It's not just social media: Cable news has a bigger effect on polarization

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The last two election cycles have seen an explosion of attention to "echo chambers", or communities where a narrow set of opinions makes people less likely to challenge their own opinions. Much of this concern has focused on the rise of social media, which has radically transformed the news ecosystem.

However, when scientists investigated social media echo chambers, they found surprisingly little evidence on a large scale, or at least none on a large enough scale to justify the growing concerns. And yet, selective exposure to news increases polarization. This suggests that these studies have missed part of the picture of Americans' news consumption patterns. Basically, they failed to take into account a major element of the average American's information experience: television.

To fill this gap, I and a group of researchers from Stanford University, the University of Pennsylvania, and Microsoft Research tracked the television news consumption habits of tens of thousands of American adults each month. from 2016 to 2019. We uncovered four aspects of news consumption that, taken together, paint a troubling picture of the television news ecosystem.

The advantage of online television

We first measured how politically segregated American news consumers are on TV and the web. Averaged over the four years of our observations, we found that about 17% of Americans are politically biased – 8.7% left-wing and 8.4% right-wing – based on their television news consumption. That's three to four times the average percentage of Americans polarized by online news.

Furthermore, the percentage of Americans polarized via television reached 23% at its peak in November 2016, the month in which Donald Trump was elected president. A second spike occurred in the months leading up to December 2018, following the “blue wave” midterm elections in which a record number of Democratic campaign ads aired on television. . The timing of these two peaks suggests a clear link between content choices and events in the political arena.

Stay in the echo chambers of television

In addition to being more politically siled on average, our research found that TV news consumers are significantly more likely than web consumers to maintain the same partisan news regimes over time: after six months, left-leaning viewers are 10 times more likely to stay apart than left-leaning online audiences, and right-leaning audiences are 4.5 times more likely than their online counterparts.

While these numbers may seem daunting, it's important to keep in mind that even among viewers, around 70% of right-wing viewers and around 80% of left-wing viewers switch news diets within six month. To the extent that durable echo chambers exist, they only affect about 4% of the population.

Narrow TV regimes

We found that partisan segregation among viewers goes even further than left and right sources. We've identified seven broad categories of TV news sources, and then used those archetypes to determine what a typical, unvaried TV news diet really looks like.

We found that, compared to online audiences, TV news consumers tend not to stray too far from their preferred news sources. For example, most Americans who primarily consume MSNBC rarely consume news from sources other than CNN. Similarly, most Americans who primarily consume Fox News Channel do not venture...