It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
For me, this story begins about 15 years ago, when I was a hospice doctor at the University of Chicago. And I was taking care of people who were dying, and their families, in the South Side of Chicago. And I was observing what happened to people and their families over the course of their terminal illness. And in my lab,
I was studying the widower effect, which is a very old idea in the social sciences, going back 150 years, known as "dying of a broken heart." So, when I die, my wife's risk of death can double, for instance, in the first year. And I had gone to take care of one particular patient, a woman who was dying of dementia. And, in this case, unlike this couple, she was being cared for by her daughter. And the daughter was exhausted from caring for her mother.
And the daughter's husband, he also was sick from his wife's exhaustion. And I was driving home one day, and I get a phone call from the husband's friend, calling me because he was depressed about what was happening to his friend. So here I get this call from this random guy that's having an experience that's being influenced by people at some social distance.
And so I suddenly realized two very simple things. First, the widowhood effect was not restricted to husbands and wives. And second, it was not restricted to pairs of people. And I started to see the world in a whole new way, like pairs of people connected to each other.
And then I realized that these individuals would be connected into foursomes with other pairs of people nearby. And then, in fact, these people were embedded in other sorts of relationships, marriage and spousal and friendship and other sorts of ties. And that, in fact, these connections were vast, and that we were all embedded in this broad set of connections with each other. So I started to see the world in a completely new way, and I became obsessed with this.
I became obsessed with how it might be that we're embedded in these social networks, and how they effect our lives. So, social networks are these intricate things of beauty, and they're so elaborate and so complex and so ubiquitous, in fact, that one has to ask what purpose they serve. Why are we embedded in social networks? I mean, how do they form? How do they operate? And how do they effect us?
And so my first topic, with respect to this, was not death, but obesity. And suddenly it had become trendy to speak about the "obesity epidemic." And, along with my collaborator, James Fowler, we began to wonder whether obesity really was epidemic, and could it spread from person to person like the four people I discussed earlier. So this is a slide of some of our initial results. It's 2,200 people in the year 2000. Every dot is a person. We make the dot size proportional to people's body size. So bigger dots are bigger people. In addition, if your body size, if your BMI, your body mass index is above 30, if you're clinically obese, we also colored the dots yellow.
So, if you look at this image, right away you might be able to see that there are clusters of obese and non-obese people in the image. But the visual complexity is still very high. It's not obvious exactly what's going on. In addition, some questions are immediately raised. How much clustering is there? Is there more clustering than would be due to chance alone? How big are the clusters? How far do they reach? And, most importantly, what causes the clusters?
So we did some mathematics to study the size of these clusters. This here shows, on the Y-axis, the increase in the probability that a person is obese, given that a social contact of theirs is obese. And on the X-axis, the degrees of separation between the two people. And on the far left, you see the purple [bar].
It says that, if your friends are obese, your risk of obesity is 45 percent higher. And the next bar over, the [red bar], says that, if your friend's friends are obese, your risk of obesity is 25 percent higher. And then the next [bar] over says that, if your friend's friend's friend, someone you probably don't even know, is obese, your risk of obesity is 10 percent higher. And it's only when you get to your friend's friend's friend's friends, that there's no longer a relationship between that person's body size and your own body size.
Well, what might be causing this clustering? There are at least three possibilities. One possibility is that, as I gain weight, it causes you to gain weight, a kind of induction, a kind of spread from person to person. Another possibility, very obvious, is homophily, or "birds of a feather flock together."
Here, I form my tie to you because you and I share a similar body size. And the last possibility is what is known as confounding, because it confounds our ability to figure out what's going on. And here, the idea is not that my weight gain is causing your weight gain, nor that I preferentially form a tie with you because you and I share the same body size, but rather that we share a common exposure to something, like a health club, that makes us both lose weight at the same time.
And when we studied these data, we found evidence for all of these things, including for induction. And we found that, if your friend becomes obese, it increases your risk of obesity by about 57 percent in the same given time period.
There can be many mechanisms for this effect. One possibility is that your friends say to you something like -- you know, they adopt a behavior that spreads to you -- like, they say, "Let's go have muffins and beer," which is a terrible combination. But you adopt that combination, and then you start gaining weight like them. Another more subtle possibility is that they start gaining weight, and it changes your ideas of what an acceptable body size is. Here, what's spreading from person to person is not a behavior, but rather a norm. An idea is spreading.
Originally posted by bringthelight
Pretty cool stuff. I always thought of happiness being contagious and this guy proved it. With all the social media today the world is becoming more and more connected. It will be interesting to see the property cange that comes with the new structure. Maybe we go from graphite to diamond!