracts produces deficits in discriminating faces that differ in the spacing of features, but not in feature shape (Le Grand et al. [2001] Nature 410: 810). We investigated whether these deficits are specific to human faces by testing patients' ability to discriminate between stimuli differing only in feature spacing in human and monkey faces (Experiment 1) and in houses (Experiment 2). Patients, as a group, showed deficits on only one task: they had lower accuracy than normal in discriminating feature spacing in human faces. In contrast, they were normal in discriminating feature spacing in monkey faces and in houses. The results suggest that early visual experience is necessary to set up (or preserve) the neural architecture used for processing human faces, but not for processing objects in general.