Lawrence Kohlberg was a 20th century psychologist known primarily for his research into moral psychology and development. 

Professional Life

Lawrence Kohlberg was born in Bronxville, New York on October 25, 1927. Kohlberg enrolled in the University of Chicago, and with high examination scores, he was excused from many required courses and received his bachelor’s degree in just one year. He received his PhD in psychology from the University of Chicago in 1958. His dissertation was based on his research into the moral choices of adolescent boys and led to a life devoted to the exploration of moral and ethical development in young people. 

In 1959, Kohlberg joined the staff of Yale University as an assistant professor of psychology. In 1962, he returned to the University of Chicago as an assistant professor. Over several years, he worked as an associate professor and director of Child Psychology Training Program at the university. The remainder of his career was spent as a professor of education and social psychology at Harvard University between 1968 and 1987.

Kohlberg married Lucy Stigberg in 1955, and the couple had two sons. Kohlberg died of an apparent suicide in 1987, after a long battle with depression coupled with painful symptoms from a tropical parasite he had contracted in Belize in 1971. He parked his car, leaving identifying documents behind, then walked into the frigidly cold Boston Harbor. 

Contribution to Psychology

Kohlberg’s stages of moral development were influenced by the Swiss psychologist Jean Piaget’s stage-based theory of development. Kohlberg expanded on Piaget’s two stages, identifying six stages of moral development. He argued that correct moral reasoning was the most significant factor in moral decision-making, and that correct moral reasoning would lead to ethical behavior. Kohlberg believed that individuals progress through stages of moral development just as they progress through stages of cognitive development.

Kohlberg’s theory of moral development included three levels and six stages:

  • Preconventional Morality:
    • Stage one: Obedience and punishment. The child is motivated to avoid punishment and has little or no independent moral reasoning. 
    • Stage two: Individualism and exchange. Individuals are focused on fulfilling their own self-interests, while acknowledging that different people have different views. 
  • Conventional Morality:
    • Stage three: Maintaining interpersonal relationships. At this stage, individuals emphasize the importance of being kind to other people, engaging in “good” behavior and showing concern for others. This stage includes a strong emphasis on gaining approval. 
    • Stage four: Law and order. The individual is determined to obey the rules, focusing on the value that the law adds to human life. A person at this stage might argue that breaking the law is wrong because the law is designed to protect people. Stage 4 individuals focus on maintaining the social order and upholding cultural norms. 
  • Post-Conventional Morality
    • Stage five: Social contract. People at this stage of development focus on doing what is best for society as a whole and respecting individual rights. Civil disobedience would be endorsed by people in both stages of post-conventional morality. 
    • Stage six: Universal principles. At this stage, individuals are focused on upholding principles of universal justice, fairness, and ethics. They believe in the democratic process, but also endorse disobeying unjust laws. 

To determine which stage of moral development his subjects were in, Kohlberg presented them with invented moral dilemmas, such as the case of a man who stole medicine for his sick wife. According to Kohlberg, few people reach stages five and six; most tend to stay at stage four. 

Criticism and Controversy

Kohlberg purported that women were often at a lower stage of moral development than men, but psychologist Carol Gilligan questioned his findings. Gilligan claims that women place a strong emphasis on caring and empathy, rather than on justice. She developed an alternative scale, heavily influenced by Kohlberg's scale, that showed that both men and women could reach advanced stages of moral development.

Books by Lawrence Kohlberg:

  • The Meaning and Measurement of Moral Development (1981)
  • The Philosophy of Moral Development: Moral Stages and the Idea of Justice (1981)
  • The Psychology of Moral Development: The Nature and Validity of Moral Stages (1984) 
  • Child Psychology and Childhood Education: A Cognitive-Development View (1987)


  1. Walsh, C. (2000). The Life and Legacy of Lawrence Kohlberg. Society, 37(2), 36-41. Retrieved from
  2. Power, F. Clark. (2003). Lawrence Kohlberg. Encyclopedia of Education. Biography In Context. Retrieved from