Kohlberg's theory of moral development is based on the idea that, as children get older, their reasoning in moral dilemmas develops and becomes more sophisticated. This theory was founded on the results of Kohlburg's experiments with children using the Hienz Dilemma.
In this theory of moral development, there are three stages of morality that apply to children and adults at different age groups. The first stage is pre-conventional morality that applies to children nine and younger. In this stage, children do not have their own personal code of morality but base moral decisions on what adults have told them to do.
In the second stage, conventional morality, which applies to most adolescents and adults, people internalize the moral codes of their role models and form their own personal code. The motivation for being moral in this stage is to maintain relationships with others and membership in one's social groups. The concept of authority is also internalized into one's moral code, but no necessarily questioned
Stage three is post-conventional morality where people's moral codes are based on the principles of justice and human rights. Part of this step is the realization that laws don't necessarily reflect morality, and it is possible that defending universal humans may require illegal activities.