The Harvard Study of Adult Development

The story

It started in 1938, in the shadow of the Great Depression, with two groups of young men who could hardly have been more different: 268 Harvard College sophomores, and — through the allied Glueck study — 456 boys from Boston's poorest inner-city neighborhoods. 724 men in all. The researchers wanted to know something deceptively simple: what actually makes people healthy and happy across a whole life?

So they kept asking. Year after year, decade after decade, the study gathered questionnaires, interviews, and medical records, and in later years added genetic data and brain imaging. The men grew up, went to war, married, worked, divorced, retired, and grew old — and the study, remarkably, refused to die alongside its funding cycles. It became the longest in-depth longitudinal study of adult life ever done.

Today it runs out of Massachusetts General Hospital and Harvard Medical School under psychiatrist Robert Waldinger, with Marc Schulz as his co-author and collaborator. The men's wives joined the study more than a decade ago, and the Second Generation study now follows well over a thousand of the men's more than 2,000 children. When Waldinger gave his famous TED talk in 2015, about 60 of the original 724 men were still alive, most in their 90s.

The findings

Many of the men began adulthood believing that wealth, fame, and high achievement were the ingredients of a good life. The data, collected patiently over their entire lifetimes, told a different story. The clearest message from tens of thousands of pages of records is not about cholesterol or career — it is about people.

Close, warm relationships turned out to be better predictors of long, happy lives than social class, IQ, or even genes. Here is what the study keeps finding, in generation after generation.

“Loneliness kills. It's as powerful as smoking or alcoholism.”

In his words

Robert Waldinger — Harvard Medical School psychiatry professor, Zen priest, and the study's current director — has become the finding's most careful messenger. His 2015 TED talk, "What makes a good life?", has been watched tens of millions of times, and he is precise about what the data can and cannot say.

He notes that in surveys, most young adults name getting rich as a major life goal, and half add becoming famous. Then he sets that ambition against 85 years of actual lives: the men who invested only in work and achievement were, he says, among the saddest people in the study — and when the men looked back from their 80s, their most common regret was not having spent enough time with the people they cared about.

His prescription is deliberately small: lean into relationships. Replace some screen time with people time. Do something you enjoy alongside other people. Reach out — "Do a tiny little outreach," he says, every day.

“Good relationships keep us happier and healthier. Period.”

Why it matters here

Ask people in their 80s and 90s what mattered, and they rarely talk about job titles or square footage. They talk about the people — who stayed, who they loved, who sat with them when it was hard. The Harvard Study is what happens when science asks the same question with blood panels, brain scans, and 85 years of patience. It lands exactly where the elders land.

That agreement is the point. When a grandmother tells you to hold your friends close, that is one life's testimony. When 724 lives, tracked from youth to death, say the same thing in the data, testimony becomes evidence. The wisdom collected on this site and the longest study of adult life ever run are two roads up the same mountain — and they meet at the top, at other people.

“The key to healthy aging is relationships, relationships, relationships.”

Go deeper

Start with Waldinger's 13-minute TED talk — it is the study in miniature, told by the man who keeps it. Then read The Good Life (2023), where Waldinger and Marc Schulz turn the data into practice: social fitness, tiny outreaches, attention as the most valuable thing you own.

The study itself is still running. You can visit its official site, read the Harvard Gazette's coverage of the findings, and follow Waldinger's ongoing writing on living well.

We’ve distilled this source into principles to live by — each explained, applied to modern life, and linked back here.