People work all winter to avoid catching a cold or flu from those around them, but a new study reveals that something much sunnier spreads through daily contact: Happiness.
Friends, spouses, siblings and neighbours influence each other's happiness when they become happy themselves, researchers have found -- but only if they live nearby and cross paths regularly. What's more, these effects extend to three degrees of separation in real-life social networks.
"Your happiness depends on the happiness of dozens of other people that you don't know and have never met," says James Fowler, a political-science professor at the University of California, San Diego. "But the flip side of that is that your own happiness is going to ripple out and affect dozens of other people, so when you become happy it makes other people happier. When you smile, the world smiles with you."
In fact, the researchers determined that given a choice between a $5,000 raise or a friend's friend becoming happy, the latter is more likely to boost your mood.
"Our work shows that happiness is not merely about an individual pursuit -- it's about the collective journey we are taking with friends and family and how our connections bind us together," Fowler says.
The findings have important public health implications because they suggest a need to insulate social networks from the ripple effects of sick or depressed individuals, he says, or the potential to help people care for themselves by encouraging connections with happy peers.
The researchers mined the Framingham Heart Study, an extraordinary database that has tracked entire networks of family and friends from Framingham, Mass., over three generations. The happiness study, to be published in the British Medical Journal today, focused on 4,793 people with more than 53,000 different social ties.
Fowler and his co-author, Nicholas Christakis of Harvard Medical School, have also tracked socially contagious patterns of obesity, smoking, loneliness and depression.
"We were ready to talk about something positive rather than something negative," Fowler says.
They were surprised to find that physical proximity was important to the spread of happiness because obesity showed the opposite pattern, with long-distance loved ones affecting weight-gain as much as those who live next door. Fowler speculates that emotional influence relies more on frequent contact, citing their finding that people's next-door neighbours affect their happiness, but those two houses down -- with whom they likely share a similar socioeconomic status but not a personal relationship -- don't.
"We found here a very, very strong impact of distance," he says. "A lot of these results, they're about your friends, family and neighbours who live very close to you, people you see everyday probably."
PUZZLED RESEARCHERS
Co-workers, however, seem to have no effect. That initially puzzled the researchers, until they considered the nature of those relationships.
Close friends at work probably do affect our happiness, Fowler says, but people would most likely identify those people as friends rather than co-workers on the study questionnaire. Co-workers with no personal relationship, however, create a "zero-sum" situation in which one person's happiness may come at the expense of the other's disappointment, he says.
"Your non-friends at work may actually be competing with you for promotions, for praise from the boss or for commissions," he says.
"Because there's a competitive environment, their happiness may actually be the result of them getting something that you didn't get."
The study also revealed that these influences on happiness are temporary and people eventually return to their own innate emotional state -- however sunny or brooding it might be.
Friends, spouses, siblings and neighbours influence each other's happiness when they become happy themselves, researchers have found -- but only if they live nearby and cross paths regularly. What's more, these effects extend to three degrees of separation in real-life social networks.
"Your happiness depends on the happiness of dozens of other people that you don't know and have never met," says James Fowler, a political-science professor at the University of California, San Diego. "But the flip side of that is that your own happiness is going to ripple out and affect dozens of other people, so when you become happy it makes other people happier. When you smile, the world smiles with you."
In fact, the researchers determined that given a choice between a $5,000 raise or a friend's friend becoming happy, the latter is more likely to boost your mood.
"Our work shows that happiness is not merely about an individual pursuit -- it's about the collective journey we are taking with friends and family and how our connections bind us together," Fowler says.
The findings have important public health implications because they suggest a need to insulate social networks from the ripple effects of sick or depressed individuals, he says, or the potential to help people care for themselves by encouraging connections with happy peers.
The researchers mined the Framingham Heart Study, an extraordinary database that has tracked entire networks of family and friends from Framingham, Mass., over three generations. The happiness study, to be published in the British Medical Journal today, focused on 4,793 people with more than 53,000 different social ties.
Fowler and his co-author, Nicholas Christakis of Harvard Medical School, have also tracked socially contagious patterns of obesity, smoking, loneliness and depression.
"We were ready to talk about something positive rather than something negative," Fowler says.
They were surprised to find that physical proximity was important to the spread of happiness because obesity showed the opposite pattern, with long-distance loved ones affecting weight-gain as much as those who live next door. Fowler speculates that emotional influence relies more on frequent contact, citing their finding that people's next-door neighbours affect their happiness, but those two houses down -- with whom they likely share a similar socioeconomic status but not a personal relationship -- don't.
"We found here a very, very strong impact of distance," he says. "A lot of these results, they're about your friends, family and neighbours who live very close to you, people you see everyday probably."
PUZZLED RESEARCHERS
Co-workers, however, seem to have no effect. That initially puzzled the researchers, until they considered the nature of those relationships.
Close friends at work probably do affect our happiness, Fowler says, but people would most likely identify those people as friends rather than co-workers on the study questionnaire. Co-workers with no personal relationship, however, create a "zero-sum" situation in which one person's happiness may come at the expense of the other's disappointment, he says.
"Your non-friends at work may actually be competing with you for promotions, for praise from the boss or for commissions," he says.
"Because there's a competitive environment, their happiness may actually be the result of them getting something that you didn't get."
The study also revealed that these influences on happiness are temporary and people eventually return to their own innate emotional state -- however sunny or brooding it might be.
