Kohlberg (1968) used a longitudinal and cross-cultural methodology to study moral development. He followed 75 American boys from age 10 to 28, interviewing them every three years using moral dilemmas. Each participant was asked to discuss three hypothetical scenarios, such as the Heinz dilemma, and their responses were analysed for patterns in moral reasoning. Kohlberg also used the same interview technique with participants in countries like Taiwan and Mexico to compare moral development across cultures.
