The paradox is resolved by the important point, outlined by one of the study’s authors, John Cacioppo, that ‚ÄúLoneliness isn‚Äôt being alone, it‚Äôs feeling alone”. In other words, it’s not about having social contact but about feeling like you have meaningful relationships.
This feeling, it turns out, was increased or was more likely to occur when one person had contact with a person who already reported themselves to be feeling lonely.
The paper Cacioppo co-wrote with Christakis and Fowler, published in the current issue of the Journal of Personality and Social Psychology, found that having a friend who reports feeling lonely makes a person 52 percent more likely to feel lonely. In another measure, they found that, for each additional day per week a person reported feeling lonely, his friends reported an additional lonely day per month. Not only that, having a friend who has a friend who feels lonely makes a person 25 percent more likely to feel lonely, and at three degrees of separation (a friend of a friend of a friend) the odds are still increased by 15 percent…
The spread of loneliness seems to have its own particular characteristics. Women, for example, seem to be more susceptible than men. Also, the more lonely people a person knows, the more likely she herself is to become lonely. That trait distinguishes loneliness from something like alcoholism: Having an alcoholic friend increases your odds of becoming an alcoholic, but having three alcoholic friends makes you no more likely than having just one…
Distance also seems to matter to the spread of loneliness. The authors found that living close to a lonely friend was more likely to make their loneliness contagious – if the friends lived more than a mile apart there was no significant effect. This was in contrast to obesity, which, Christakis and Fowler have found, doesn‚Äôt require physical proximity to spread. In other work, the two have found that an obese friend who lives in the next state can still make you more likely to gain weight.
Not mentioned by the Globe article was the interesting finding that loneliness spreads most strongly through mutual friends but only weakly through family members.
The study, which you can read the study in full as a pdf, was drawn from data from the famous Framington Heart Study which tracked the health of a small community over many years and, rather fortuitously, asked who was related to and friends with who, initially for the purposes of tracking people down if the researchers lost contact.