Chapter 6: Physical Development

Welcome to the story of development from infancy through adolescence. Did you ever wonder how babies grow from tiny, helpless infants into well-developed and independent adults? It doesn’t happen overnight, but the process begins right from day one. We’ll begin this module by reviewing the rapid physical development that occurs during infancy and early childhood, the changes of middle childhood, and finally, the maturation during adolescence. In some ways, the changes in adolescence are more dramatic than those that occur in infancy—unlike infants, adolescents are aware of the changes that are taking place and of what the changes mean. In this section, we will learn about the pubertal changes in body size, proportions, and sexual maturity, as well as the social and emotional attitudes and reactions toward puberty. Since nutrition and health are so important throughout childhood and adolescence for lifetime development, and the consequence of neglect can be severe, we will consider some of the influences on early physical growth, particularly the importance of nutrition and some of the health concerns during adolescence, including eating disorders.

The obvious physical changes are accompanied by changes in the brain. While we may not observe the actual brain changing, we can see the effects of the brain changes in the way that children sense, move, sleep, play, and learn. We will explore how infants’ senses develop and how sensory systems like hearing and vision operate, and how infants take in information through their senses and transform it into meaningful information. Infants are also born with motor abilities. At birth, infants are equipped with a number of reflexes, which are involuntary movements in response to stimulation. We will explore how these innate reflexes are eventually modified through experiences to become voluntary movements and the basis for motor development as skills emerge throughout childhood.