However, when scientists investigated social media echo chambers, they found surprisingly little evidence of them on a large scale – or at least none on a scale large enough to warrant the growing concerns. And yet, selective exposure to news does increase polarization. This suggested that these studies missed part of the picture of Americans’ news consumption patterns. Crucially, they did not factor in a major component of the average American’s experience of news: television.
We first measured just how politically siloed American news consumers really are across TV and the web. Averaging over the four years of our observations, we found that roughly 17% of Americans are politically polarized – 8.7% to the left and 8.4% to the right – based on their TV news consumption. That’s three to four times higher than the average percentage of Americans polarized by online news.
Moreover, the percentage of Americans polarized via TV ranged as high as 23% at its peak in November 2016, the month in which Donald Trump was elected president. A second spike occurred in the months leading into December 2018, following the “blue wave” midterm elections in which a record number of Democratic campaign ads were aired on TV. The timing of these two spikes suggests a clear connection between content choices and events in the political arena.
Staying in TV echo chambers
Besides being more politically siloed on average, our research found that TV news consumers are much more likely than web consumers to maintain the same partisan news diets over time: after six months, left-leaning TV audiences are 10 times more likely to remain segregated than left-leaning online audiences, and right-leaning audiences are 4.5 times more likely than their online counterparts.
While these figures may seem intimidating, it is important to keep in mind that even among TV viewers, about 70% of right-leaning viewers and about 80% of left-leaning viewers do switch their news diets within six months. To the extent that long-lasting echo chambers do exist, then, they include only about 4% of the population.