Lawrence Kohlberg (1927–1987) was an American developmental psychologist. Kohlberg’s research focused mainly on moral development in children and adults, but also on links between moral reasoning and democratic communities. Kohlberg is best known for his stage theory of moral development.

Kohlberg posited six stages of moral development, paired to form three levels: pre-conventional, conventional, and post-conventional. Different levels represent qualitatively distinct ways of reasoning about moral problems. Higher stages incorporate elements of lower stages, but focus on new,more worthy moral considerations (judged from the individual’s perspective). Full moral development requires moving from “nonreversible” moral judgments – judgments self-interestedly biased by awareness of social or situational position – to “reversible” ones – judgments that could be accepted from the perspective of any role-player in some moral dilemma. However, few adults reach the highest stages: less than one-fourth reach stage 5, and very few reach stage 6. Moral development can be encouraged through education.

At the lowest, pre-conventional level, children respond to cultural notions of right and wrong, but interpret them in terms of physical or hedonistic consequences. At stage 1, children seek to avoid punishment. At stage 2, children understand right and wrong in terms of instrumental satisfaction of their own needs, and sometimes the needs of others. Notions of reciprocity, fairness, and equality emerge, but are interpreted physically and pragmatically.