Dehghan, E., Carlon, D., Kasianenko, K., Nagappa, A., & Suresh, V. P. (2026). The entangled dynamics leading to the sedimentation of polarisation on political Reddit. Information, Communication & Society, 1–24. https://doi.org/10.1080/1369118x.2026.2623523
Summary
This paper examines cross-ideological communication across 11 major political subreddits over 16 years, measuring overlaps in users, information sources, cross-posting, cross-commenting, subreddit links, and discursive identities. Across every indicator, the authors find minimal overlap—even between subreddits that are discursively similar—directly challenging the common framing of r/politics as a cross-ideological “town square” or Habermasian public sphere. Rather than treating polarization as an emergent outcome of any single force, they advance the concept of the sedimentation of polarisation: political subreddits operate as if already in opposition to all others, a condition arising from the entanglement of platform design, moderation practices, user agency, discourses, and socio-political context. Grounded in Laclau and Mouffe’s discourse theory and assemblage thinking, the paper argues for a “discursive-digital entanglement” approach that refuses to privilege either platform materiality or user discourse.
Key Contributions
- Introduces “sedimentation of polarisation” as a discursive-digital precondition of polarized communication, not merely its outcome.
- Develops the Normalised Similarity Score (NSS), a method for comparing cross-community overlaps while controlling for subreddit size and activity differences.
- Provides large-scale empirical evidence that r/politics does not function as a cross-ideological bridging space.
- Extends polarization research beyond the left-right binary, documenting fragmentation among ideologically aligned communities.
- Offers a non-hierarchical framework treating platform design, moderation, user agency, and discourse as entangled co-constituents.
- Addresses the comparatively thin empirical literature on Reddit as a site of political communication.
Methods
A mixed-methods analysis of 16 years of submissions and comments from 11 political subreddits (e.g., r/politics, r/Conservative, r/Libertarian, r/progressive, r/democrats, r/Republican, r/esist, r/DemocraticSocialism). The authors construct an NSS comparing observed overlaps to expectations based on geometric means of contribution rates and contributor counts, applied across shared domains, shared URLs, linked subreddits, cross-submitting users, and cross-commenting users. They complement this with corpus-assisted discourse analysis via keyness (log-likelihood) in AntConc—using r/politics as the reference corpus—and a two-coder thematic analysis of subreddit descriptions, rules widgets, and wikis to characterize moderation features.
Findings
- No subreddit pair reached NSS ≥ 1.0 on shared domains; the highest (r/progressive–r/DemocraticSocialism, 0.879) still fell short.
- URL-level overlaps were dramatically lower than domain-level ones (the same pair dropped from 0.879 to 0.094), meaning even shared sources yield different specific stories.
- Cross-posting never exceeded NSS = 0.206 and cross-commenting never exceeded 0.280; users rarely leave their “homebase.”
- r/politics shows uniformly low overlap with both left- and right-leaning subreddits, contradicting claims of clear left bias and undercutting its “town square” framing.
- Right-leaning subreddits cluster around shared antagonists (“woke,” “cancel culture,” “the left”); left-leaning ones are more topically diverse.
- Moderation rules visibly shape language: strict-civility spaces show little derogatory language, while minimally moderated ones use loaded slurs.
- Intra-ideological splits (e.g., r/conservatives as a “minimally moderated” alternative to r/Conservative) show polarization emerging from moderation conflicts, not just ideology.
Connections
This work sits within the computational study of network fragmentation and echo chambers, offering a Reddit-based counterpoint to the influential Facebook-based findings on ideological exposure in Bakshy2015-rn and to affective/interaction-graph approaches such as Minici2024-tf. Its critique of the “public sphere” framing and attention to how platform architecture and moderation constitute discourse resonate with deliberation- and moderation-focused work like Esau2025-tf, while its insistence that polarization is not reducible to a left-right binary connects to broader rethinkings of partisan structure in Tornberg2025-ir.
Podcast
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