A few researchers have looked at this cohort to understand what drives their unhappiness. It is, in a word, irrelevance. In 2007, a team of academic researchers at UCLA and Princeton analyzed data on more than 1,000 older adults. Their findings, published in the Journal of Gerontology, showed that senior citizens who rarely or never “felt useful” were nearly three times as likely as those who frequently felt useful to develop a mild disability, and were more than three times as likely to have died during the course of the study.

One might think that gifted and accomplished people, such as the man on the plane, would be less susceptible than others to this sense of irrelevance; after all, accomplishment is a well-documented source of happiness. If current accomplishment brings happiness, then shouldn’t the memory of that accomplishment provide some happiness as well?

Maybe not. Though the literature on this question is sparse, giftedness and achievements early in life do not appear to provide an insurance policy against suffering later on. In 1999, Carole Holahan and Charles Holahan, psychologists at the University of Texas, published an influential paper in The International Journal of Aging and Human Development that looked at hundreds of older adults who early in life had been identified as highly gifted. The Holahans’ conclusion: “Learning at a younger age of membership in a study of intellectual giftedness was related to … less favorable psychological well-being at age eighty.”