Erik Erikson proposed an 8-stage theory of psychosocial development across the lifespan. Each stage is characterized by a psychosocial crisis or challenge that is resolved either positively or negatively. If resolved positively, individuals develop certain virtues that allow healthy development. The stages include trust vs mistrust in infancy, autonomy vs shame and doubt in early childhood, initiative vs guilt in preschool years, industry vs inferiority in school-age children, identity vs role confusion in adolescence, intimacy vs isolation in young adulthood, generativity vs stagnation in middle adulthood, and integrity vs despair in late adulthood.