Erik Erikson proposed eight stages of psychosocial development across the human lifespan. Each stage presents a developmental crisis centered around a key conflict that helps shape a person's identity. The stages include trust vs mistrust in infancy, autonomy vs shame and doubt in toddlerhood, initiative vs guilt in preschool years, industry vs inferiority in elementary school years, identity vs identity confusion in adolescence, intimacy vs isolation in early adulthood, generativity vs stagnation in middle adulthood, and integrity vs despair in late adulthood. Successful resolution of earlier crises helps individuals navigate later stages of development.