Abstract
Experiments involving brief lateral presentations of faces demonstrate that right hemisphere mechanisms used for face processing tend to be superior to those in the left hemisphere, and this behavioral effect is consistent with neuroimaging, neurophysiological, neuropsychological, and developmental evidence showing right hemispheric superiority. Developmental prosopagnosia (DP) is a condition defined by severe face recognition deficits due to a failure to develop the mechanisms necessary for face recognition. To identify whether one hemisphere or both contain the defective mechanisms, we tested a group of right-handed DPs with a sequential matching task and compared their performance to right-handed controls. A frontal view was presented centrally for 2000 ms, and after a brief ISI, a 1/3 profile was presented for 180 ms. Whereas nearly every control showed left visual field superiority, the majority of the DPs showed right visual field superiority. Of the DPs with a reversed laterality bias, most scored in the normal range in the right visual field. These results indicate that DP often results from deficits to right hemisphere mechanisms and that mechanisms used for face recognition in the different hemispheres depend on different developmental processes.