The interpretation of semantic category-specific deficits: What do they reveal about the organization of conceptual knowledge in the brain? Introduction

What does the existence of semantic category-specific deficits tell us about the organization of conceptual knowledge in the brain? Do these deficits reflect the existence of specialized mechanisms for the recognition and storage of specific semantic categories? Or do they merely reflect differences in the correlational structure of the properties that define concepts in different semantic domains? The received explanations of category-specific deficits have adopted a reductionist perspective, appealing to some or other non-categorical principle to explain the disorder. Some have appealed to the relative importance of the visual properties of objects in distinguishing among members of a semantic category; others have appealed to the relative strengths of correlations between visual and functional properties in different categories, However, there is also a proposal that semantic category-specific deficits reflect the fact that conceptual knowledge is organized into broad semantic domains, These proposals are briefly reviewed here.