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.

For all the attention that Fox News and MSNBC receive, their audiences are still considerably smaller than the number of people watching broadcast news. For example, during a week in which Fox’s Bill O’Reilly drew an average of 3.4 million viewers, CBS Evening News alone pulled 10.2 million. And both those numbers pale in comparison to the 130 million people in the US who show up for national elections. How much influence could cable news have on people who don’t watch it?

Arceneaux and Martin set up a series of experiments, with nearly 1,700 participants in total, built on a central premise: what if the participants could choose to watch something else? In addition to episodes of Fox News and MSNBC programs, two entertainment options from the same time slot and with similar ratings (think Dirty Jobs) were used. Some participants were randomly assigned to watch one of the four options, while others were given the ability to “channel surf” for the duration of their time. Those who were given that freedom were pretty neatly divided—some mostly watched the partisan news programs, while others mainly sought some entertainment. Fewer people were indecisive.

The researchers looked for the ability of partisan news to influence people’s opinions on things like health care, the economy, terrorism, and approval of President Obama’s performance. They also investigated the media’s ability to determine which political issues are viewed as most important.

Virtually across the board, the group with the freedom to choose what they watched was less influenced than those who were forced to watch Fox News or MSNBC. One reason for that is obvious—many of them didn’t watch the news programs. Another reason became clear when participants were simply asked beforehand which program they’d prefer to be assigned to watch.

By separating people into “news seekers” (those who said they’d prefer to watch the news programs) and “entertainment seekers," an interesting pattern is revealed. Entertainment seekers who were assigned to watch one of the partisan programs (much to their disappointment) were actually much more influenced by them than news seekers watching the same shows. News seekers are presumably more aware of current political debates and may have already formed their own opinions, making new information less likely to change their thinking.

The book makes a pretty good case that, together, these factors have caused other studies to exaggerate the societal impact of the cable news shoutosphere. If you bring in a random group and force them to watch partisan news, you’re including a lot of people who would never watch that stuff on their own. If you remove those people (by letting them watch Mike Rowe complain about how bad that thing smells instead), the apparent persuasive effectiveness drops quite a bit.

That makes things seem a lot less like a case of cable news polarizing the American public and a lot more like cable news delivering a product that appeals to the poles of the American public. That’s not to say partisan news has no effect. Arceneaux and Martin just believe that the effect appears to be much smaller than others have hypothesized. People aren’t sponges that unquestioningly absorb everything they hear. They have their own ideas and the ability to choose what they listen to.

“From our perspective,” they write, “the reason to be ill at ease with the state of partisan news is not because it polarizes or even because it misleads. Rather, the reason to be concerned with these shows revolves around the content itself.” That is, the shows have tremendous opportunities to help the public become more informed, but their effort is largely expended on decidedly different pursuits.

The book covers more ground than just this central point, investigating whether watching partisan news from the opposite side of the political spectrum tends to soften or bolster one’s opinions and how partisan news influences perceptions of media bias. It also provides historical context for our current predicament by reviewing research and societal concerns about news media from decades past.

It’s a very accessible read that still manages to provide the data for your own consideration. If you’re interested in how modern media influence political debate (including debate on scientific issues), you’ll find lots of fodder for pondering. And if arguments about cable news are a significant source of stress for you, you might find the book’s balm soothing. It’s OK—you can look away from the infuriating whack-a-moles sometimes. Most people already do.