The Harvard Study of Adult Development one of the most comprehensive longitudinal studies ever conducted, has sought to answer a fundamental question that resonates with each of us: What makes a good life?

When asked what they think would make them happiest, most people answered money or fame. This didn’t turn out to be the case.

People who are happiest and healthiest have strong, supportive bonds with family, friends, and their community. These relationships provide emotional support, enhance mental well-being, and even protect against physical health decline. The study highlights that it’s not just about having many relationships but nurturing those that are deep, trusting, and reliable.

“The surprising finding is that our relationships and how happy we are in our relationships has a powerful influence on our health,” said Robert Waldinger, director of the study, a psychiatrist at Massachusetts General Hospital and a professor of psychiatry at Harvard Medical School. “Taking care of your body is important, but tending to your relationships is a form of self-care too. That, I think, is the revelation.”

According to the study, the things that make people happiest are:

• Strong, supportive relationships: Quality over quantity; having reliable, emotionally supportive connections.
• Emotional resilience and positive outlook: Ability to cope with stress and view challenges as opportunities for growth.
• Healthy lifestyle choices: Maintaining physical health through regular exercise, a balanced diet, avoiding smoking, and moderating alcohol consumption.
• Social engagement and community involvement: Being actively involved in social networks and community activities.
• Purposeful work and retirement: Finding meaning in one’s work and staying engaged after retirement.
• Early-life experiences: A nurturing early environment sets the foundation for healthier adult relationships and well-being.
• Regular self-reflection on social fitness: Assessing and nurturing important relationships continuously throughout life.

The study

Starting in 1938 during the Great Depression, the study initially sought to uncover clues to leading healthy and happy lives by tracking the health and well-being of 268 Harvard sophomores. Over 85 years later, the study has expanded far beyond its original cohort, incorporating the lives of thousands to reveal a simple yet powerful truth: the quality of our relationships is the single most important factor in determining our overall happiness and longevity.

When the study began, researchers focused on a cohort of 268 young men, all sophomores at Harvard College, hoping to understand the factors that contribute to a healthy and happy life.

The world was a different place then; genetics and biological determinism were the dominant views. The initial phase of the study involved detailed anthropometric measurements, analysis of intellectual abilities, personality traits, and even handwriting. Among the original participants were some notable names, such as future President John F. Kennedy and longtime Washington Post editor Ben Bradlee.

As time went on, the study’s focus shifted. Under subsequent directors, including George Vaillant in the 1960s and Robert Waldinger more recently, the study began to explore the role of relationships, social connections, and emotional well-being as key components of a long and healthy life.

By the 1970s, the research expanded to include 456 Boston inner-city residents, providing a broader socio-economic perspective. Today, over 1,300 of the original participants’ descendants continue to be part of this ongoing research, providing insights into how early-life experiences affect health and aging across generations.

Relationships: The Key to Happiness and Longevity

The data revealed that individuals more socially connected to family, friends, and community live longer, happier lives than those who are less connected. Moreover, it isn’t just the number of relationships that matters, but the quality of those connections. The study found that the people most satisfied in their relationships at age 50 were the healthiest at age 80. This finding holds across different socio-economic backgrounds, including both the Harvard men and the inner-city participants.

The detrimental effects of loneliness were another striking finding. The study demonstrated that loneliness can be as harmful as smoking or alcoholism. Individuals who reported feeling lonely were more likely to experience physical and mental health decline, and they had a higher risk of premature death.

Waldinger emphasized this point in his widely viewed TED Talk, which you can see below. The implication is clear: nurturing meaningful relationships isn’t just beneficial—it’s vital for our health and longevity.

“When we gathered together everything we knew about them about at age 50, it wasn’t their middle-age cholesterol levels that predicted how they were going to grow old,” said Waldinger in a popular TED Talk. “It was how satisfied they were in their relationships. The people who were the most satisfied in their relationships at age 50 were the healthiest at age 80.”

Health, Lifestyle Choices, and “Social Fitness”

While relationships and mindset are crucial, the Harvard Study also points to the importance of health and lifestyle choices. The data reveals that maintaining a healthy weight, staying physically active, and avoiding smoking and excessive alcohol consumption are significant predictors of a long, happy life. Participants who adopted healthy habits earlier in life were more likely to enjoy better physical health and cognitive function as they aged.

Interestingly, the study also introduced the concept of “social fitness,” which involves regularly taking stock of one’s relationships and ensuring they are healthy and balanced.

Just like physical fitness, social fitness requires effort and commitment. Waldinger and Marc Schulz, the study’s associate director, argue that we should approach our relationships as living systems that need nurturing and exercise. This could involve consciously setting aside time to nurture meaningful connections or reflecting on whether we are devoting enough time to the people who matter most to us.

What you can take from this

The lessons from the Harvard Study of Adult Development are particularly relevant in today’s fast-paced, technology-driven world. We all feel some pressure to achieve wealth, status, and success, but the study’s message is clear. The most important aspects of a good life are often the simplest: nurturing meaningful relationships, maintaining a positive and resilient mindset, making healthy lifestyle choices, and engaging with the community.

As for the study, even after more than eight decades, the Harvard Study of Adult Development continues to evolve and expand. The study now includes over 1,300 descendants of the original participants, with researchers exploring new areas such as the impact of technology on relationships, the role of genetics in aging, and the influence of social policies on quality of life.

Waldinger hopes to extend the study to include third and fourth generations, recognizing that this ongoing research offers a unique opportunity to deepen our understanding of human development across lifetimes.