Category specific recognition impairments: a review of important case studies and influential theories

Abstract

Patients with category specific recognition impairments for living and non living things have played a crucial role in developing current theories of semantic memory and object recognition. This paper reviews a number of the classic cases and discusses the theories that have been developed to account for these impairments. The first reports of patients with category specific recognition impairments for living and non living things were documented by Nielsen, who argued that they arose because living and non living things were stored in functionally and anatomically separate systems. Although this hypothesishas been reiterated in some recent papers, the most widespread view hasbeen that they emerge because living andnon living thingshave contrasting processing demands. The latter accounts include those which stress the relative importance of: the 'weighting of sensory and functional features associated with living and non living things; the role of structural similarity between objects; the role of direct experience with objects; direct links between perceptual and functional features; and category structure. These theories are reviewed before outlining our own view on why category specific recognition impairments emerge following brain damage.