This MIT-Harvard seminar focuses on the nature and development of human concepts by considering both infants' representations (e.g. of objects, actions, social partners) and children's inferential abilities. Discussion centers on research in human cognitive development, in relation to work in cognitive psychology, animal cognition, cognitive neuroscience, computational modeling, and philosophy. Questions include: Do humans possess innate abstract concepts of cause, agent, or belief? How do children learn new concepts, both independently and from others?