The formation of a system of underlying assumptions about standards and principles that govern moral decisions.

Moral development involves the formation of a system of values on which to base decisions concerning "right" and "wrong, " or "good" and "bad." Values are underlying assumptions about standards that govern moral decisions.

Although morality has been a topic of discussion since the beginning of human civilization, the scientific study of moral development did not begin in earnest until the late 1950s. Lawrence Kohlberg (1927-1987), an American psychologist building upon Jean Piaget's work in cognitive reasoning, posited six stages of moral development in his 1958 doctoral thesis. Since that time, morality and moral development have become acceptable subjects of scientific research. Prior to Kohlberg's work, the prevailing positivist view claimed that science should be "value-free"—that morality had no place in scientific studies. By choosing to study moral development scientifically...