Contagious happiness?

Are we so hungry for meaning in our chaotic world, that mere association is automatically assumed to be proof of a cause and effect relationship? Again and again, the media seizes upon research results (sometimes with the eager cooperation of the researchers) and touts them as proof that A causes B.

Latest in this parade of dubious connexions is the study which found that happy people tend to know a lot of other happy people, and the more happy people in your circles of acquaintance, the happier you are. Ergo, knowing happy people makes you happier!

An article about the study says:

The scientists found that a person’s happiness is most likely to boost the happiness levels in people closest to him — spouses, relatives, neighbors, and friends.

But, if one person is happy, that increases the chances of happiness in a friend living within a mile by 25 percent. The “cascade” effect, as the researchers put it, continues: a friend of the friend has almost a 10 percent higher likelihood of being happy, and a friend of that friend has a 5.6 percent increased chance.

In the other words, one person’s happiness can spread outward through three degrees of separation. Those at the center of such circles may be people that “you have never met. But their mood can have a profound effect on your own mood,” Fowler said.


Fig 1 Happiness clusters in the Framingham social network. Graphs show largest component of friends, spouses, and siblings at exam 6 (centred on year 1996, showing 1181 individuals) and exam 7 (year 2000, showing 1020 individuals). Each node represents one person (circles are female, squares are male). Lines between nodes indicate relationship (black for siblings, red for friends and spouses). Node colour denotes mean happiness of ego [individual being studied] and all directly connected (distance 1) alters [alters are persons connected to the ego, potentially influencing the behaviour of the ego], with blue shades indicating least happy and yellow shades indicating most happy (shades of green are intermediate).

Figure (reduced here) and caption are from the full article, in the British Medical Journal.

The original article’s abstract says in part,

Results Clusters of happy and unhappy people are visible in the network, and the relationship between people’s happiness extends up to three degrees of separation (for example, to the friends of one’s friends’ friends). People who are surrounded by many happy people and those who are central in the network are more likely to become happy in the future. Longitudinal statistical models suggest that clusters of happiness result from the spread of happiness and not just a tendency for people to associate with similar individuals. A friend who lives within a mile (about 1.6 km) and who becomes happy increases the probability that a person is happy by 25% (95% confidence interval 1% to 57%). Similar effects are seen in coresident spouses (8%, 0.2% to 16%), siblings who live within a mile (14%, 1% to 28%), and next door neighbours (34%, 7% to 70%). Effects are not seen between coworkers. The effect decays with time and with geographical separation.

Conclusions People’s happiness depends on the happiness of others with whom they are connected. This provides further justification for seeing happiness, like health, as a collective phenomenon.

So that’s clear: happiness is somehow “contagious”! By this line of reasoning, we could investigate the contagious effects of race, profession, sports fanaticism, and most anything else. I must have become white (and stayed that way) because nearly all my friends are white; a lawyer is a lawyer because he or she knows so many lawyers, and so on.

On a certain level, I have no argument with the direct “contagiousness” of positive emotion: it certainly cheers one up to be around smiling ebullient people. I still remember a dark rainy day, decades ago, when I was walking gloomily across my college campus and passed someone smiling and carrying a bright bouquet of flowers. It actually did change my mood, I smiled back and was bumped out of my self-absorbed thoughts. But then, the same effect might well have resulted from other stimuli that are enjoyable to me: seeing a horse running in a field, reading something that introduced a new idea, even coming in out of the rain into a warm inviting place. And if I do things often enough that elevate my mood, I will probably be in fact be happier than if I do the opposite: but these are choices, not influences beyond my control.

When it comes to a person’s close associates, surely Pollyanna chooses to hang around mostly with other cheerful folks, rather than letting Cassandra or Gloomy Gus bring her down. Perhaps really unhappy people are hard to be around and don’t share the interests and types of conversations that are common to happy people. Some people have truly terrible experiences dealt them by fate, and are unhappy; with others you feel like a good kick in the pants to get them out of being so self-centered would go along way toward changing their mood; either way, it seems entirely reasonable that the positive happy busy people tend to associate more with others of their own “type”. What was that result of an ancient sociological study? Oh yes: “Birds of a feather flock together”. The data has been lost but the conclusion has survived.

Some of the dots on the graph are family, who may be viewed as unchosen associates. Or are they? Do we know if the researchers counted that grumpy cousin I don’t like and never see (though she lives only five miles away)? And other studies have shown that there are genetic factors influencing traits such as agreeableness and extroversion which may be associated with degree of happiness. So, if happy people tend to have happy sibs and cousins, this could be caused more by shared genetically-influenced traits than by their “contagious” influence on one another.

And, in a long-term study of human behavior like this one (twenty years), some less happy people who are around happier people may indeed benefit from the activities, the “vibes”, may even learn better behavior or learn how to fake it…but those who don’t will tend to drop away from the setting where they feel out of place. Or won’t be invited so often because they “just don’t seem to enjoy our dinners or outings”. So over time people settle out into groups they feel comfortable with. This can’t be really big news. Animal-study researchers don’t count many fervid PETA members among their circles of friends and close acquaintances, and vice versa. There’s a cause and effect here all right but it may not be the one being alleged in this study.

I should admit the obvious, that I don’t understand regression analysis and the other statistical tools that are used to verify the significance of associations in studies like this one. However, I don’t think it matters. We’re not talking about whether the associations exist, but about what they mean.

This is, of course, the weakness with observational studies as opposed to experimental ones. All the observer can say is what was observed; cause and effect relationships are speculative in all but the simplest of situations (dropping things off a tower, for example: Yes! they fall because they were dropped!). In this case, an experimental study might try to find a way to cause happy and unhappy people to hang around together for months or years and see what the results are. But how can this be done without denying people freedom of association, which is a factor in happiness? We could pay them to gather together, but what about those for whom no money is enough to make tolerable the company of such damnably cheerful/such oppressively dismal folks? Individuals have even been known to change jobs because they couldn’t stand the people they worked with.

Figuring out complicated things just can’t be as easy as the media, and perhaps some scientists, would wish. And in this discussion, we haven’t even gotten to evaluating the definition of “happiness”!