Kohlberg studied moral development by posing moral dilemmas to children of different ages.
He was interested in how individuals reason through moral issues and how their reasoning changes as they grow. By presenting these dilemmas, such as the well-known Heinz dilemma, he was able to analyze the reasoning behind their decisions. Kohlberg identified different stages of moral development, which reflected a progression from simple, concrete reasoning based on rewards and punishments to more complex, abstract principles of justice and rights. His work highlighted the importance of cognitive development in moral reasoning and has had a significant influence on psychology and education.