Early schools of thought in psychology, such as structuralism, functionalism, behaviorism, and psychoanalysis, laid the foundation for modern psychology by introducing key concepts and methodologies. For example, structuralism emphasized introspection as a method to analyze conscious experience, while behaviorism focused on observable behavior and its relationship to stimuli. Psychoanalysis highlighted the importance of unconscious processes and the role of early childhood experiences in shaping behavior. These early schools of thought influenced the development of modern psychological theories and approaches.