This collection of articles is completely and explicitly devoted to the new field of comparative developmental evolutionary psychology--that is, to studies of primate abilities based on frameworks drawn from developmental psychology and evolutionary biology. These frameworks include Piagetian and neo-Piagetian models as well as psycholinguistic ones. The articles in this collection--originating in Japan, Spain, Italy, France, Canada, and the United States--represent a variety of backgrounds in human and nonhuman primate research. The authors focus on such areas as the nature of culture, intelligence, language, and imitation; the differences among species in mental abilities and developmental patterns; and the evolution of life histories and of mental abilities and their neurological bases.