AP Psychology Practice Test

The theorist known for developing the stages of moral development is Lawrence Kohlberg. He proposed a framework outlining how individuals progress through different levels of moral reasoning as they grow and mature. Kohlberg's theory is built on the premise that morality evolves through a series of six stages grouped into three levels: pre-conventional, conventional, and post-conventional. Each stage represents a different approach to understanding right from wrong, highlighting how cognitive development influences moral reasoning.

Piaget, while an influential psychologist, focused more on cognitive development rather than moral stages specifically. Marcia's work is centered on identity development in adolescence, and Erikson is known for his theory of psychosocial development, which also does not specifically address moral reasoning. Thus, Kohlberg is the correct choice as he directly theorized the stages of moral development.