Polarization and echo chambers in Reddit's political discourse

TL;DR

This study challenges the belief that Reddit is resistant to polarization by revealing clear ideological communities and echo chambers during the 2016 US election, using statistical validation of user and content data.

Contribution

The paper introduces a network validation approach to identify ideological communities and demonstrates polarization and echo chambers on Reddit during a major election.

Findings

Reddit exhibits distinct Democratic, Conservative, and Banned communities.

Election periods increase cross-group engagement and align content.

Linguistic diversity within groups decreases during elections.

Abstract

Political debate nowadays takes place mainly on online social media, with election periods amplifying ideological engagement. Reddit is generally considered more resistant to polarization and echo chamber effects than platforms like Twitter or Facebook. Here, we challenge this assumption through a case study across the 2016 US presidential election. We use statistical validation techniques to extract ideologically distinct communities of subreddits, in terms of their contributing user base and news consumption, which we use to analyze the dynamics of political debate. We thus reveal clear polarization in both interaction-based and topic-based communities, with clusters of Democratic, Conservative, and Banned subreddits. Election periods intensify cross-group engagement, align Banned and Conservative content, and reduce linguistic diversity within groups. Overall we characterize Reddit as a polarized environment marked by the presence of echo chambers, highlighting network validation as a key method for identifying behavioral and interaction patterns on online social media.