Dissociations of visual recognition in a developmental agnosic: evidence for separate developmental processes.

We report the results of tests investigating the recognition of faces, places, and objects in a developmental agnosic, because dissociations of visual recognition in developmental agnosics provide insight into the separable procedures performing recognition and the developmental origins of these procedures. TA is a software engineer in his early 40s with developmental prosopagnosia. He performs normally on tests of low-level vision, and he names objects at the basic level normally. In order to compare his recognition abilities for different classes, we have presented him with a famous landmarks test, a famous faces test, and old/new discriminations involving unfamiliar faces, houses, natural landscapes, cars, horses, guns, sunglasses, and tools. He was impaired on the face recognition tests, but performed normally on the place recognition tests. He also showed severe impairments with horses and cars, borderline impairments with guns and sunglasses, and normal performance with tools. These results indicate that the developmental processes that assemble the procedures used for face recognition and certain types of object recognition are separate from those processes that produce the procedures used for place recognition.