The scientific search for the secret of happiness continues, and one of the longest-running studies of mental and physical well-being -- the Harvard Study of Adult Development -- provides some interesting, if unsurprising, insights. A long article in the June edition of the Atlantic Online presents some of the findings from this study of 268 men who entered Harvard in the late 1930s and have been followed up ever since. The author, Joshua Wolf Shenk, was allowed to read personal files (anonymously) and he interviewed the main interpreter of the case histories, psychiatrist George Vaillant.

Dr Arlie Bock, who was in charge of health services at Harvard in the 1930s, launched the study with the aim of shedding light on the subject of healthy living. He chose undergraduates who were healthy and well-adjusted and who were to be measured from every conceivable angle; he thought their histories would provide knowledge that would reduce “the disharmony of the world at large”. Some were very successful indeed: four ran for the US Senate; one served in a presidential cabinet, and one was president -- John F Kennedy. One was a best-selling novelist and another the longtime editor of the Washington Post, Ben Bradlee, who has written about his involvement.

By age 50, however, almost a third of the Grant Study men (named for the study’s first patron, W T Grant) had at one time or another met Vaillant’s criteria for mental illness. “Arlie Bock didn’t get it. ‘They were normal when I picked them,’ he told Vaillant in the 1960s. ‘It must have been the psychiatrists who screwed them up.’”

Vaillant, however, has been interested not so much in how much or little trouble the men ran into, as in how they responded to that trouble. He has mainly looked at their stories through the lens of “adaptations”, or unconscious responses to pain, conflict or uncertainty (a variation on Freudian “defence mechanisms”), reports Wolf Shenk. Vaillant observes that people change a lot in the course of their lives -- which shouldn’t surprise those of us who have lived long enough.

“As adolescents, the Grant Study men were twice as likely to use immature defenses as mature ones, but in middle life they were four times as likely to use mature defenses—and the progress continued into old age. When they were between 50 and 75, Vaillant found, altruism and humor grew more prevalent, while all the immature defenses grew more rare.”

“This means that a glimpse of any one moment in a life can be deeply misleading. A man at 20 who appears the model of altruism may turn out to be a kind of emotional prodigy—or he may be ducking the kind of engagement with reality that his peers are both moving toward and defending against. And, on the other extreme, a man at 20 who appears impossibly wounded may turn out to be gestating toward maturity.”

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.

Early shyness tends to disappear:

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’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.”

Data from another study used by Vaillant -- a study of juvenile delinquents in inner-city Boston begun in 1939 and now defunct -- showed something else:

“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.’”

A stable marriage, having a close brother or sister, a busy, purposeful childhood -- no great revelations here, but confirmation of some things that we know from experience make for happiness, even though they may be missing from many otherwise privileged lives today.