Social Contagion: Having Fat Facebook Friends May Make You Gain Weight

January 2nd, 2009 by Nick Gonzalez

Apparently, pokes aren’t the only things that can be passed through social networks. A new article from New Scientist highlights social networking’s role in a phenomenon called “Social Contagion”.

The idea’s pretty simple; our moods and attributes are affected by those of our friends. You can “catch” a mood or quality in the same way you catch a cold. Emotions are contagion spread through our personal networks. This includes “happiness and depression, obesity, drinking and smoking habits, ill-health, the inclination to turn out and vote in elections, a taste for certain music or food, a preference for online privacy, even the tendency to attempt or think about suicide.”

Spreading Happiness

A study, released last month noted the phenomenon in the spread of happiness. In the report, Harvard medical sociologist Nicholas Christakis studied a network of several thousand friends, relatives, neighbors and work colleagues who participated in the Framingham Heart Study, an “ongoing multi-generational epidemiological survey that has tracked risk factors in cardiovascular disease among residents of Framingham, Massachusetts, since 1948.”

The study found that happy people not only tended to cluster together out of a natural affinity, but that happiness spread through social contact over time.

Moreover, happiness was not only influenced by the happiness of an immediate friend, but also friend’s friend, and their friend’s friend’s friend.

Here’s a list of the findings about how happiness spread:

• = May spread through empathetic mimicry or mirror neurological responses from seeing an emotion
• = Happy people tend to cluster
• = Happiness can spread through repeated contact
• = Happiness was not only influenced by the happiness of an immediate friend, but also friend’s friend, and their friend’s friend’s friend
• = Happiness increases the better connected you are to happy people, especially friends and family
• = Stonger relationships have a greater impact.
  • - “For example, if a good friend who lives within a couple of kilometres of you suddenly becomes happy, that increases the chances of you becoming happy by more than 60 per cent. In contrast, for a next-door neighbour the figure drops to about half that, and for a nearby sibling about half again. Surprisingly, a cohabiting partner makes a difference of less than 10 per cent, which coincides with another peculiar observation about some social epidemics: that they spread far more effectively via friends of the same gender.”

Spreading Obesity

While the theories on why happiness spreads rely heavily on phisical queues, such as empathetic mimicry or mirror neurological responses from seeing an emotion, the study of the spread of obesity hints there may be other ways for attributes to spread. It turns out that your risk of gaining weight increases significantly when your friends gain weight as well as friends of friends. The New York Times covered the study.

“Researchers found that an individual’s chances of becoming obese increased by 57 per cent if one of their friends became obese, 40 per cent if a sibling did and 37 per cent if their spouse did, irrespective of age (The New England Journal of Medicine, vol 357, p 370).”

Theories about the causal relationship for spreading obesity lie with social norms. The idea is that your idea of what an acceptable weight is changes when your real Facebook friends put on a few pounds.

Online Contagion

While neither of these studies have tackled social contagion within social networks, Professor David R. Bell of the Wharton School of Busienss studied the effect of word-of-mouth or other “social contagion” factors on consumer willingness to try an online retailer (link). The 2004 study used data provided by Netgrocer.com that spanned nearly 30,000 U.S. zip codes over the first 45 months of the online grocer’s business life.

Bell’s study found a significant impact, seeing a 50% increase in the base rate of consumers trying an online retailer’s services once they talked about or otherwise observed its use locally. Bell discovered this effect when he began plotting Netgrocer’s sales data on a map.

“What we saw was the thing spreading out like a disease. When we started to look at these patterns in more detail, what we found was that the new customers were not appearing randomly on the map. They were appearing in places that were contiguous to areas that already had customers.”

Sales for an online service that could be accessed anywhere, were clustering in geographic areas, hinting at word of mouth being the principal cause of new customers trying the service. Real world interactions were affecting online behavior. How the message was spread is unknown. Neighbors could have spotted a Netgrocer bag on a neighbor’s porch, or perhaps they chatted about it while passing on the street.

While the data included pre-social networking sales data from 1997-2001, Nicholas Christakis (who did the earlier study), is looking more deeply into how online behavior may impact people’s preferences. Christakis has been studying 1,700 juniors at an East Coast college. The study will monitor how friends profiles change over time, hinting out how influence spreads preferences through social networks. The study is ongoing and no data has been released.

The result of this study, and many others, will have a profound role in legitimizing what a lot of us in the web industry already know. Social media has profound impacts beyond zero order relationships between people and advertisements. Marketing’s impact resonates deeply through our social relationships beyond changing one person’s mind.

This entry was posted on Friday, January 2nd, 2009 at 4:38 pm and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.