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Aditi Nerurkar, MD Headshot

Social Contagion: Are Your Friends' Habits Rubbing Off On You?

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SOCIAL CONTAGION

Birds of a feather... peas in a pod... one rotten apple. As children, we were given many examples -- be they avian, vegetable or fruit -- of how the company we keep might influence us. Emerging research has found that these childhood lessons weren't mere scare tactics employed by our well-intentioned parents. They were onto something.

It turns out that unlikely things like happiness, obesity and smoking are contagious, say Nicholas Christakis and James Fowler, two researchers who study the science of human networks. They call these phenomena social contagion and have published their findings in the book "Connected." "The basic idea is that because people are connected, their health is connected. This is highly relevant to a host of health phenomena," explains Christakis.

With our predilection for engaging in activities of daily life (like eating and exercise) with loved ones, this isn't all that astonishing. The sympathy weight gained by spouses during pregnancy is a common example. But according to Christakis and Fowler, we are not simply influenced by those in our immediate surroundings. The ripples of our health behaviors travel much farther than anyone might expect. Just how far? Christakis and Fowler claim that we are influenced by our friend's friend's friend -- even if we've never met. Christakis says this is because "[we] humans are part of a superorganism. There's an expression of collective social properties in human networks that arise because of the connections between people." To me, this sounds eerily reminiscent of Morpheus and Neo's world -- The Matrix: Medically Reloaded.

Given Christakis and Fowler's findings, it's tempting to add "social network" to our lengthy list of excuses preventing us from living as healthfully as we ought to. But, cautions Christakis, "[it] works both ways. While you are affected by people, you also affect people. When you make a positive change in your life, you don't just benefit yourself or even your friends and family, you benefit dozens, perhaps hundreds, sometimes thousands of people who you don't know directly but who are in some way connected to you."

And if being happier, slimmer and smoke-free weren't beneficial enough, social networks have also been implicated in a longer life, says National Geographic writer and explorer Dan Buettner. In his book "The Blue Zones," Buettner visited areas of the planet with the highest concentration of healthy centenarians (people over the age of 100). These were Italy's Sardinia, Costa Rica's Nicoya Peninsula, Japan's Okinawa and Loma Linda in California. In each of these places, social networks were a key ingredient in the recipe for human longevity. As one elderly Okinawan told Buettner, "Chatting with my maoi [a group of lifelong friends] is my ikigai [the reason for waking up in the morning]. It's much easier to go through life knowing there is a safety net."

With the conclusions of Christakis, Fowler and Buettner, we are left to ponder how our own social networks measure up. Are they promoting or preventing our health and well-being? Must we all aspire to befriend Lance Armstrong or relocate to a Blue Zone to live happier, healthier and longer lives? "Its not so simple," says Christakis. "Any benefit you get by cutting a tie with your friend who isn't healthy is potentially countermanded by the cost of losing a friend. The reason we form social networks is because the benefits of a connected life outweigh the cost. But to benefit from these connections, we expose ourselves to certain risks. It's the price we pay for the spread of ideas."

There's been an audible buzz around social networks in recent months -- from places as disparate as Hollywood's Kodak Theater to Cairo's Tahrir Square. And it might seem like social connectedness is a product of modern innovation, but it's downright ancient. In Buddhism, human interconnectedness is described through the allegory of Indra's Net: a jeweled net where each jewel, representing one individual, is linked to all other jewels by a complex weaving structure -- "bling" in its purest form. Paradoxically, this timeless Buddhist net lends itself to an easy comparison with our own net of human society: the Internet.

But in a world where 2-D screen time often trumps 3-D face time, the interdependence of humankind is a tough sell. I wonder how we can leverage our connectedness, in this puzzling conundrum of technological inclusion and social seclusion, to improve our health and well-being? Is our most poignant opportunity to experience a deep-felt sense of our shared humanness relegated to global catastrophes, most recently, when a distant radioactive plume from a quaking ring of fire threatened to tickle our American shores? And doesn't the very nature of our interconnectedness deserve a less tragic and more benevolent cue?

I hope, somewhere in the blue zone of Okinawa, a wise elder sits serenely amongst friends, with these answers.

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