Jean Piaget was a Swiss developmental psychologist born in 1896 who is famous for his theories of child development. Piaget's theories focused on the cognitive and moral development of children as they interact with their biological environment. He was the first to put forth the theory that children develop in specific stages. Lawrence Kohlberg was an American developmental psychologist born in 1927 whose primary focus was on how children develop a sense of morality. The theories of Kohlberg are based on those of Piaget, although their theories and approaches differ as well.

Consider Piaget's theory of moral development. Explain that for Piaget moral development occurs in two distinct stages. Piaget theory is that young children believe that rules are dictated by either their parents or by God. Young children base their moral judgments on consequences rather than intentions. Clarify that for Piaget this way of thinking about morality changes for children around age 10, when they start to understand that morals are based on their own judgments and intentions. Explain that for Piaget the point is that children move from a concrete understanding of morality to a more abstract one, where they realize that rules are not absolute but are ways for humans to cooperate and get along.

Look at Kohlberg's theory of moral development. Notice that Kohlberg built upon Piaget's theory, but offers a more sophisticated understanding of childhood morality, in a six-stage model. Contrast this to Piaget's two-stage model. Notice that like Piaget, Kohlberg saw children's beginning understanding of morality as having to do with rules and consequences. Notice too that Kohlberg believed that children struggle, over time, with issues connected to morality such as individual rights, relationships, social order and universality. Note that Kohlberg's theory offers more detail and a deeper understanding of human development of morality than Piaget's.

Compare the work of Kohlberg and Piaget as stage theorists. Piaget was the first psychologist to postulate a stage theory of cognitive development. For Piaget, children develop intellectually in a hierarchical manner, in four specific stages ranging from infancy to adolescents. Contrast this to Kohlberg's five stages of moral development. These are also hierarchical but unlike Piaget do not specify age ranges. Note that Kohlberg's stages also allow for development of morality throughout the life span, not just until adolescence. Notice that for Kohlberg stages of moral development stem from socialization. That is, interactions with parents, teachers and peers lead to the individual's understanding of what is morally right and wrong. Contrast this with Piaget's theory of cognitive development in which intelligence develops in conjunction with biological development.