clipped from www.washingtonpost.com

When researchers analyzed the patterns of those who managed to quit smoking over the 32-year period, they found that the decision appeared to be highly influenced by whether someone close to them stopped.

a growing body of evidence is suggesting that traditional social networks play a surprisingly powerful and underrecognized role in influencing how people behave

Christakis and Fowler took advantage of detailed records kept between 1971 and 2003 about 5,124 people who participated in the landmark Framingham Heart Study. Because many of the subjects had ties to the Boston suburb of Framingham, Mass., many of the participants were connected somehow -- through spouses, neighbors, friends, co-workers -- enabling the researchers to study a network that totaled 12,067 people

In a study published last week in the New England Journal of Medicine, the team found that a person's decision to kick the habit is strongly affected by whether other people in their social network quit