In August 2016, in the middle of the U.S. presidential campaign, there was a rumor that the candidate Hillary Clinton was so poor in health that she would not be fit for the presidency. The news spread very quickly through social networking platforms and was soon picked up by conservative media and eventually instrumentalized by the opposing candidate as part of his election campaign. As it soon turned out, the rumors surrounding Clinton’s health were cast by conspiracy theorists, and although the public received a medical certificate attesting to Clinton’s health, more and more “evidence” surfaced on social media, thus, keeping the topic alive for a long time. This case is seen as a prototypical example of how so-called fake news (i.e., news that are intended to spread misinformation) are deliberately disseminated to influence public opinion and political events, amplified by social media (Marwick & Lewis, 2017).

Ever since the last U.S. presidential election, the role of social media in the spread and impact of fake news has been emphasized in the public scene. Accordingly, misinformation is thought to have a particularly strong effect when it is distributed within segregated, homogeneous networks (i.e., echo chambers, see Fake news: How our brains lead us into echo chambers that promote racism and sexism). By constant exposure to misinformation and by experiencing its broad appeal within one’s own social network, fake news might quickly become a subjective reality that would then resist any refutation. But can this be shown empirically? What do studies tell us that investigate the effects of fake news? First of all, the general question arises what the significance of echo chambers on social media really is. While strong echo chambers cannot be found for the group of social media users as a whole (Myth 2), ideologically homogeneous online networks were identified among those who are inclined to adopt extreme political views. Those networks can contribute to individual polarization (Myth 3) which – theoretically – could be fostered by the spread of misinformation. But what are the factors that make individual users susceptible to believe in misinformation? A recent study dealt with this question focusing on misinformation in the form of conspiracy theories: Garrett and Weeks (2017) found that general subjective beliefs about how to recognize truth influence one’s belief in conspiracy theories. The findings imply that especially those believe in fake news who think that the truth is something politically constructed and those who think that they have an intuitive sense of truth. On the other hand, people for whom truth can and must be measured by hard, objective facts were less likely to believe in conspiracy theories.

Of course, these findings do not offer evidence on the impact of echo chambers on the acceptance of misinformation but it suggests for which users the exposure to falsehoods can have negative effects. But back to the example outlined above: Could it be that fake news spread on social media decisively influenced the 2016 U.S. election? And: how much did echo chambers contribute to that? These questions were addressed by a study that asked people for their news consumption during the U.S. election campaign (Allcott & Gentzkow, 2017). This study found that the respondents were exposed to misinformation rather seldomly in the period under review and respondents did not very much believe in the veracity of that kind of information. In particular, it emerged that the ideological homogeneity of a respondent’s social networks had no impact on the belief in a news article containing fake news. However, looking only at respondents who clearly aligned themselves with a political camp (Republicans or Democrats), the homogeneity of their own social networks had an impact on the perceived credibility of fake news. The more homogeneous the social networks of a democrat or republican respondent were, the more likely they were to believe fake news, especially if the content was against the other or in favor of their own party. Put together, these findings indicate that people may actually be more inclined to believe fake news when they are within ideological echo chambers. Yet, it remains unclear whether interacting in strongly homogeneous online networks automatically leads to accepting misinformation supporting one’s pre-existing views per se or whether believing in the truthfulness of falsehoods results from an interplay between environmental variables (e.g., strong echo chambers) and the individual susceptibility to, for instance, conspiracy beliefs.

Social media allow anyone to spread claims without them being subjected to systematic fact-checking. Echo chambers may, under certain circumstances, help make misinformation a subjective reality for some users. Not least in view of the potentially very far-reaching social and political consequences, research is called to address the interplay of fake news exposure and echo chambers in the future.



Allcott, H., & Gentzkow, M. (2017). Social Media and Fake News in the 2016 Election. Journal of Economic Perspectives, 31(2), 211–236.

Garrett, R. K., & Weeks, B. E. (2017). Epistemic beliefs’ role in promoting misperceptions and conspiracist ideation. PLOS ONE, 12(9), e0184733.

Marwick, A., & Lewis, B. (2017). Media Manipulation and Disinformation Online. New York: Data & Society Research Institute. Retrieved from

Myth 5: Through echo chambers, “fake news” have a stronger impact
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