Not only do your happy feelings spread through your social network, your happiness can be increased by people you’ve never even met, reports a study from Harvard Medical School.
Harvard Medical School professor of sociology Nicholas Christakis and University of California at San Diego associate professor of political science James Fowler studied data from the Framingham Heart Study, a cardiovascular research project started in 1948. These researchers analyzed administrative tracking sheets from 1971, social and family ties, and participants’ answers on a depression index that measures happiness.
They discovered that when an individual becomes happier, a friend living within a mile experiences a 25 percent increased chance of happiness. A spouse is 8 percent more likely to be happy, siblings living within one mile are 14 percent more likely, and next-door neighbors are 34 percent more likely.
Christakis and Fowler were particularly surprised that indirect relationships — friends of friends of friends, whom the particular individual has never met — influence happiness levels. “We’ve found that your emotional state may depend on the emotional experiences of people you don’t even know, who are two to three degrees removed from you,” says Christakis.
They also found that happy feelings are limited by time and geography. That is, the effects of someone else’s happiness on your mood lasts less than a year. And the physically closer your happy friends are, the more likely you’ll enjoy increased happiness levels.
So, if you’re happy and you know it, thank your friends! But if you’re unhappy, don’t blame them — these researchers found that sad feelings don’t spread through social networks in the same way.