Walsh & Hoyt: The Specificity of the Prosopagnostic Defect

Can the prosopagnosic defect be truly specific for faces only? This point is of great relevance to debates about high-level visual processing, particularly as to whether its organization is highly modular for different stimuli. Most patients with prosopagnosia can identify objects at some basic level or category, unlike patients with severe generalized visual agnosia. However, some cannot identify subtypes (""subordinate categories"") such as types of cars, food, or coins, or specific individuals (""exemplars"") such as buildings, handwriting, or personal clothing. On the other hand, other patients reportedly can identify personal belongings, individual animals, specific places, cars, flowers, vegetables, and different eyeglasses. Thus, in some patients the defect appears to be highly specific for faces, in support of a modular account. However, a recent review with detailed measures of reaction time and signal detection parameters in two patients with prosopagnosia has argued that deficits in non-face processing are present even when accuracy rates suggest otherwise.