Answer: In research on diverse samples of adults followed over the lifespan, George Vaillant looked at how various life-course factors contributed to late-life physical and psychological well-being. Findings revealed that factors people can control to some degree (such as health habits, coping strategies, marital stability, and years of education) far outweighed uncontrollable factors (parental SES, family warmth in childhood, early physical health, and longevity of family members) in predicting a satisfying, active old age. Vaillant concluded, “The past often predicts but never determines our old age.” Successful aging is an expression of remarkable resilience during this final period of the lifespan.