Smoking Is Addictive, but Quitting Is Contagious

People quit smoking as groups and not as individuals, a new study found.

Over the last 30 years, the number of smokers has steadily decreased — a tribute to the efforts of public-health workers everywhere. And while this fact is unarguable, less obvious are the social and cultural forces that lead an individual to kick the habit.

In fact, when someone crumbles that last empty pack of their favorite unfiltered brand and vows to never buy another, he might not realize that he is less like the heroic individual grasping his own boot straps and more like a single bird whose sudden left turn is just one speck in the larger flock.

These are the findings of a massive longitudinal study spanning 32 years: people quit smoking in droves. Through reconstructing the social network of 12,067 individuals, researchers from Harvard Medical School and the University of California, San Diego have discovered that smoking cessation occurs in network clusters and is hardly the isolated decision it might feel like to the individual quitter.

“We’ve found that when you analyze large social networks, entire pockets of people who might not know each other all quit smoking at once,” says Nicholas Christakis, a professor in Harvard Medical School’s Department of Health Care Policy, who, along with U.C. San Diego researcher James Fowler, authored the study.

The study, which was funded primarily by the National Institute on Aging, appears in the May 22 issue of the New England Journal of Medicine.

Christakis illustrates this point by describing a small network containing three individual smokers, persons A, B, and C. The first person, A, is friends with B, and B is friends with C, but A and C do not know each other. If C quits smoking, A’s chances of not smoking spike 30 percent, regardless of whether or not B smokes. The middle individual, it would appear, might act as a kind of “carrier” for a social norm.

Education also seems to matter. We are more influenced by the quitting behavior of others if those people are highly educated. To add a further twist, we are also more influenced by others if we ourselves are more educated.

Says Christakis, “We see by this that the educated are not only more influential, but they are also more easily influenced.”