Prosopagnosia: a defect in visual configural processing.

A patient with severe, lasting prosopagnosia could not get an immediate overview of a face sufficiently specific for successful identification. He also failed completely in tasks of visual closure despite adequate performances on numerous other tests of visual perception and memory. We conclude that prosopagnosia represents a loss of visual "configural processing"--a learned skill enabling immediate identification of individual members of a class without conscious visuospatial analysis or remembering. Prosopagnosia and agnosic alexia represent two distinct defects of configural processing: Alexics cannot identify items with distinctive features that are themselves identifiable. Prosopagnosics cannot identify objects whose critical distinguishing features have no independent identities.