Freud's theory of personality posits that personality results from the interaction between the id, ego, and superego. The id operates on the pleasure principle, seeking instant gratification of needs. The superego incorporates societal morals and standards. The ego balances the demands of the id and superego using the reality principle. Freud also proposed psychosexual stages of development from infancy through adulthood that shape personality. Marketers can apply these concepts to better understand consumer behavior and develop persuasive branding strategies that tap into unconscious desires.