Evolutionary psychology is a new and rapidly expanding area of study. All psychology is in a sense 'evolutionary psychology' since, if we disregard Creationism, the only forces which could have shaped the human mind are evolutionary forces. However, psychologists have traditionally regarded this fact as irrelevant to the practical problems of formulating and testing psychological theories. This book contains chapters by some of the leading figures in this new field. The latest data are presented on evolutionary theories in perception, information, various aspects of social behaviour, language, learning and aggression. A common theme running through the printed discussions in this book is the important problem of how we can develop and test rigorous characterizations of evolved mental adaptations.