Does political polarization cause citizens to seek out partisan media sources, or do partisan media push them toward more polarized views? A study coauthored by MIT political science professors Adam Berinsky and Teppei Yamamoto and postdoc Chloe Wittenberg, PhD ’23, finds that the answer is complicated.

The researchers combined a large online survey about the news people like to read with web-browsing data tracking the news sites the participants actually visited, finding differences between the two.  

When looking at participants’ stated media preferences in the survey, the researchers found that people may be receptive to information from sources they disagree with politically. But the web-browsing data instead suggested that people are primarily influenced by news outlets they already agree with.

“Together, these results suggest that inferences about media polarization may depend heavily on how individuals’ media preferences are measured,” they write.

Meanwhile, a paper by MIT philosopher Kevin Dorst, PhD ’19, explores the logical processes that can drive polarization, arguing that people understandably scrutinize evidence that contradicts their existing point of view more aggressively than evidence that supports it. People who develop radically different views, he concludes, are not necessarily being misled or reacting emotionally but, in part, responding rationally to genuinely ambiguous information.