Sigmund Freud's psychosexual theory and Erik Erikson's psychosocial theory are two well-known theories of development. While he was influenced by Freud's ideas, Erikson's theory differed in a number of important ways. Like Freud, Erikson believed that personality develops in a series of predetermined stages. Unlike Freud’s theory of psychosexual stages, Erikson’s theory describes the impact of social experience across the whole lifespan. Compare and contrast these two theories by looking at the overview of developmental stages provided in the chart below.