Neither the timing nor the process of becoming adult are universalistic or biologically determined. Throughout Western history, there has been increasing differentiation of early life stages, postponement of entry to adulthood, and change in the status positions from which adulthood is launched (Klein 1990).
Some scholars argue that in medieval times persons moved directly from a period of infancy, when small size and limited strength precluded productive work, to adulthood, at which time younger persons began to work alongside their elders (Ariés 1962). A new stage of childhood, between infancy and adulthood, arose with the emergence of schools. As economic production shifted from agriculture to trade and industry, persons increasingly entered adulthood after a stage of apprenticeship or ‘‘child labor.’’
By the beginning of the twentieth century, with schooling extended and child labor curtailed, adolescence gained recognition as the life stage preceding adulthood (Hall 1904). The adolescent, though at the peak of most biological and physiological capacities, remained free of adult responsibilities.
With more than 60 percent of contemporary young people obtaining some postsecondary education (Halperin 1998), a new phase of ‘‘youth’’ or ‘‘postadolescence’’ has emerged, allowing youth in their mid-to-late twenties, and even older youth, to extend the preadult ‘‘moratorium’’ of continued exploration. This youth phase is characterized by limited autonomy but continued economic dependence and concern about the establishment of adult identity (Keniston 19
