When is keeping up with the Joneses a good thing? Well, when someone installs rooftop solar panels, their neighbors are increasingly likely to do the same. It’s part of a phenomenon called behavioral contagion, which can either have positive effects, as with solar panels, or negative effects, as when people become more likely to drink excessively when they spend time with heavy drinkers. In "Under the Influence," economist Robert H. Frank talks about how peer influences alter the policy choices we face under COVID-19 and climate change, and how we can better harness the power of contagion for good. Taught by Robert H. Frank, the Henrietta Johnson Louis Professor of Management and Professor of Economics at Cornell's Johnson Graduate School of Management.