Erik Erikson's theory of psychosocial development outlines eight stages of personality development that span a person's entire life, contrasting with Freud's focus on early childhood. Each stage includes specific psychosocial challenges that must be negotiated to achieve a healthy personality and overall well-being, reflecting the impact of social, historical, and cultural factors. The theory emphasizes the importance of identity formation and the potential consequences of unresolved conflicts at any stage, shaping an individual's future development.