What allows people to work, and love, as they grow old? (중략) Employing mature adaptations was one. The others were education, stable marriage, not smoking, not abusing alcohol, some exercise, and healthy weight. Of the 106 Harvard men who had five or six of these factors in their favor at age 50, half ended up at 80 as what Vaillant called “happy-well” and only 7.5 percent as “sad-sick.” Meanwhile, of the men who had three or fewer of the health factors at age 50, none ended up “happy-well” at 80. Even if they had been in adequate physical shape at 50, the men who had three or fewer protective factors were three times as likely to be dead at 80 as those with four or more factors.

Vaillant’s other main interest is the power of relationships. “It is social aptitude,” he writes, “not intellectual brilliance or parental social class, that leads to successful aging.” Warm connections are necessary—and if not found in a mother or father, they can come from siblings, uncles, friends, mentors. The men’s relationships at age 47, he found, predicted late-life adjustment better than any other variable, except defenses. Good sibling relationships seem especially powerful: 93 percent of the men who were thriving at age 65 had been close to a brother or sister when younger. In an interview in the March 2008 newsletter to the Grant Study subjects, Vaillant was asked, “What have you learned from the Grant Study men?” Vaillant’s response: “That the only thing that really matters in life are your relationships to other people.”

“Their lives were too human for science, too beautiful for numbers, too sad for diagnosis and too immortal for bound journals." (중략) Indeed, the lives themselves—dramatic, pathetic, inspiring, exhausting—resonate on a frequency that no data set could tune to.