Economist Robert Frank studies peer pressure and how its power can be leveraged for good. In his new book, "Under the Influence: Putting Peer Pressure to Work," Frank explains the idea of "behavioral contagion," which he says can drive people to do what's right. Paul Solman talks to Frank about applications for fighting climate change and real-life examples in Frank's hometown of Ithaca, New York. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders