Someone once told me, “Happy and successful people tend to be surrounded by other happy and successful people.” If we assume for a moment that it’s true, what are the implications? If you don’t find yourself in the company of people who are thriving, how are you supposed to get ahead?

1. Trade in your friends for new, better ones.
2. Keep your friends, but add a few higher-quality ones to raise the average.
3. Concentrate on what you can do to improve your own life.
4. Leverage your happiness and success by focusing on the well-being of the people around you.

A pair of social scientists, Nicholas Christakis and James Fowler, were interested in the question of whether happiness and health are truly contagious. Do they spread among people like an epidemic? In search of an answer, they borrowed a mountain of data from the Framingham Heart Study, a remarkable research project that followed the health and behavior of more than 15,000 subjects over the course of three generations and 50 years in and around Framingham, Massachusetts. Christakis and Fowler made a social-network map of about 5,000 subjects and analyzed data about obesity, smoking, weight loss, and happiness.

They concluded, among other things, that the increase in obesity in recent years is indeed an “epidemic.” If a Framingham resident became obese, his friends were 57 percent more likely to become obese, too. And the effect goes beyond first-order connections. It turns out that our behaviors have a rippling effect on our friends’ friends, and on their friends.

The study has its detractors. Some say that the researchers didn’t adequately control or correct for “homophily,” our tendency to seek connections with people who already share the same characteristics and behaviors.

As scientists love to say, “More research is needed.” But what do we have to lose by acting on the assumption that Christakis and Fowler are onto something?

Humans are intensely social, highly connected creatures. We model and mirror both good and bad behavior. We influence and are influenced by one another in myriad ways that we can’t see or don’t understand.

Want to be fit? Encourage your friends to get fit. Concerned about the health of your loved ones? Take good care of yourself. Searching for happiness? Seize opportunities to share “small moments of contagious happiness” far and wide!

Learn More

• Christakis and Fowler have written a book about their study’s findings, Connected.
• An article about the study (whence I borrowed the lovely phrase “small moments of contagious happiness”) appeared in The New York Times Magazine.
• Nicholas Christakis spoke at the February 2010 TED Conference. View a video of his presentation.

I wrote a draft blog post this morning about some social aspects of taking care of your health. I’m saving that one for another day, though, because I’d rather share the story of tonight’s trip to the park.

But when I’d walked about a mile, I ran into Gary, an old friend and a park fixture like myself. He was walking in the opposite direction, but when we met, he turned around and joined me. We walked together the rest of the way. I didn’t cut my walk short after all.

Three miles later, we got to talking about some of the other “frequent flyers.” We talked about the guy who ticks off his steps on his fingers and the strange fellow who sings and dances and jumps up on benches à la Fred Astaire. Gary said that he and his running buddies have given nicknames to a lot of the regulars. I’ve made up nicknames, too. We compared notes on Speedy (a.k.a. Tortilla), the Milk Man, Robot Girl, and many others. We also described familiar faces who’ve come to feel like friends over the years we’ve inhabited the park.

At that moment, I spotted a guy heading toward us whom I’d dubbed Inside-Edge Guy. He’s a sinewy, 50- or 60-something hispanic man who likes to run on the grass under the trees along the inside edge of the trail instead of on the trail itself. He and I have been on chatting terms every since the day he zigged when I zagged and we had to apologize for crashing into one another. When I saw him coming tonight, I held up my hand and yelled, “Hey, what’s your name?” He came over, and the three of us made introductions. (He never actually stopped, but jogged in place while he talked to us.) I’m glad that from now on, Inside-Edge Guy can be known by his real name, Joseph.

About a mile later, we encountered a young woman Gary knows from the gym. They hadn’t seen one another in a while, so she turned around, fell into step with us, and they set about catching up. For the rest of the walk, Lura, Gary, and I talked about walking, running, yoga, aikido, rowing, marathons, the park wildlife (two- and four-legged), and how much we enjoy the time we spend there.

Tonight’s thought:

You’re never doing this alone, even when you do it by yourself. There’s plenty of company in the struggle to get or remain healthy. You’ll find allies in the quest, companions for the journey. A shout out tonight to Gary, Lura, and Joseph for the pleasure of their company, and also to Damien, Xavier, Christian, and many other as-yet-nameless friends. Thanks for your smiles, waves, and silent encouragement.