An article by Clive Thompson in Sunday’s New York Times Magazine asks, “Is Happiness Catching?” Researchers Nicholas Christakis and James Fowler wondered whether certain human behaviors are “contagious.” We talk about various social changes spreading like epidemics, though that’s often the case of a metaphor turning into a meme without stopping to fact-check.

…The truth is, scientists have never successfully demonstrated that this is really how the world works. None of the case studies directly observed the contagion process in action. They were reverse-engineered later, with sociologists or marketers conducting interviews to try and reconstruct who told whom about what….Despite our pop-cultural faith in social contagion, no one really knew how it worked.

Christakis and Fowler used data from the long-term Framingham Heart Studym including sheets  on which participants named one friend likely know where the participant would be in four years (to help researchers continue following up).

The article’s well worth reading; this is my oversimplification.  Christakis and Fowler studied 5,124 subjects connected in 53,228 ways over 32 years.  When someone became obese, friends were 57% more likely to, as well.  “And a Framingham resident was roughly 20% more likely to become obese if the friend of a friend became obese–even if the onnecting friend didn’t gain a pound.”

The researchers hypothesize that certain behaviors spread through subconscious social signals.  Those signals become cues about what’s acceptable–smoking, eating large portions, things like that.  They also found that he happiest people in the Framingham study were those who had the most connections, even if the relationships weren’t necessarily deep ones.

That’s because (they believe) happiness doesn’t come only from having deep relationships; it can result from having frequent, small moments of happiness.

What I found interesting is that different “contagions” spread in different ways.  Co-workers don’t spread happiness to one another, while personal friends do.  (Co-workers have a much greater effect on smoking.)

In terms of weight control, your spouse doesn’t have much effect on your behavior.  The researchers suggest that our body-image models are people of the same sex.  If your same-sex friends gain weight, you’re more likely to.

Clearly, I need to have more male friends who are fit.  Or, if you know me, then you need to have them, for my sake.

Christakis and Fowler’s strangest finding is the idea that a behavior can skip lines–spreading to a friend of a friend without affecting the person who connects them….

The two researchers say they don’t know for sure how the link-jumping works.  But they theorize that people may be able to pass along a social signal without themselves acting on it.

For example, if your work friends become obese, you may become more tolerant of obesity and unconsciously influence family members who “then feel a sort of permission” to gain weight.

Thompson presents some critiques of this approach–one possibility is “homophily,” the flocking together of birds of a feather.  Another is the possibility that the local environment (like Framingham itself) influences the behavior, rather than the other people.  And the Framingham data included one non-family friend, which could distort the influence of the people named.

Christakis and Fowler mention what they call directionality–the type of friendship.  If Art says Jamal is a close friend, but Jamal doesn’t see Art that way, then Art’s weight gain has little impact on Jamal, whereas Jamal’s is likely to have much more on Art.

A couple of interesting patterns: when it comes to smoking, the social shift in its acceptability means that, on the one hand, we rarely encounter smokers at work or in public.  On the other hand, smokers have formed smaller, tighter networks with high percentages of smokers–the people who collect outside the office building, the people who rendezvous in the bar that still permits smoking.  Thus they have fewer contacts with people from whom they can “catch” nonsmoking behavior.

The other pattern?  The use of social networks like Facebook to widen the community of connections a person has, especially for making some improvement.

In theory, the best way to fight obesity [according to this model] isn’t to urge people to diet with a cluster of close friends.  It is to encourage them to skip a link and to diet with friends of friends.  That way, in your immediate social network, everyone is surrounded on at least one side by people who are actively losing weight, and this would in turn influence those other links to begin losing weight themselves.

Sounds great: get a weight-loss widget for Facebook, and maybe cut your ties to people with bad behavior.  (But isn’t that what the smokers have in effect done?)

A final suggestion of the study is that at least some of our influence may be partly innate.  “Your level of connectedness,” says Thompson, appears to be more persistent than even your overall temperament.”

In other words, if you tend to have lots of friends and make lots of connections, you’re likely to continue to do so, even if you switch to a completely new environment.  And those will remain even if your level of happiness declines–you’ll be less happy, but you won’t become an isolate.

I’m intrigued by this.  I don’t see myself as having a lot of close connections, but I’ve found myself making more connections in recent years, thanks in part to social networks.  And I know I’m prone to one-to-one exchanges.  It’s situational, at least for me–I place great value on being able to spend a lot of time with just one person, but on a day-to-day basis that simply doesn’t happen.  Shorter conversations or mini-exchanges (by phone, by instant message, by back-and-forth blog comments, or on Twitter) can and do energize me.

I’m not quite ready to post a widget telling these people how much weight I’d like to lose in the next three months, though.  I guess I need a bit more faith in the friend-of-a-friend model.

CC-licensed images:
Friends of Art by BlackHawkTraffic.
Circles and influence by Jeff Kubina.