Contagion

How often, when you visited the hospital over the past two weeks, were you asked to take temperature and wear mask? The answer, of course, is often, when everyone seems to be on high alert for human swine flu. If you still aren't convinced about the panic, go and read the posters put up in the hospital elevators: they are now teaching us the recipe - if there is one - which is called cough etiquette.

Regardless of the controversy over the need to quarantine people, most of us are afraid of anything that can spread like a bat out of hell. Swine flu, mad cow disease, severe acute respiratory syndrome, Hansen's disease... Omigod! The list of contagious possibilities is lengthy and, yes, horrifying.

Well, our tendency always is to get overly serious and paranoid, I must say. You're probably thinking that everything that spreads is bad, but it isn't. In fact, I have come across quite a number of good examples recently.

Investigators at Harvard Medical School, for instance, had documented in a part of the Framingham Health Study just how the smoking cessation by a friend or coworker spreads through close and distant social ties. Published in the New England Journal of Medicine, the study highlighted the network phenomena whereby groups of interconnected people stop smoking in concert.

This study dovetails with another "offspring cohort" of the Framingham Health Study, this time published in the British Medical Journal, reporting that happiness is contagious. When the scientists analysed the data looking for happiness trends, they found that happy people passed on their cheer to connected people they didn't personally know - and this transferred happiness lasted for up to a year.

To look for clusters of happy people in the social network, the same group of researchers are now studying happiness contagion in Facebook. Believe it or not, they noticed that people who smiled in their Facebook profile pictures tended to have other friends who smiled.

If you don't believe me, think about the old adage, "Laugh and the world laughs with you. Cry and you cry alone."