Earlier this month, the British Medical Journal published a study on happiness. The study is from the same stable of researchers who have showed how social relationships affect weight gain, smoking, and exercise. Using data from the ongoing Framingham Heart Study, they show how personal relationships affect happiness and how it spreads through a social network.

In a nutshell, four things characterize the spread of happiness: the type of relationship is the most important; but second, the geographic distance between people is also important; the effect of happiness degrades with time; and happiness reaches out beyond the immediate relationship.

In fact, happiness extends to three degrees of separation—that is, my happiness can affect the friend of a friend’s friend and the happiness of the friend of a friend’s friend can affect me.

But what the researchers saw was that as the time increased between surveys of participants, the effect of someone’s happiness during one period decreased dramatically after 2½ years. However, it didn’t decrease to zero. An echo of happiness remained.

In their earlier study of weight gain, these researchers found that proximity of friends and relatives had no effect. What mattered was the relationship. In this study, both were very important. For example, the happiness of a next-door neighbor was the second most power influence on someone’s own happiness, while the happiness of a neighbor who was further away but on the same block had virtually no effect at all.

More powerful than happy next-door neighbors were happy friends who lived within a mile of each other—twice as powerful. The relationships that had no effect on happiness, in addition to neighbors further away on the same block, were friends and siblings living more than a mile away, spouses living apart, and co-workers. In between were siblings living within a mile of each other and spouses living together.

I think this body of research speaks powerfully to how we humans read and take our cues from each other. In this case, we are reassured by the happiness of people we are close to, emotionally and geographically. Biologically, this makes a lot sense to me. The lesson here seems to be: move into a neighborhood with your friends.

Unfortunately, this study is naïve in its way. We don’t know what effect social class or income had on the susceptibility of study participants for happiness. I recall an ’80s rock star saying, “Money can’t buy happiness, but you can park your yacht right up next to it.”

It turns out that there’s a fair amount of research to support the claim that increased income in fact doesn’t have much of an effect on happiness—at least in so far as that income enables the purchase of more stuff. A recent article in Science reported on a study that found that, above the subsistence level, total income had an inconsistently weak effect on happiness. What really affected happiness was spending on gifts for other people and donating to charities—what the researchers called pro-social spending. Personal spending (expenses, housing, and products for personal use) had no effect on happiness—none.

Not that anyone should be surprised, but this supports the idea that Gross National Product is a ridiculous measure of our national welfare. The San Francisco Chronicle carried a story earlier this month about the Himalayan nation of Bhutan and its development of Gross National Happiness as its measure of national welfare. The occasion was a conference on GNH that attracted a wide range of economic officials, including many from Europe.

The government of Bhutan is developing an index for GNH. Unlike GNP, which is measured in dollars, Bhutan’s GNH index is said to have 72 standards that include equitable distribution of income, sustainable development, environmental protection, conservation of cultures and natural resources, and good government. Next year, France will unveil its version.

I’d be irresponsible if I did not also mention that several days after the Chronicle carried this news, it carried a story about citizens of Bhutan who are ethnic Nepalese made refugees by the government of Bhutan in the early 1990s. Many are being brought to the United States as a new wave of grateful immigrant workers. I don’t know the whole story here, but it reminds me that nothing’s perfect. Congratulations, President-elect Obama.

The network researchers open their article by saying that “happiness, like health, [is] a collective phenomenon.” So move into a neighborhood with your friends and take some pro-social actions. It adds to Gross National Happiness as well as your own.