What makes life beautiful?

What keeps us healthy and happy throughout life? What would you focus on to invest in your future now? A new research polled millennials (born 1980–1999) about their top life aspirations. Over 80% indicated wealth was their top life objective. Famousness was the second most important life goal for 50% of young adults.

Work, strive, and achieve more are always encouraged. We believe we must pursue such things to live well. Understanding people's lives, decisions, and outcomes is nearly difficult.

We learn most about human life by asking individuals to remember the past, and we know that only living gives us experiences. Most things we do in life are forgotten, and memory may be creative.

What if we could follow our lives from youth to old age to see what makes individuals happy and healthy?

We did. The Harvard Study of Adult Development may be the longest-running adult life study. Each year spanning 75 years, we asked 724 men about their employment, home life, and health, unaware of their personal experiences.

This type of research is rare. Most such programs fail within a decade because many individuals drop out, research funding is curtailed, academics get distracted, or die, and no one wants to restart.

However, serendipity and generations of scholars have kept the study going. About 60 of our initial 724 guys are still living and participating, many in their 90s. More than 2,000 of their offspring are being studied. The fourth study director is myself.

Two groups of men have been followed since 1938. The first group began research as Harvard College sophomores. All of them graduated college during WWII, and most served in the military.

Second, we tracked a group of males from Boston's poorest neighbourhoods, chosen for the study because they came from some of the city's most problematic and disadvantaged families in the 1930s. Many of them lived in shantytowns without hot or cold water.

All of these youth were interviewed for the study. They were checked. We interviewed their parents at home. All kinds of grownups emerged from these youth. Some became factory owners, lawyers, bricklayers, doctors, and US presidents.

Some became alcoholics. Some developed schizophrenia. Ascending the ladder was one option, but others did the opposite.

The founders of this study never thought that I would be standing here 75 years later telling you it is still ongoing. Our attentive and dedicated research staff calls our subjects every two years to ask about their lives again.

To get a better understanding of these lives, we don't just survey them. We meet them where they live. We get their medical history from their doctors. We do blood tests, brain scans, and talk to their children.

We videotape them discussing their deepest concerns with their spouses. About a decade ago, when we finally asked the spouses if they would join us as members of the study, most of the women said, "It seems like it's time."

So what have we learned? What are the lessons learned from the tens of thousands of pages of information we’ve unearthed from these lives ? They’re not about wealth, fame, or hard work. The clearest message from 75 years of research is this: Good relationships keep us happier and healthier. That’s it.