This document summarizes five theories of human development:
1. Freud's psychoanalytic theory focuses on psychosexual stages from birth to adulthood.
2. Sullivan's interpersonal theory emphasizes how relationships shape personality development through stages of infancy to late adolescence.
3. Erikson's psychosocial theory describes eight stages from infancy to late adulthood defined by resolving psychosocial crises through developing relationships and skills.
4. Piaget's cognitive development theory outlines stages from infancy through formal operations centered around developing logical and abstract thinking abilities.
5. Peplau's interpersonal relations theory applies relationships to nursing by outlining nurse-client processes and roles through developmental stages from infancy to late