It’s the season to be wishing people happiness -- a happy Christmas for ordinary mortals, happy holidays for the PC brigade -- so what better time to produce a study showing how those wishes can be made effective? Not only family and friends, but even perfect strangers can get more than a passing buzz of pleasure if you take to heart the findings of American researchers Nicholas Christakis and James Fowler.

The pair revealed earlier this month that the old cliché, the “infectious laugh”, is actually quite scientific. They have come up with evidence that you can spread happiness not only to people close to you but to people two or three times removed from you whom you do not even know. “Laugh and the world laughs with you” may be an exaggeration, but there is more than a grain of truth in it.

Christakis, Professor of Sociology of the Harvard Medical School, and Fowler, Associate Professor of Political Science at the University of California, San Diego, specialise in “social contagion” research. Using the Framingham Heart Study -- a long-term study of people in a town in Massachusetts -- they have previously shown that obesity and quitting smoking are both socially contagious. Now they have analysed data on the emotional wellbeing of Framingham folk collected since 1983 and found that happiness, too, is catching.

It works like something like this. A writer who is discontented with drudging away for provincial papers, suddenly has an article published in the New York Times and becomes very happy. That lifts the chances of his wife, his friend living nearby, his sister -- also nearby, and his next door neighbours of becoming happier also. The neighbours, friends and siblings are then likely to make their friends happier, and those friends can even pass on the happiness bug to their friends.

Interestingly, the reverse is not the case: sadness does not spread through social networks as robustly as happiness. The study does not explain this phenomenon, but it is already a well-known fact: “Weep, and you weep alone.” It seems we have a natural immunity to the sadness bug, as well as a great susceptibility to good cheer.

Admittedly, the chances of cheering up become slighter with distance -- both geographical and relational -- from the source, and the effect diminishes over time, disappearing by one year. You need to keep sending out those happiness signals.

And here’s an odd thing: the people closest to you by natural or formal ties are not necessarily the ones to gain most from your burst of happiness. The data showed that next-door neighbours were 34 per cent more likely to become happy, a friend living within a mile 25 per cent more likely, siblings within one mile a 14 per cent chance -- and a spouse living in the same house only 8 per cent.

Daniel Kahneman, one of America’s leading happiness gurus, praised the research but said he could not believe that a spouse’s happiness had less impact than that of a next-door neighbour. Dr Christakis suggests it indicates that people take emotional cues from their own gender. But couldn’t it mean that friendship between spouses is not all it should be? Would it not give you a thrill to see your husband overjoyed, even if it was only because his team won the football?

Of course, passing stimuli like that are only a small part of the story of happiness. Your basic personality gives you either a flying start in the happiness stakes or something of a handicap to be overcome. After that, circumstances like health, marital status, employment and income (up to a certain level only) are important determinants of happiness.

Much research shows that family life provides the greatest source of satisfaction. Divorce -- as British children surveyed recently made clear -- is a source of misery. Being involved with others in the neighbourhood, workplace, community and church builds up “social capital” that correlates strongly with subjective wellbeing. In other words, happiness depends largely on the breadth and depth of one's relationships.

One thing that definitely does not increase happiness, according to two recent time use studies, is the very popular habit of blobbing out in front of the television for hours each day. ER and LA Law and Oprah may give you some passing pleasure at the end of what you consider a hard day at the office (but in reality was probably a slack day doing a job you don’t like), or daytime reruns of Baywatch may cheer you up for the space of the programme if you are unemployed, but afterwards you will be as dissatisfied as ever, say John P Robinson and Steven Martin. They found that cheerful people tend to spend more leisure time on reading, socialising and religious activities.

Daniel Kahneman and colleagues came to similar conclusions in their study: “engaging leisure and spiritual activities” such as visiting friends, exercising, attending church, listening to music… produced more enjoyment than any other group of activities. The researchers gently chided Americans for letting so much of their increased leisure time -- and potential for happiness -- over the past four decades go down the tube.

No Christmas is complete without an exchange of gifts, so one more piece of research may be worth mentioning. Experiments with more than 630 Americans showed that people were measurably happier when they spent money on others -- even if they thought that spending money on themselves would make them happier, and regardless of their income. Importantly, in these financially uncertain times, spending as little as $5 on someone else was enough to increase the giver’s happiness (if not the recipient’s). 
From all this a few conclusions about how to have a happy Christmas seem to follow:

* Forget yourself and engage with others -- first of all your own family, and then, perhaps, those neighbours and friends who most need your friendship.

* Don’t spend a lot of time watching television; read a book, listen to music or go fishing instead.

* Go to church and get in touch with the One who invented Christmas for the sole purpose of making us happy. Then you will have even more of it to spread around.

And do have a very merry Christmas -- the happiness of others may depend on it.

Carolyn Moynihan is deputy editor of MercatorNet.