This document provides an overview of the history and major approaches in psychology. It discusses how psychology originated in philosophy and was influenced by thinkers like Descartes, Locke, and Hobbes. Key schools of thought discussed include structuralism, functionalism, psychoanalysis, behaviorism, cognitive psychology, humanism, biopsychology, evolutionary psychology, sociocultural psychology, and the biopsychosocial model. Each school of thought proposes different causes of behavior and uses varying methods for investigation such as introspection, therapy, experimentation, and cross-cultural studies.