This document provides an overview of key people, approaches, theories, studies, and concepts in psychology. It summarizes Wundt as establishing introspection; Freud's contributions including psychoanalysis and stages of development; Milgram studying obedience; and Skinner's operant conditioning research with rats and pigeons. Theories covered include Piaget's stages of cognitive development, Kohlberg's model of moral development, and Erikson's psychosocial stages. Important studies are highlighted such as Milgram's obedience experiment and Zimbardo's Stanford prison experiment.