the organization of the personality in terms of its basic, enduring components and their relationship to each other. Structural theories vary widely according to their key concepts and include, for example, the personal dispositions proposed by Gordon W. Allport; the surface traits and source traits in Cattell’s personality trait theory; the id, ego, and superego in Sigmund Freud’s theory; the individual style of life posited by Alfred Adler; and the needs and motivations in Maslow’s motivational hierarchy.