This article examines the role of rapid social change for human adaptation, focusing in particular on uncertainty in educational and career-related goals of young people born between 1970 and 1990. A review of the research evidence suggests that although most young people want to continue in higher education, more young people in the later-born cohort are uncertain regarding their occupational career destination than those in the earlier-born cohorts. Examining the longer-term consequences of teenage aspirations suggests that uncertainty can be beneficial or harmful, depending on the wider sociohistorical context in which decisions are made, the timing and urgency of imminent educational and career choices, the individual characteristics of the adolescents themselves, and the support available from parents and the wider social context. The findings are discussed in terms of development as action in changing contexts, taking into account how young people negotiate changing demands in an uncertain economic and social context. (Contains 35 notes.)