Concepts and Categories: Memory, Meaning, and Metaphysics

The psychological study of concepts has two main goals: explaining how people's knowledge of categories such as tables or cats enables them to classify or recognize members of those categories, and explaining how knowledge of word meanings (e.g., the meaning of table and cat) enables people to make inferences and to compute the meanings of phrases and sentences. We review current theories and data relevant to these two functions of concepts, including recent insights from cognitive neuropsychology. Both kinds of theories have evolved in ways that suggest that people make use of mental representations at several levels of complexity, from sparse, atomic concepts to complex, knowledge-intensive ones. We examine the implications of this variety for issues including psychological essentialism and domain specificity.