Education at Harvard University. Even though it was considered unusual in his era, he decided to study the topic of moral judgment, extending Jean Piaget's account of children's moral development from twentyfive years earlier. In his 1958 dissertation, Kohlberg wrote what are now known as Kohlberg's stages of moral development. Lawrence Kohlberg's stages of moral development constitute an adaptation of a psychological theory originally conceived by the Swiss psychologist Jean Piaget. Kohlberg began work on this topic while a psychology graduate student at the University of Chicago in
1958, and expanded and developed this theory throughout his life. The theory holds that moral reasoning, the basis for ethical behavior, has six identifiable developmental stages, each more adequate at responding to moral dilemmas than its predecessor.
Kohlberg followed the development of moral judgment far beyond the ages studied earlier by
Piaget, who also claimed that logic and morality develop through constructive stages. Expanding on Piaget's work, Kohlberg determined that the process of moral development was principally concerned with justice, and that it continued throughout the individual's lifetime, a notion that spawned dialogue on the philosophical implications of such research. The six stages of moral development are grouped into three levels: preconventional morality, conventional morality, and postconventional morality. For his studies, Kohlberg relied on stories such as the Heinz dilemma, and was interested in how individuals would justify their actions if placed in similar moral dilemmas. He then analyzed the form of moral reasoning displayed,