Psychological Development is the scientific study of how and why human beings change over the course of their life. Originally concerned with infants and children, the field has expanded to include adolescence, adult development, aging, and the entire lifespan. This field examines change across three major dimensions: physical development, cognitive development, and socioemotional development. Within these three dimensions are a broad range of topics including motor skills, executive functions, moral understanding, language acquisition, social change, personality, emotional development, self-concept and identity formation. In this book the area of discussion and analysis has been delimited to physiological and psychological areas so as to give a deeper treatment to the subject. It is hoped that the book will find a wider acceptance among teachers and researchers. The book is of interest to the researchers and students of psychology, sociology, child development, family studies and professionals interested in related fields.