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...