Photo: The Guardian

There is a study making the rounds this week, one that declares a certain social-networking site is the secret key to longevity. “Facebook Could Be Extending Your Life,” says People. How nice. “Facebook users less likely to die,” says the Independent. That’s great. “Could Facebook actually be good for you?” wonders the Verge. Maybe so!

And yet buried within this study, which was published this week in Proceedings of the National Academy of Sciences, is a deeply sad detail: In their study of more than 12 million Facebook users, the researchers found that a lower mortality risk was associated with the number of friend requests accepted — as in, those who accepted more friend requests tended to live longer than those who accepted fewer requests. Friend requests extended, on the other hand, had no particular relationship at all to mortality. As the news release so plainly phrased it, “This finding … suggests that public health interventions urging people to go out and try to make more friends may have no effect on health.”

This finding made James Fowler, a social scientist at the University of California, San Diego, and one of the study’s co-authors, sad, too. “The whole reason that I’m in this game is because I want to figure out how to use social networks to make people healthier,” he told Science of Us. “And, unfortunately, what that result tells us is that this is going to be harder than we thought it was … It suggests that it’s not possible to make people healthier by getting them to go out and seek new friendships.”

This is an observational study, which means that “if you find a positive association, it doesn’t mean that one thing causes the other,” Fowler explained. (In other words, headlines suggesting that Facebook causes longevity are definitely overreaching.) If you find no association, on the other hand — well, that does tell you that one thing probably does not cause the other.

Fowler, though, describes himself as an optimist, and says that if this thing about online friendships is true for real-life ones, maybe that suggests people should prioritize deepening the friendships they already have over widening their social networks. “In the real world, health behaviors are only transmitted between very close friends,” he said, referring to research that has suggested that sticking with a weight-loss program is easier if your close friends are doing it, too. Even so, he has to admit it has not been the cheeriest year for research concerning friendship.