Study of Adult Development
The Harvard Study of Adult Development, one of the longest-running longitudinal studies of human life in the US, has consistently found that good relationships are the most significant predictor of long-term happiness and health.
This study, which began in 1938 during the Great Depression, has tracked the lives of over 2,000 individuals across three generations, including the original participants: 268 Harvard undergraduates and 456 disadvantaged Boston men, along with their spouses and descendants.
Of the original Harvard cohort recruited as part of the Grant Study, only a few are still alive, all in their mid-90s. Among the original recruits were eventual President John F. Kennedy and longtime Washington Post editor Ben Bradlee. Women weren’t in the original study because the College was still all male.
The research, now in its 86th year, has shown that the quality of relationships, not wealth, status, or professional success, is the key factor in leading a healthy and happy life.
The study’s director, Robert Waldinger, and associate director, Marc Schulz, concluded that “good relationships keep us happier and healthier. Period”. This finding is supported by data showing that men with the warmest relationships earned significantly more over their lifetimes, averaging $243,000 annually compared to $102,000 for those with the poorest relationships. On top of that they were far more likely to achieve professional success.
The capacity for intimate relationships was found to predict flourishing in all aspects of life, including career, health, and emotional well-being.
Loneliness kills. It’s as powerful as smoking or alcoholism
The benefits of strong relationships extend beyond romantic partnerships; close bonds with friends, family, and colleagues are equally vital for well-being.
The study emphasizes that relationships must be nurtured over time, much like physical health, and that the quality of these connections is paramount. In other words unhealthy or toxic relationships do not contribute to happiness.
Early childhood relationships, particularly with mothers, are linked to later success and health, while warm relationships with fathers correlate with lower anxiety and greater life satisfaction in old age.
The research also highlights that the ability to form and maintain close relationships is a key factor in resilience and adaptation throughout life.
Ultimately, the study’s central takeaway, as articulated by former director George Vaillant, is that “Happiness is love. Full stop”.
This conclusion is based on the decades of data which shows that supportive, reciprocal relationships help the nervous system relax, protect the brain from decline, and reduce both emotional and physical pain.
The study underscores that while the path to happiness may be complex, the evidence points to the enduring power of meaningful human connection.
Studying the second generation
Harvard has begun to study the children of our original participants: the second generation of the Study of Adult Development. This new project aims to study the effect of childhood experiences on midlife health.