Why are online echo chambers, that is, spaces in which social media users are surrounded by like-minded others, a threat to democratic systems? One response to this question often is: Groups in which individuals mutually reinforce their opinions are most likely to become more extreme in their views, resulting in a process of political polarization. This is thought to harm democracy since political polarization may go hand in hand with social fragmentation (Sunstein, 2017), in which ideological dissimilar groups become more distant to each other, avoiding discussions with each other and fortifying the mindset of “us against them.”

But does social media use generally lead to political polarization?

First, let’s see what current studies have found out:

By asking 1,032 adult Americans about their use of social networking sites, Lee, Choi, Kim, and Kim (2014) found that the more time users spent on social networking platforms, the more ideologically diverse was their online environment (consisting of both, republicans and democrats; see also Myth 1). This online diversity, in turn, was associated with a reduced partisan, ideological, and topical polarization. This association, however, applied only for those who also engaged in discussions with their diverse environment. While these findings indicate that the use of social media – through its heterogeneity – might be connected to less polarization, this study relies on a survey at one specific point of time. Therefore, we cannot conclude whether those less polarized are exposed more to social media or whether certain social media use patterns reduce individual polarization. To address these relationships, Beam, Hutchens, and Hmielowski (2018) asked 500 U.S. adults about their social media use at three different points of time (in the period August – October 2016) during the 2016 U.S. presidential election campaign. This long-term survey revealed that those who were more polarized (i.e., perceive greater emotional distance to the opposing party) used Facebook for news consumption less often. Increased news consumption on Facebook, however, reduced individual polarization over time (especially for those who encountered news challenging their point of view). Considering that Facebook news use was generally rather infrequent, the authors come to the conclusion: “our study indicates that news on Facebook, social media filter bubbles, and echo chambers may not be the culprit for rising citizen polarization” (Beam et al., 2018, p. 952).

Still, reality might be more complex when focusing on those who are already politically extreme and members of online echo chambers.

Does engagement in politically extreme echo chambers increase polarization?

By analyzing large scale public discussions on Twitter in 23 countries, Bright (2016) found that especially those sitting “at the extreme ends of the ideological scale” (p. 1) are members of homogeneous echo chambers, fortifying political fragmentation. This pattern is in line with a multi-method study with Israel web users: Dvir-Gvirsman (2017) found that people with more extreme political ideologies were more likely to seek out homophily in their online environment. This homogenous online surrounding, in turn, increased the ideological extremity over time.

To draw preliminary conclusions: When focusing on the group of social media users as a whole, online communication with its weak echo chambers does not appear to induce or strengthen political polarization. But when politically extreme users engage in strong echo chambers, using social media technologies can contribute to an increased polarization. Given current developments in online communication the question arises of how manipulative interventions such as the spread of disinformation (“fake news”) or the emergence of artificial entities (i.e., “social bots”) might affect the process of political polarization in weak and strong echo chambers.


Beam, M.A., Hutchens, M. J., & Hmielowski, J. D. (2018). Facebook news and (de)polarization: reinforcing spirals in the 2016 US election. Information, Communication & Society, 21, 940–958, doi:10.1080/1369118X.2018.1444783

Bright, J. (2017). Explaining the emergence of echo chambers on social media: The role of ideology and extremism Available at SSRN: dx.doi.org/10.2139/ssrn.2839728

Dvir-Gvirsman, S. (2017). Media audience homophily: Partisan websites, audience identity and polarization processes. New Media & Society, 19, 1072–1091. doi:10.1177/1461444815625945

Lee, J. K., Choi, J., Kim, C., & Kim, Y. (2014). Social media, network heterogeneity, and opinion polarization. Journal of Communication, 64, 702–722. doi:10.1111/jcom.12077

Sunstein, C. R. (2017). #Republic: Divided democracy in the age of social media. Princeton, NJ: Princeton University Press.

Myth 3: Online echo chambers are responsible for contemporary political extremism
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