Really interesting article on the impact that peers have on adult behavior. Smokers lead others to smokers. Fat people can cause others to be fat. The methodology sounds a bit problematic. Critics says that the researchers were unable to prove causality and had instead just shown homophily.
Still, their findings sound correct. One of the researchers had become involved in the study because he was interested in whether there was a peer group effect on voting behavior. The article never followed up on this point.
I'm curious whether social networking software can lead to a peer group effect on political participation. If all your friends are posting status updates about voting for Candidate X, are you more likely to vote for Candidate X? Several friends posted status updates about voting in the NY primaries yesterday. Did this make their friends more likely to vote?