The Good Life: Lessons From the World's Longest Scientific Study of Happiness

Robert Waldinger, a psychiatrist and psychoanalyst, and Marc Schulz, a clinical psychologist and professor, are the current director and associate director of the Harvard Study of Adult Development, an ongoing longitudinal study begun in 1938 that has tracked participants from adolescence into old age. The study now encompasses three generations and more than 1,300 descendants of its original 724 participants. Drawing on this dataset and hundreds of corroborating studies, the authors advance a central claim: Good relationships are the most consistent and powerful factor tied to physical health, mental health, and longevity.

The book opens by challenging the assumption that wealth or career success will bring lasting happiness. The authors counter that the good life is not a destination but an unfolding process, "forged from precisely the things that make it hard" (3). They introduce eudaimonia, Aristotle's term for well-being rooted in meaning and purpose, and note that they use "happiness" throughout in this deeper sense. The study's methods are illustrated through Henry and Rosa Keane, a married couple in their 70s; Henry has been a participant since age 14. When asked about their greatest fears, Rosa worries Henry will fall seriously ill; Henry fears he will outlive Rosa. The study originated with two groups: 268 Harvard College sophomores selected because they appeared likely to thrive, and 456 inner-city Boston boys from disadvantaged families. The authors acknowledge the sample's original limitation of including only White males, noting that the study has since expanded and that the book emphasizes findings corroborated by diverse populations globally. After 84 years, one finding stands above all: "Good relationships keep us healthier and happier. Period" (10). Relationship satisfaction at age 50 predicted health at age 80 better than cholesterol levels.

To explain why people overlook relationships, the authors examine cognitive and cultural factors. A University of Chicago experiment found that commuters predicted talking to a stranger would be unpleasant, yet those instructed to do so rated their commute as better than usual, illustrating the systematic tendency to misjudge what brings happiness. The authors also cite a 2010 study by Angus Deaton and Daniel Kahneman showing that household income above approximately $75,000 per year had no clear relationship to daily emotional well-being. Money matters most for basic needs and security; beyond that, its effect on happiness diminishes sharply.

Two participants crystallize the contrast. John Marsden, a wealthy Harvard graduate who became a successful lawyer, consistently reported deep unhappiness and disconnection, preoccupied with personal achievement. Leo DeMarco gave up his dream of becoming a writer to care for his mother, became a high school teacher, and invested in relationships throughout his life, rating himself "very happy" or "extremely happy" for decades. The authors return to these two men repeatedly as emblems of their argument.

The book traces how relationships evolve across the lifespan through Wes Travers, an inner-city participant whose father abandoned the family when Wes was seven after years of violence. At 15, Wes dropped out of school to support his family. At 19, he joined the military, gaining his first real friendships. After overseas military and government work, he returned home and built an active social life but avoided romantic commitment. Only at 44 did he propose to Amy, his longtime partner. At 81, asked what he and Amy enjoyed most, Wes wrote: "Just being together" (84). Drawing on Erik and Joan Erikson's model of developmental crises and Bernice Neugarten's concept of the "social clock," the culturally expected timeline for milestones such as marriage and parenthood, the authors describe relational challenges from adolescence through late life and stress that unexpected events often shape lives more than any plan.

The concept of "social fitness" is introduced: just as sedentary life requires deliberate exercise, modern life requires effort to maintain relationships. Sterling Ainsley, a Harvard College participant raised in traumatic circumstances, illustrates the cost of neglect. Despite being shaped by a devoted older sister and a loving adoptive mother, Sterling lost touch with both and by his 60s lived alone in Montana with no close confidant. Data show that chronic loneliness increases one's odds of death in any given year by 26 percent. Three strategies for improvement are offered: generosity, which research links to happiness through a neural feedback loop; learning new relational patterns, since a positive adult relationship can reshape assumptions formed in childhood; and radical curiosity about other people.

Attention, the authors argue, is the most valuable resource for relationships. A 2010 study across 83 countries found that people spend close to half their waking moments thinking about something other than what they are doing, and that a wandering mind correlates with unhappiness. The authors address social media, acknowledging its benefits while noting that passive scrolling worsens mood and that virtual connection cannot replicate physical presence. They present the W.I.S.E.R. model (Watch, Interpret, Select, Engage, Reflect) as a framework for managing emotional reactions in relationships by slowing reflexive responses and encouraging careful observation, interpretation, and reflection.

Intimate partnerships receive extended treatment. The authors trace attachment theory from psychologist Mary Ainsworth's "Strange Situation" research, which observed how infants responded to brief separations from caregivers, to its implications for adult relationships. In one of the authors' earliest joint studies, untrained observers watching videotaped couples predicted with close to 85 percent accuracy which couples would remain together five years later; the strongest predictors were displays of affection and empathy. A later study found that empathic effort, a partner's perception that the other was genuinely trying to understand, mattered even more than empathic accuracy. The authors argue that disagreements are opportunities to uncover hidden vulnerabilities, not failures. Study participant Joseph Cichy's 59-year marriage to his wife Olivia was stable but emotionally guarded; Leo described his bond with his wife Grace as "Comforting, Challenging, Feisty, Pervasive, Beautiful" (185).

Family relationships are explored through Neal "Mac" McCarthy, an inner-city participant whose warm early childhood gave way to violence when his mother's alcohol addiction escalated. Research from the study shows that men with warmer childhood environments were more likely to be securely attached to partners decades later, though the ability to process emotions remains malleable at any age. Psychologist Emmy Werner's Kauai Longitudinal Study, which tracked children born on the Hawaiian island of Kauai in 1955 for over 30 years, reinforces this point: One third of children with adverse childhoods grew into well-adjusted adults, often because at least one caring adult was consistently present.

The chapter on work argues that the boundary between "work life" and "real life" is false. Henry Keane sought volunteer and part-time work in retirement because he loved being around people, and Gallup research shows that people with a best friend at work are significantly more engaged. The authors address workplace inequities, citing Rebecca Taylor, a participant in the Student Council Study of students at three northeastern colleges, who overheard doctors dismissing the importance of nurses' work. As remote work, artificial intelligence, and the gig economy reduce in-person contact, the authors urge readers to be intentional about cultivating connection.

The chapter on friendship cites evidence that strong friend networks reduce mortality risk and buffer against adversity, including post-traumatic stress disorder (PTSD). Harvard Study data show that men with more positive wartime friendships were less likely to develop PTSD symptoms. Andrew Dearing's story closes the section. One of the most isolated participants, Andrew attempted suicide at 45 and reported having no friends. After separating from his wife at 68, he began visiting a health club on impulse. Within months he had more friends than ever. In his 80s, he rated his life as close to ideal. "It wasn't too late," the authors write. "Because the truth is, it's never too late" (271).

The conclusion reaffirms the central finding: "Good relationships keep us happier, healthier, and help us live longer" (278). The authors advocate for relationships as a "fourth R" in education alongside reading, writing, and arithmetic, and end with a direct appeal: Think of one person who may not know how much they mean to you, and tell them now.