What keeps us happy and healthy through life? If you knew the answer, would it change where you put your time and energy to create your future best self? A recent survey of millennials asking them their life goals, more than 80% said to get rich. What if we could watch entire lives unfold through time to determine what really matters to keep people happy and healthy? Well, the Harvard Study of Adult Development did exactly that.

The longest study of its kind, the Harvard Study of Adult Development tracked 724 men year after year asking about their lives, not knowing how their stories would turn out. Studies like this are exceeding rare. Almost all projects fall apart within a decade due to people dropping out, lack of funding, or research directors moving on or passing away. Through a combination of luck and persistence this study has survived. Dr. Robert Waldinger is the fourth director of the study and recently gave a TED talk on his findings.

The study tracked two groups of men, beginning in 1938. Half of the men were sophomores at Harvard and the other half (of the same age) came from the most impoverished sections of Boston. Over the years, many of the men from impoverished Boston, asked, “Why do you keep studying me, my life is not that interesting.” The Harvard men never asked that question…?

There were three main conclusions from the study.

First, social connections are good for us. In fact, the study found that loneliness literally kills us. The men with strong social connections to family, friends, and community were happier, healthier and lived longer lives. Those with weaker connections had more health declines in middle life and lived shorter lives.

The second big learning was about quality of relationships. It was not the number of friends these men had, but the quality of the closest relationships that mattered. Living in conflict is bad for our health. Living amid good, strong relationships is protective. Studying people in their 80’s and 90’s and looking back at them at age 50, the study could see that the greatest predictor of mortality was not cholesterol level. Waldinger and his colleagues found, “The people who were most satisfied in their relationships at age 50 were the healthiest at age 80.”

The third learning was that good relationships don’t just protect our body, they also protect the brain. Those in securely attached relationships in their 80’s had sharper memories. Men in relationships where they really can’t count on their partner, experienced earlier memory decline.

Now, some may say this wisdom is old as the hills. So why do millennials – and people of all ages – seek fame and fortune as the keys to happiness? As humans we are all fallible and can revert to pure self-interest. There’s sweet irony in the knowledge that consistently doing what’s best for others ends up being what’s best for yourself as well. Hug your family tonight and tell them that you love them. Reach out to that challenging relationship at work and show grace. Give more than you receive – and remember that grudges hurt the one holding the grudge far more than the other. Maybe there is something to the notion of live, laugh and love.

Oh, and if you want to lead a long happy heathy life, don’t go to Harvard!