Happiness is Contagious

Yawn. Just seeing that word made you more likely to open your mouth in a big inhalation, contort your face and stretch out your arms. In other words, yawning is a contagious experience.

Now it turns out that happiness is like a yawn: it easily spreads between people in social networks. Nicholas Christakis, a doctor/sociologist at Harvard, is doing some of the most interesting work on social networks - he's shown, for instance, that when a loved one gets ill people suffer serious medical consequences, and that the ability to quit smoking depends in large part on the number of smokers in your social circle - and his new paper looks at how happiness ripples through even remote human interactions.

While there are many determinants of happiness, whether an individual is happy also depends on whether others in the individual's social network are happy. Happy people tend to be located in the centre of their local social networks and in large clusters of other happy people.

The happiness of an individual is associated with the happiness of people up to three degrees removed in the social network. Happiness, in other words, is not merely a function of individual experience or individual choice but is also a property of groups of people.

Indeed, changes in individual happiness can ripple through social networks and generate large scale structure in the network, giving rise to clusters of happy and unhappy individuals. These results are even more remarkable considering that happiness requires close physical proximity to spread and that the effect decays over time.

Our results are consistent with previous work on the evolutionary basis of human emotions and with work focusing on the fleeting direct spread of emotions. In addition to their internal and psychological relevance, emotions have a specifically social role: when humans experience emotions, they tend to show them. Like laughter and smiling, the emotion of happiness might serve the evolutionarily adaptive purpose of enhancing social bonds.

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Thanks for sharing this fascinating research! So much of the time we think we're the ones directly responsible for happiness/unhappiness, but it's mildly unsettling to see how strongly other people's emotions can affect our own.

I must admit I have not read the paper carefully, but I can't see how causation (happy friends make you happier) could be inferred from simple correlation (happy people tend to be friends with other happy people). Couldn't it be that alike personality types attract each other, so melancholy people would have other melancholics as friends? As for happiness "waves", they could be explained by external influences (for example, local events).

To really get in the holiday spirit, go see the movie Synecdoche, NY. The word synecdoche was featured in William Safire's NYT Sunday Magazine column today though he did not like the movie. I had to see it three times before it brought a smile to my lips and tears to my eyes.

Jonah, what role do mirror neurons play in yawning and to what level do you think aspects of the amygdala and/or mirror neurons play in the contagious nature of emotions?

Is not this "synthetic happiness" or a case of Robert K. Merton´s "Mathew effect"

I mean, happiness is not really experience as an outcome of one´s own healthy state, achievements or pleasant states, but happiness because others are happy.

"happiness requires close physical proximity to spread and that the effect decays over time."
If we take this fact to be true, it makes perfect sense in relationships.
People in relationships can be so happy or sad depending on the other person in the couple. The proximity of their relationship causes them to so incredibly effect the other. The extreme happiness (love) one may feel can cause the other to feel similar feelings solely because of the rub off effect and not necessarily because of their own desires. This is why people are so drawn to and happy with receiving any positive attention. Lots of happiness directed towards you rubs off on you and causes you to become attracted in a search for more happiness to the person giving you the attention.