What allows people to work, and love, as they grow old? By the time the Grant Study men had entered retirement, Vaillant, who had then been following them for a quarter century, had identified seven major factors that predict healthy aging, both physically and psychologically.
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.
What factors don’t matter? Vaillant identified some surprises. Cholesterol levels at age 50 have nothing to do with health in old age. While social ease correlates highly with good psychosocial adjustment in college and early adulthood, its significance diminishes over time. The predictive importance of childhood temperament also diminishes over time: shy, anxious kids tend to do poorly in young adulthood, but by age 70, are just as likely as the outgoing kids to be “happy-well.” Vaillant sums up: “If you follow lives long enough, the risk factors for healthy life adjustment change. There is an age to watch your cholesterol and an age to ignore it.”
The study has yielded some additional subtle surprises. Regular exercise in college predicted late-life mental health better than it did physical health. And depression turned out to be a major drain on physical health: of the men who were diagnosed with depression by age 50, more than 70 percent had died or were chronically ill by 63. More broadly, pessimists seemed to suffer physically in comparison with optimists, perhaps because they’re less likely to connect with others or care for themselves.
More than 80 percent of the Grant Study men served in World War II, a fact that allowed Vaillant to study the effect of combat. The men who survived heavy fighting developed more chronic physical illnesses and died sooner than those who saw little or no combat, he found. And “severity of trauma is the best predictor of who is likely to develop PTSD.” (This may sound obvious, but it countered the claim that post-traumatic stress disorder was just the manifestation of preexisting troubles.) He also found that personality traits assigned by the psychiatrists in the initial interviews largely predicted who would become Democrats (descriptions included “sensitive,” “cultural,” and “introspective”) and Republicans (“pragmatic” and “organized”).

 

 

 

 

 

 

 

In contrast to the Grant data, the Glueck study data suggested that industriousness in childhood—as indicated by such things as whether the boys had part-time jobs, took on chores, or joined school clubs or sports teams—predicted adult mental health better than any other factor, including family cohesion and warm maternal relationships. “What we do,” Vaillant concluded, “affects how we feel just as much as how we feel affects what we do.”