The Longevity Project

In 1921, Stanford University psychologist Lewis Terman selected approximately 1,500 gifted children born around 1910 in California to study the sources of intellectual leadership, collecting extensive data on their personalities, families, and activities. Terman died in 1956, but the project continued. In 1990, psychologists Howard S. Friedman and Leslie R. Martin began their own decades-long follow-up, gathering death certificates to determine how long each participant lived and from what cause. Their book presents the findings of this eight-decade investigation into why some people thrive into old age while others die prematurely.

Friedman and Martin argue that standard health advice is often ineffective or wrong. They label widely held beliefs as "dead-end myths": that marriage guarantees longer life, that worrying is harmful, and that cheerful children grow up to be healthier adults. The long-lived Terman participants did not find the secret to health in broccoli, vitamins, or jogging. Instead, these individuals had constellations of habits, personality traits, and social relationships that placed them on what the authors call healthy "pathways."

The book's central finding is that conscientiousness, the quality of being prudent, persistent, well-organized, and dependable, is the single strongest personality predictor of longevity. When parents and teachers rated the children in 1922, the most conscientious went on to live the longest, and adults who described themselves as thrifty, persistent, and detail-oriented in 1940 showed the same pattern. Conscientious people engage in fewer risky behaviors such as smoking and heavy drinking; they appear biologically predisposed to be healthier, possibly due to differences in brain chemistry; and most importantly, conscientiousness leads people into healthier social environments, including better marriages, stronger friendships, and more stable work situations. Personality change also matters: A participant they call James scored low on conscientiousness as a child but became more responsible in adulthood and lived to old age.

Contrary to expectations, sociability does not straightforwardly predict long life. Participants who became scientists were much less sociable than those who became businessmen and lawyers, yet the scientists outlived the nonscientists because they moved into stable jobs and lasting marriages. Sociable children, meanwhile, grew up to drink and smoke more. Sociability, the authors conclude, carries both benefits and risks.

One of the book's most striking findings concerns cheerfulness. Children rated as exceptionally cheerful and optimistic died younger on average, an effect comparable to known risk factors like high blood pressure or high cholesterol. The cheerful children grew up to drink more, smoke more, and pursue riskier hobbies. The authors reject what they call the "Tinker Bell Principle," the idea that positive thinking can cure serious illness. Happiness and health are correlated, they contend, not because happiness causes health but because both result from the same underlying patterns of living.

The authors distinguish ordinary worrying from catastrophic thinking, the tendency to interpret every setback as a sign of pervasive doom. Content analysis of participants' written responses reveals that catastrophizers died sooner, especially from accidents and violence. They present the case of Douglas Kelley, a publicly identified participant who served as a psychiatrist at the Nuremberg trials of Nazi leaders and died by suicide in 1958, swallowing cyanide as Hermann Goering had. Moderate worrying, however, proves beneficial: Neurotic Terman men were actually less likely to die than their calmer counterparts, apparently because anxiety motivated them to take better care of their health.

Turning to childhood and education, the authors find that early health indicators such as birth weight and breast-feeding had little long-term significance for longevity. Starting formal schooling at age five, however, predicted shorter life compared to starting at the traditional age of six, as early entry deprived precocious children of unstructured playtime and could push them onto erratic paths.

Parental divorce emerges as the single strongest social predictor of early death, reducing life span by approximately five years on average. The death of a parent, though traumatic, had no measurable long-term effect on mortality. Divorce operated through multiple channels: Children of divorce ended their education earlier, smoked and drank more, and were much more likely to divorce themselves, placing them at greater mortality risk. Participants Patricia and James, both children of divorce, illustrate resilience: Both established good marriages, avoided smoking, and achieved personal satisfaction by midlife.

The authors challenge conventional exercise advice by showing that physical activity levels are personal and pattern-based. Being active in middle age matters most; childhood athletes who slowed down did not live longer, while sedentary children who became active later often did. Excessive exercise can itself be unhealthy.

The book dismantles the myth that marriage universally promotes longevity. Dividing participants into steadily married, remarried, divorced, and steadily single groups, the authors find sharply different patterns by sex. Steadily married men lived longest, while divorced men fared worst, with fewer than a third reaching age 70. For women, those who divorced and did not remarry lived nearly as long as steadily married women. Marital happiness data from 1940 revealed that the husband's happiness predicted both partners' later health, while the wife's independent happiness added little additional predictive information.

Hard work and career success promote rather than undermine health. The most professionally successful men lived approximately five years longer than the least successful. Damaging workplace stress arises from interpersonal conflicts and lack of control rather than from demanding work itself. Among participants over age 70, those who remained productive lived much longer than their more laid-back counterparts.

Religious involvement at midlife predicted longer life for women but not for men. The authors conclude that the social engagement associated with religious participation, not prayer or devotion itself, explains the health benefits. Examining social support more broadly, they find that the size of one's social network and helping others matter more to longevity than feeling loved and cared for.

The authors explore the gender gap in longevity using measures of psychological masculinity and femininity based on occupational preferences. More masculine men and women had increased mortality risk, while more feminine men and women were relatively protected. Widowed Terman women tended to thrive, while widowed men generally fared poorly, except for neurotic worriers, whose mortality risk dropped by half, apparently because anxiety motivated them to monitor their own health.

Wartime stress produced lasting health effects. Terman men who served overseas in World War II were more than one and a half times as likely to die in any given postwar year as those who served stateside. Combat veterans were more likely to develop drinking problems and less likely to complete their education, raising postwar mortality risk. Less conscientious participants were more likely to end up in the most dangerous operations, suggesting that personality shaped even wartime exposure to risk.

In a concluding synthesis, the authors identify several common pathways to long life: conscientious individuals with good marriages; hard-working achievers who thrived despite stress; introverted but stable people who found connection through work; and women who stayed single or chose not to remarry. They contrast these with unhealthy pathways marked by catastrophic thinking, excessive optimism, and cascading unhealthy behaviors. The authors argue against "polypill" approaches, proposed multi-drug preventive pills intended for broad population use, contending that pathway configurations matter far more than any single intervention. They call for rethinking public health, arguing that well-adjusted citizens integrated into their communities represent society's best path to long life.