Child development is the study or examination of mechanisms that operate during the biological and psychological process of growth of a child to adolescence, from dependency to increasing autonomy.
Pediatrics is the branch of medicine relating to the care of children. Age-related development terms are: Infant or baby (ages 0 - 1.5) , toddler (ages 1.5 - 2); child; preadolescence up to adolescence and puberty.
The optimal development of children is vital to society. Therefore the social, cognitive, emotional, and educational development of children is important to understand. Increased research and interest in this field has resulted in new theories and strategies, with specific regard to developmentally appropriate practice within the school system. Along with all of these developments there are also some theories that seek to describe a sequence of states that comprise child development.