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Conspiracy and Environment Communities on Reddit Sort Along Different Demographic Axes

Conspiracy and Environment Communities on Reddit Sort Along Different Demographic Axes

Authors: Miguel A. Sánchez-Cortés, Corrado Monti, Gianmarco De Francisci Morales

Venue: arXiv cs.SI, 2026 — arXiv:2609.34846

TL;DR

Conspiracy and environmental communities on Reddit exhibit distinct demographic sorting mechanisms. Conspiracy communities show upstream sorting—users self-segregate by gender and partisanship before entry through ideologically-aligned information environments. Environmental communities show downstream sorting—diverse users converge on the issue but diverge in downstream engagement by age and affluence. These findings reveal that demographic polarization operates differently across identity-expressive versus issue-oriented online communities.

Contributions

  • Novel Stratified Attention Flow Graph (S-AFG) framework extending prior work to track how demographic groups traverse Reddit's ecosystem before entering target communities
  • Empirical evidence that demographic sorting operates at different stages (upstream vs. downstream) depending on community type
  • Identification of gateway and bridge subreddits that funnel specific demographic groups toward conspiracy and environmental communities
  • URL analysis showing that user groups consume demographically distinct information sources before joining communities
  • Methodological contribution: sociodemographic profiling of users inferred from posting behavior across subreddit embeddings

Method

The paper constructs a novel dataset of Reddit activity from 2019–2023 (50M posts from 4.5M users, 10% random sample to manage computational cost). Social dimensions (age, gender, affluence, partisanship) are inferred for each user by leveraging subreddit embeddings, projecting users onto latent social axes using the methodology from Waller & Anderson (2021).

The core methodological contribution is the Stratified Attention Flow Graph (S-AFG), extending the Attention Flow Graph framework. The S-AFG tracks how attention flows between subreddits while conditioning on user demographics. For each social dimension, the authors compute dimension-specific flow networks weighted by users' sociodemographic scores, enabling identification of how different groups navigate the Reddit ecosystem before reaching target communities.

The authors apply community detection (Infomap) on the filtered AFG to identify politically salient communities, then focus on two contrasting cases: Conspiracy and Environment. They measure demographic differentiation via cross-community transition probabilities (using random walks on the S-AFG), identify gateway communities (high entry probability from outside), and characterize bridge communities (communities users traverse before reaching the target).

Results

Conspiracy communities show upstream demographic sorting: - Entry is primarily structured by gender and partisanship before users join the conspiracy subreddit - Masculine users arrive via ideologically explicit political subreddits (r/ConservativeCirclejerk, r/Paranormal) and right-wing media domains (Breitbart, Daily Wire) - Feminine users arrive via esoteric/spiritual subreddits (r/Wicca, r/AstralProjection, r/awakened) and generalist content (YouTube, Wikipedia) - Top bridges show r/CoronavirusCirclejerk, r/SocialistRA for masculine users; r/Retconned, r/tarot for feminine users

Environment communities show downstream demographic sorting: - Entry is less differentiated; diverse users converge on r/environment at similar rates - Sorting emerges downstream within the community by age and affluence - Affluent users engage with sustainability, technology, and economics-focused subreddits; less affluent users with protest and collective action - Gateway subreddits are differentiated by affluence (not partisanship): r/climate, r/renewable energy (affluent); r/ClimateOffensive, r/ExtinctionRebellion (less affluent)

URL analysis confirms these pathways: masculine conspiracy users share domains from the far-right media ecosystem before joining; feminine users share New Age and spirituality content; environmental users consume established news sources (CNN, Reuters, Twitter), with affluent users showing more interest in technology/finance angles.

Connections

Notes

Strengths: The S-AFG framework is a genuine methodological advance, enabling pathway analysis impossible with static network snapshots. The contrast between conspiracy and environmental communities is theoretically motivated (identity-expressive vs. issue-oriented) and empirically clear. The paper validates demographics against self-reported ages, reducing noise in scoring. Longitudinal window captures entry before engagement, isolating real pre-entry behavior.

Limitations: Sociodemographic inference is behavioral proxy, not ground truth—reflects subreddit associations, not actual identity. Analysis is limited to Reddit (visible behavior only; private messages and cross-platform routes invisible). Causality is not established (do users traverse to conspiracy because of prior partisanship, or does exposure radicalizes?). Community definitions rely on seed subreddits chosen by researchers; different seeds might yield different topologies.

Future work: Test generalizability to other identity-expressive (religious, cultural) and issue-oriented (healthcare, housing) communities. Link pre-entry pathways to subsequent radicalization trajectories. Investigate whether platform interventions on bridges/gateways change demographic flow patterns.