Lawrence Kohlberg (/ˈkoʊlbərɡ/; October 25, 1927 – January 19, 1987) was an American psychologist best known for his theory of stages of moral development. He served as a professor in the Psychology Department at the University of Chicago and at the Graduate School of 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 twenty-five years earlier.