Research on the evolution of higher intelligence rarely combines data from fields as diverse as paleontology and psychology. In this volume we seek to do just that, synthesizing the approaches of hominoid cognition, psychology, language studies, ecology, evolution, paleoecology and systematics toward an understanding of great ape intelligence. Leading scholars from all these fields have been asked to evaluate the manner in which each of their topics of research inform our understanding of the evolution of intelligence in great apes and humans. The ideas thus assembled represent a comprehensive survey of the various causes and consequences of cognitive evolution in great apes. The Evolution of Thought will therefore be an essential reference for graduate students and researchers in evolutionary psychology, paleoanthropology and primatology.