Lawrence Kohlberg (October 25, 1927 – January 19, 1987) was a Jewish American psychologist born in Bronxville, New York, who served as a professor at the University of Chicago, as well as Harvard University. Having specialized in research on moral education and reasoning, he is best known for his theory of stages of moral development. A close follower of Jean Piaget's theory of cognitive development, Kohlberg's work reflected and extended his predecessor's ideas, at the same time creating a new field within psychology: "moral development". Scholars such as Elliot Turiel and James Rest have responded to Kohlberg's work with their own significant contributions. In an empirical study by Haggbloom et al. using six criteria, such as citations and recognition, Kohlberg was found to be the 30th most eminent psychologist of the 20th century.^[1]

stages of moral development

In his 1958 dissertation, Kohlberg wrote what are now known as Kohlberg's stages of moral development.^[2] These stages are planes of moral adequacy conceived to explain the development of moral reasoning. Created while studying psychology at the University of Chicago, the theory was inspired by the work of Jean Piaget and a fascination with children's reactions to moral dilemmas.^[3] Kohlberg proposed a form of “Socratic” moral education and reaffirmed Dewey’s idea that development should be the aim of education. He also outlined how educators can influence moral development without indoctrination and how public school can be engaged in moral education consistent with the Constitution.^[4]

His theory holds that moral reasoning,which is the basis for ethical behavior, has six identifiable developmental constructive stages - each more adequate at responding to moral dilemmas than the last.^[5] In studying these, Kohlberg followed the development of moral judgment that is far beyond the ages originally studied earlier by Piaget,^[6] who also claimed that logic and morality develop through constructive stages.^[5] Expanding considerably upon this groundwork, it was determined that the process of moral development was principally concerned with justice and that its development continued throughout the life span,^[2] even spawning dialogue of philosophical implications of such research.^[7][8]

Kohlberg studied moral reasoning by presenting subjects with moral dilemmas. He would then categorize and classify the reasoning used in the responses, into one of six distinct stages, grouped into three levels: pre-conventional, conventional and post-conventional.^[9][10][11] Each level contains two stages. These stages heavily influenced others and have been utilized by others like James Rest in making the Defining Issues Test in 1979.^[12]