What are the stages of moral development according to Kohlberg?

Lawrence Kohlberg proposed three levels of moral development, each with two stages. The preconventional level focuses on self-interest: stage one avoids punishment and stage two seeks personal reward. The conventional level focuses on social rules: stage three seeks social approval from others and stage four upholds law and order for society's sake. The postconventional level focuses on universal ethical principles: stage five recognizes that laws are social contracts that can be changed, and stage six follows abstract principles of justice even when they conflict with laws.