Branch of psychology concerned with changes in cognitive, motivational, psychophysiological, and social functioning that occur throughout the human life span.
In the late 19th and early 20th centuries, developmental psychologists were concerned primarily with child psychology . In the 1950s they became interested in the relationship between child rearing and adult personality, as well as in examining adolescence in its own right. By the late 20th century they had become interested in all aspects of psychological development and change over the entire life span.