Lawrence Kohlberg was an American psychologist best known for his theory of stages of moral development. He was born in 1927 in New York and earned his bachelor's degree from the University of Chicago in just one year. Kohlberg's stages of moral development propose that morality develops through six stages grouped into three levels - pre-conventional, conventional, and post-conventional. Kohlberg studied moral reasoning by presenting subjects with dilemmas and analyzing their responses. His influential theory holds that higher stages allow for greater decision making abilities. Kohlberg taught at various universities and conducted research until his death by suicide in 1987 in Massachusetts.