Last Friday, I wrote a blog entry on an MSNBC report of recently published in the British Medical Journal on the contagion of happiness.  A few Methodist University colleagues have sent me links to other articles reporting on that study.  Dr. Steven Brey of the Philosophy and Religion Department saw a New York Times article, and librarian Arleen Fields found a CNN report.  There were a few interesting details in these studies.  For example, the NYT was more specific about the effects of distance: 

“A next-door neighbor’s joy increased one’s chance of being happy by 34 percent, but a neighbor down the block had no effect. A friend living half a mile away was good for a 42 percent bounce, but the effect was almost half that for a friend two miles away.” 

The only way to explain such a steep distance gradient is that face-to-face contact is necessary.  It must be that, like the flu, happiness can’t be caught over the phone or internet.   The NYT adds that only people in our social networks who have recently become happy will boost our happiness.  Those perpetually cheery people you’ve known a long time are old news and no longer give your mood a boost. The CNN report mentioned that size of one’s social network is also important.  Someone at the hub of a large network of people (meaning not just that one relates to lots of others but those others relate to one another, too) are more likely to become happy.   I guess that means Happiness Network it’s a good idea to introduce your friends to each other and do things as a group.

Finally, the CNN article had a nifty graphic of  the social network used in the study.  I’ve put their graphic to the right.  Yellow dots are happy people, blue are sad individuals, and green represents those in between.  It’s interesting that there are some large yellow clusters.  It looks like blue people sometimes cluster, but their groups are smaller and many of them seem scattered thoughout the yellow and green networks.  It’s a nice way to represent the study’s findings.

The orginal, and still most common definition of contagion is the spread of a disease from one individual to another.  Thus, the flu is contagious, and so is a cold.   The term has also been used by social scientists to refer to the spread of a behavior, belief, or emotion from individual to individual (or group to group) as a result of social influence.  Thus, economists have detected contagion in stock markets during financial panics and among nations in the expropriation of natural resources.  Political scientists have found evidence of contagion in acts as diverse as voting and suicide bombing.  And psychologists have found contagion effects for aggression and suicide.   

A study published today (reported here) has looked at the contagion of happiness.  James Fowler, a political scientist at the  University of California, San Diego, and Nicholas Christakis, a Harvard University medical sociologist, looked at changes in happiness over time in social networks.  They used data from the Framingham Heart Study, an ongoing cardiovascular study.  Participants in that study listed contact information for their closest friends, family members and neighbors, allowing the researchers to look at the spread in happiness from one person to the next.  When a  one person became happy, that person’s friend experienced a 25 percent increased chance of becoming happy.  A friend of that friend in turn was nearly 10 percent more likely to experience increased happiness, and a friend of that second friend had a 5.6 percent increased chance of happiness.  However, the effect was only found for friends who lived within a mile of each other; presumably the closer distance made for more contact and thus more opportunity for happiness to rub off.  Also, happiness contagion wasn’t found in the workplace, so an improved mood on the job doesn’t particularly affect the mood of coworkers. 

Despite the limitations of the contagion effect, it’s nice to know that, to some extent anyway, happiness is a characteristic of social systems, not just individuals.  For those of you who are guilt-prone, the downside to this conclusion would be that the happiness of others is in your hands.   Fortunately, one other finding of the study provides some consolation; unhappiness isn’t as contagious as happiness is.