¶ … Youth Jean Piaget's theory of child development dates back to the 1920s, although he became more prominent in the 1950s. Like the Freudians, he posited that children underwent certain stages of moral and cognitive development, although these were not so heavily based on sexuality and gratification of the basic drives and instincts of the id. Rather he maintained the infants and small children passed through a stage of gaining basic control over sensorimotor and bodily functions, eventually developing concrete and finally abstract thought by the end of adolescence. He also recognized that cognitive development and morality were closely related, as did Erik Erikson and the other ego psychologists. Piaget claimed that children should develop ethics of reciprocity and cooperation by the age of ten or eleven, at the same time they became aware of abstract and scientific thought. Erikson in particular deemphasized the early Freudian concern with oral, anal, phallic and genital stages in favor of a model that emphasized the development of children into autonomous, fully functioning individuals, free from neurotic shame and guilt imposed by parents during toilet training and early sexual experimentation. He also argued that schizophrenia, neurosis, hysteria and obsessive-compulsive disorders all had their roots in early children, starting from the time when infants first learned that they could trust their mothers during feeding.

Piaget was certainly ahead of his time in studying the mental and moral development of infants and children, at a time when such research was uncommon. Researchers today would not "know even a fraction of what they know about intellectual development without Piaget's groundbreaking work" (Sigelman and Reder, 2012, p, 232). He was the first to realize that infants were very active in their own cognitive development and that children had quite different...

Adolescents were more capable of abstract and scientific thought, but also distracted by their own form of sexual and emotional self-centeredness. His theories have been validated across all cultures, along with the basic stages of cognitive development from sensorimotor in infants to preoperational in young children, concrete operations in older children and formal operations in adolescence and young adulthood. Piaget probably underestimated the cognitive abilities of infants and young children, though, and was too quick to assume that they lacked competence in all areas if they were unable to pass his tests. He did not realize that infants developed the concept of object permanence gradually, from the ages of four to nine months rather than all at once. Cognitive development in general is "domain specific" and "growth in one domain may proceed much faster in one domain than another" (Sigelman and Reder, p. 233).
In addition to developing reasoning powers and abstract thought, older children and adolescents should also begin to understand needs beyond their own egos, such as cooperation with others in society. They will gradually move beyond the stage of regarding morality and simply a set of concrete and unchanging rules and laws handed down by higher authorities, although in reality of course many people never do. Instead, they will increasingly realize that others will not have the same concepts of morality and that right and wrong may vary depending on the social context. They will also increasingly come to recognize the concept of fairness and reciprocity, so that moral decisions benefit all parties concerned, and by adolescence will learn to look at life from the point-of-view of others and to consider their interests. In this sense, they begin to…