Are partisan news sources polarizing Americans?

People love to get mad about news coverage in the media—or, at least, it’s hard not to. Thinking about your least favorite cable news channel or newspaper might make you feel as if you’ve been playing a whack-a-mole game where all the moles evade your mallet perfectly while hurling shockingly effective personal insults. Those writers and TV personalities probably aren’t the only people you think of as liars or jerks, but the fact that they can broadcast (literally or metaphorically) their opinions to such large audiences might make you bristle.

There are real demographic and ideological differences between the audiences of Fox News, MSNBC, and the evening broadcast news. Viewers of partisan cable news networks are considerably more polarized. It’s obvious that more conservatives than liberals watch Fox News, but does watching Fox News make people more conservative? This is the oft-voiced concern about the modern news environment—that echo chambers drive people further apart.

Some studies have tried to examine that possibility and have found that watching some partisan programming can be persuasive, altering the opinions people express afterward. However, professors Kevin Arceneaux of Temple University and Martin Johnson of the University of California-Riverside suspected these studies failed to properly characterize the real-world impact of partisan news. In their book Changing Minds or Changing Channels? (a copy of which was provided to Ars by the publisher), they describe the studies they undertook to investigate the impact of the humble remote control on the power of the partisan media.