Developmental psychologists study the physical and mental development of human beings from the time of conception till old age.

Child psychology is a part of the developmental psychology, as it studies the growth and development of the child from conception till adolescence. Studying the child is helpful for understanding adult behaviors, as most of the adult personality and behaviors are the results of childhood experiences. Moreover, the development is much faster in the early years than later years of life. Both the developmental and child psychologists have similar interests except that child psychologists confine themselves to the in-depth study of the behaviors during the early part of human life.

The developmental psychologists study the cognitive, emotional, and motivational development during the entire life span of the individual. It covers all the life-span stages such as infancy, childhood, adolescence, adulthood, and old age. This field focuses on the developmental changes in perception, learning, thinking, emotion, language skills, personality, and social relationships.

For each stage of development, it identifies the needs and the challenges faced by the individual. It also studies the developmental pattern of special groups of people. Child psychology studies the same basic psychological processes in children emphasizing the role of heredity and environment in shaping behaviors in the early years of life. Child psychologists help parents and teachers in providing guidance for children development and education.