The echo chamber effect on social media

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 118; no. 9; pp. 1 - 8
• Main Authors: Cinelli, Matteo, De Francisci Morales, Gianmarco, Galeazzi, Alessandro, Quattrociocchi, Walter, Starnini, Michele
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 02.03.2021
• Subjects: Abortion, Legal - psychology; Bias; Communication; Gun Violence - psychology; Humans; Information Dissemination; Narration; Patient Protection and Affordable Care Act - statistics & numerical data; Physical Sciences; Politics; Social Change; Social Media - trends; Social Networking; Social Sciences; Vaccination - psychology; polarization; echo chambers; social media; information spreading
• ISSN: 0027-8424; 1091-6490; 1091-6490
• DOI: 10.1073/pnas.2023301118

Social media may limit the exposure to diverse perspectives and favor the formation of groups of like-minded users framing and reinforcing a shared narrative, that is, echo chambers. However, the interaction paradigms among users and feed algorithms greatly vary across social media platforms. This paper explores the key differences between the main social media platforms and how they are likely to influence information spreading and echo chambers’ formation. We perform a comparative analysis of more than 100 million pieces of content concerning several controversial topics (e.g., gun control, vaccination, abortion) from Gab, Facebook, Reddit, and Twitter. We quantify echo chambers over social media by two main ingredients: 1) homophily in the interaction networks and 2) bias in the information diffusion toward like-minded peers. Our results show that the aggregation of users in homophilic clusters dominate online interactions on Facebook and Twitter. We conclude the paper by directly comparing news consumption on Facebook and Reddit, finding higher segregation on Facebook.