How did Kohlberg organise moral development?

1. Kohlberg used a stage model similar to Piaget's. 2. He proposed six stages of moral reasoning. 3. They are grouped into three levels of two stages each: preconventional, conventional and postconventional. **Why not the others:** Eight stages across life describes Erikson's psychosocial theory. _Source: Seifert and Sutton, Educational Psychology, 2nd ed. (2009, CC BY 3.0), Ch 3, section "Kohlberg’s morality of justice", p. 57_