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Echo Chambers on Facebook

15 Pages Posted: 15 Jun 2016  

Walter Quattrociocchi

IMT Lucca

Antonio Scala

CNR - Intitute for Complex Systems

Cass R. Sunstein

Harvard Law School; Harvard University - Harvard Kennedy School (HKS)

Date Written: June 13, 2016


Do echo chambers actually exist on social media? By focusing on how both Italian and US Facebook users relate to two distinct narratives (involving conspiracy theories and science), we offer quantitative evidence that they do. The explanation involves users’ tendency to promote their favored narratives and hence to form polarized groups. Confirmation bias helps to account for users’ decisions about whether to spread content, thus creating informational cascades within identifiable communities. At the same time, aggregation of favored information within those communities reinforces selective exposure and group polarization. We provide empirical evidence that because they focus on their preferred narratives, users tend to assimilate only confirming claims and to ignore apparent refutations.

Keywords: Facebook, conspiracy theories, cascades, polarization, echo chambers

Suggested Citation

Quattrociocchi, Walter and Scala, Antonio and Sunstein, Cass R., Echo Chambers on Facebook (June 13, 2016). Available at SSRN:

Walter Quattrociocchi (Contact Author)

IMT Lucca ( email )

3392922276 (Phone)

Antonio Scala

CNR - Intitute for Complex Systems ( email )

Via dei Taurini 19
Rome, 00185

HOME PAGE: http://

Cass Sunstein

Harvard Law School ( email )

1575 Massachusetts Ave
Areeda Hall 225
Cambridge, MA 02138
United States
617-496-2291 (Phone)

Harvard University - Harvard Kennedy School (HKS) ( email )

79 John F. Kennedy Street
Cambridge, MA 02138
United States

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