The way in which we understand the concept of intelligence is rooted in metaphor and metonymy; for example, it is common to describe people as 'bright' or 'thick'. This book explores the motivation for some of the lexemes in this semantic field across the history of the English language, considering the range of cognitive mechanisms and cultural factors that can inform metaphorical and metonymical mappings. The book provides a much-needed diachronic approach to theories of metaphor and metonymy within cognitive semantics, building on the work of scholars such as Geeraerts and Sweetser. It argues that a diachronic approach offers a fresh perspective which can both complement and challenge current theories of metaphor and metonymy. It explores both cognitive and cultural issues relating to motivation, and takes account of established theories of semantic change alongside recent work in cognitive linguistics. It considers three of the concepts that have been important in the way intelligence is conceptualized diachronically: the senses, density, and animals, and it includes a detailed case study of these source concepts which provides a starting point for a wider discussion about the nature of mapping processes. (Publisher Book Description)