Sigmund Freud's Theory of Psychosexual Development Sigmund Freud’s psychosexual theory of development is one of the most famous, foundational, and controversial frameworks in the history of psychology. Proposed in the late 19th and early 20th centuries, this psychoanalytic theory suggests that human personality is largely established by the age of five. Freud believed that early childhood experiences play a critical role in shaping adult motives, personality traits, and psychological well-being. At the core of this theory is the idea that human beings are driven by a fundamental, biological psychic energy called libido . According to Freud, this libidinal energy fuels human behavior and is focused on different erogenous zones (areas of the body particularly sensitive to pleasure) at specific stages of childhood. How a child navigates the conflicts at each of these stages determines their future psychological health and personality structure. Foundational Concepts To understand t...