The 8-Stage Personality Theory by Erik Erikson

Although Erik Erikson (Berkeley and Harvard University) is considered one of the so-called Freudian ego psychologists and, like Freud, considers different stages of development in his 8-stage theory, his theoretical perspective extends from adolescence into late adulthood. Erikson places less emphasis solely on instinctive drives or the unconscious, and additionally considers a psychosocial and psychohistorical component. Furthermore, in his developmental view, he tends to assume so-called epigenetic stages, meaning a sequence of stages where mastering a developmental task and learning at one stage serve as a foundation for the next stage.

His theory postulates that each developmental task can be associated with conflicts and crises, and sometimes may not be fully mastered at one stage; rather, a comprehensive mastery of the developmental task at one stage facilitates entry into the next.