The Feature

Is Happiness Catching?

[T]wo years ago, a pair of social scientists named Nicholas Christakis and James Fowler used the information collected over the years about Joseph and Eileen and several thousand of their neighbors to make an entirely different kind of discovery. By analyzing the Framingham data, Christakis and Fowler say, they have for the first time found some solid basis for a potentially powerful theory in epidemiology: that good behaviors — like quitting smoking or staying slender or being happy — pass from friend to friend almost as if they were contagious viruses.