The happiness equation

By Will Parker on December 8, 2008 in News

Happiness is not just an individual experience, but is dependent on the happiness of others to whom individuals are connected directly and indirectly, and requires close proximity to spread, suggests a fascinating new study in the British Medical Journal. Professor Nicholas Christakis from Harvard Medical School and Professor James Fowler from the University of California, San Diego, conducted the study to find out if happiness can spread from person to person and if clusters of happiness form within social networks.

Using data from the Framingham Heart Study, the researchers measured how social networks were correlated with reported happiness. They found that live-in partners who become happy increase the likelihood of their partner being happy by 8 percent, similar effects were seen for siblings who live close by (14 percent) and neighbors (34 percent). On average, every happy friend increases your own chance of being happy by 9 percent. Each unhappy friend decreases it by 7 percent. Interestingly, it was found that work colleagues did not affect happiness levels, suggesting that social context may curtail the spread of emotional states.

“One of the key determinants of human happiness is the happiness of others,” said Christakis. “An innovative feature of our work was exploring the idea that emotions are a collective phenomenon and not just an individual one.” The researchers say the relationship between people’s happiness can extend up to three degrees of separation (to the friend of one’s friends’ friend), and that people who are surrounded by happy people are likely to become happy in the future.

Apparently, close physical proximity is essential for happiness to spread. A person is 42 percent more likely to be happy if a friend who lives less than half a mile away becomes happy, the effect is only 22 percent for friends who live two miles away, and this effect declines at greater distances. The findings suggest that clusters of happiness result from the spread of happiness and not just a tendency for people to associate with similar individuals.

Similar effects are seen in siblings who live within a mile and in co-resident spouses versus distant siblings and distant spouses. Next-door neighbors have a significant effect, 34 percent, while neighbors further away, even on the same block, do not. “We think the spread of emotion has a fundamental psychobiological aspect,” said Christakis. “Physical personal interaction is necessary, so the effect decays with distance.”

There are several practical implications to the work, not least of which, Fowler said, might be to take greater responsibility for your own happiness because it affects dozens of others. “The pursuit of happiness is not a solitary goal. We are connected, and so is our joy.”