Developmental psychology, also called human development, is the emotional study of how a person changes psychologically (mind and behavior) as they get older. Developmental psychologists first studied infants and children, and later they also studied teenagers (or adolescents) and adults. Developmental psychology studies human change in a lot of areas, including motor skills (and other processes that are both physical and psychological), problem solving abilities, understanding of concepts, learning language, moral understanding, and identity.