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Why Do Partisan Media Polarize Viewers?


  • The author thanks Daniella Lejitneker and the staff of the Wharton Behavioral Lab for helping to implement experiment 1 in the article. I would like to thank Kevin Arceneaux, Paul Beck, Adam Berinsky, Robin Blom, John Bullock, Jamie Druckman, Bob Erikson, Stanley Feldman, John Gasper, Don Green, Greg Huber, Luke Keele, Jonathan Ladd, Gabriel Lenz, Neil Malhotra, Marc Meredith, Diana Mutz, Jeremy Pope, Rogers Smith, Laura Stoker, Josh Tucker, the editor, anonymous referees, and many others for helpful comments. Seminar participants at APSA 2011, Berkeley, MIT, Northwestern, NYU-CEES, and Stanford also gave very useful feedback. Any remaining errors are my own.


The recent increase in partisan media has generated interest in whether such outlets polarize viewers. I draw on theories of motivated reasoning to explain why partisan media polarize viewers, why these programs affect some viewers much more strongly than others, and how long these effects endure. Using a series of original experiments, I find strong support for my theoretical expectations, including the argument that these effects can still be detected several days postexposure. My results demonstrate that partisan media polarize the electorate by taking relatively extreme citizens and making them even more extreme. Though only a narrow segment of the public watches partisan media programs, partisan media's effects extend much more broadly throughout the political arena.