Social Networks

I've got a new essay on social networks and the research of Nicholas Christakis and James Fowler in the latest issue of Wired:

There's something strange about watching life unfold as a social network. It's easy to forget that every link is a human relationship and every circle a waistline. The messy melodrama of life--all the failed diets and fading friendships--becomes a sterile cartoon.

But that's exactly the point. All that drama obscures a profound truth about human society. By studying Framingham as an interconnected network rather than a mass of individuals, Christakis and Fowler made a remarkable discovery: Obesity spread like a virus. Weight gain had a stunning infection rate. If one person became obese, the likelihood that his friend would follow suit increased by 171 percent. (This means that the network is far more predictive of obesity than the presence of genes associated with the condition.) By the time the animation is finished, the screen is full of swollen yellow beads, like blobs of fat on the surface of chicken soup.

The data exposed not only the contagious nature of obesity but the power of social networks to influence individual behavior. This effect extends over great distances--a fact revealed by tracking original subjects who moved away from Framingham. "Your friends who live far away have just as big an impact on your behavior as friends who live next door," Fowler says. "Think about it this way: Even if you see a friend only once a year, that friend will still change your sense of what's appropriate. And that new norm will influence what you do." An obese sibling hundreds of miles away can cause us to eat more. The individual is a romantic myth; indeed, no man is an island.

Wired also has a series of beautiful images of the actual network data. And if you'd like to learn more about the research, I highly recommend the new book by Christakis and Fowler, Connected. And here's a much longer article on the social network research by Clive Thompson, which does an excellent job of explaining the different ways in which the scientists try to separate causation from correlation. (Is obesity really contagious? Or did a McDonald's just open up in the neighborhood?) It turns out that the old warning of David Hume - causation is a slippery concept and a tricky thing to prove - is even more relevant in the age of excess data, when supercomputers can sift through terabytes of social information and uncover all sorts of fallacious correlations. Christakis and Fowler get around this problem through some clever analytics: they show, for instance, that obesity is much more contagious between close friends than it is between acquaintances, which suggests that social networks are the driving mechanism (and that the new neighborhood McDonald's isn't). Regardless, it will be interesting to watch this new field evolve in the next few years, as the Humean skeptics do battle with the enthusiastic believers...


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I usually think of 'contagious' as in relation to infectious disease and not social networks, interesting stuff.

It'd be interesting to see prospective data on this or some explanation or further evidence of what they call the subconscious forces that are at work in these social networks.

As someone who has inherited the ability to store food from my freezing and starving ancestors, and look like my working class ancestors, I am more than a little sick of being treated like a diseased pariah. Seems to me that the moral panic and class discrimination in hating fat people is the only form of "ism" that is allowed nowadays, and people discriminate gleefully and with a sense of moral self-righteousness.

By David Kerlick (not verified) on 13 Sep 2009 #permalink

Social networks lead to obesity? I think it points more toward unhappiness, eating to feel some kind of happiness. If not eating, drinking or drugs. Unable to compete in this advertising nightmare , one falls back to finding any kind of happiness they can when they feel they don't add up to ideals shown in this 24/7 ad world.

@Was Once:

Maybe depression is then contagious? :)

As a developer of social applications, I can totally understand this. I have to design things that I know when one person gets it, that will influence their friends to also use it. It's difficult to do well, but is an easy thing to do.

We behave according to what we expect from ourselves, these expectations in turn having been based on what our contacts with others lead us to expect. Which we can expect will make things extremely complicated.

I think that among the problems is:

The culture we are living in has no inherent meaning, and no dialogue with nature, If we are fortunate, we may have an ocean retreat from the man-made. If we are less affluent we may make special trips to connect to nature, be it at the zoo, or the botanical gardens. But for most of us nature is absent from our daily life. This includes our relations with our own bodies.

For more details about it check the post and its interesting comments:…

Whoa. Take it closer to the neuron. We behave largely out of neural habit, maybe 10% is newly triggered. So. Friends = familiarity, which magnetizes brain activity. I see flocks of birds flying in sync. (And I shudder at the marketing implications. I don't know whether to run to apply this or leap to suppress it.) Friends also tend to be emotionally based in the brain, which makes the influence much stronger.
Thanks for the impressions. By the way, I lost twelve pounds recently.
Suzanna Stinnett / Cloud Alchemy

Wouldn't some of this also be an aspect of cohorts: My friends are like me and we tend do go through the same life stages at about the same time?

Something is to be said about all of us lemmings (a myth, I know) leaping off of a Western Bacon Cheeseburger at the same time...

By Big and Tall, … (not verified) on 15 Sep 2009 #permalink

Is this an exploration on the effect of social networks on shaping one's sense of social norms, simply expressed in an analysis of the spread of obesity (perhaps I need to read the article in Wired to get the full context)? Can this be extended to other areas as well, such as media consumption? Does the social network effect influence the tendency for people to gravitate to news sources that confirm their inherent biases?

As far as I can see anything leads to obesity recently,it is like whole world is getting fat.But I don't think you can blame facebook for that.Instant pleasure wins over long time plans most of the time and kills us eventually.We need to think and move.

I totally agree with this claim.If five of your best friends are millionare you will be a millionare one day if you are not already.If you spend most of your time with obese people you will probably be obese one day if you are not already.