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Conspiracy and Environment Communities on Reddit Sort Along Different Demographic Axes

Miguel Á. Sánchez-Cortés, Corrado Monti, Gianmarco De Francisci Morales

arXiv:2609.34846v1cs.CYcs.SI

TL;DR

The paper asks whether demographic groups take different routes into political communities, since existing evidence mainly shows which online spaces groups occupy. It uses stratified attention-flow networks to compare Reddit environmental and conspiracy communities, finding that their entry pathways sort users along different demographic axes and at different stages.

  • Problem

    Prior evidence shows demographic groups occupy different online spaces but leaves unclear whether they traverse different communities and information environments before entering politically salient ones.

    Source: §1 · pp. 1–2

  • Method

    The study uses stratified attention-flow networks to trace demographic groups’ transitions across Reddit communities before their first post in environmental or conspiracy communities.

    Source: §2.3 · p. 4, §4.4.3 · p. 13

  • Results

    Conspiracy entry sorts primarily upstream by gender and partisanship, whereas environmental entry sorts primarily downstream by age and affluence.

    Source: §1 · p. 3, §3 · p. 9

  • Takeaways & Limitations

    The stage of demographic divergence appears to reflect whether a community is identity-based or issue-based.

    Source: §3 · p. 9

    The observational pathways describe how demographic groups arrive, not why, and the proposed mechanisms remain interpretive.

    Source: §3 · p. 10

Abstract

from arXiv · show

The impact of online platforms in political mobilization is widely documented, yet it remains unclear how it affects different demographic groups. To shed light on this phenomenon, we examine two contrasting cases: engagement with environmental causes on one side, and with conspiracy theories on the other. Both are well represented on Reddit, allowing us to study the different origins of these groups using a network-based method. By inferring age, gender, affluence, and partisanship of Reddit users, we construct stratified transition networks to compare the entry pathways of different demographic groups toward these communities. We find that demographic differentiation operates differently in these two domains. Entry into conspiracy communities is primarily structured by gender and partisanship: masculine users disproportionately arrive through overtly political and alt-right spaces and share right-wing media sources, whereas feminine users more often pass through esoteric and spiritual subreddits before converging on r/conspiracy. In contrast, environmental communities are differentiated mainly by age and affluence. Affluent users tend to approach environmental subreddits via discussions of individual energy management, technology, and finance, while less affluent users arrive through protest-oriented and climate movement spaces. By comparing these two issue domains, the study shows that sociodemographic sorting does not operate uniformly across polarized topics. Instead, distinct demographic groups build their own paths, shaping both the routes through which they engage with political content and the informational ecosystems that sustain their engagement. Our approach, based on the attention-flow graph, refines our understanding of how different groups become embedded in online political communities.

1 Introduction

The paper asks how demographic groups enter politically salient online communities, extending static accounts of who occupies different spaces to the paths users take. Comparing conspiracy and environmental communities on Reddit, it finds that demographic sorting differs in timing and in the demographic axes involved.

1 Introduction

  • Prior research shows demographic groups occupy different online spaces, but does not establish whether their routes through communities and information environments also differ.The paper treats these pathways as a way to examine demographic sorting before entry into politically salient communities.Source: §1 · pp. 1–2
  • The comparison distinguishes issue-oriented environmental engagement from identity-expressive conspiracy engagement, while recognizing that neither case is a pure type.The paper proposes that demographic sorting may occur at different pathway stages across these community logics.Source: §1 · p. 2
  • The study operationalizes entry as a user’s first post in a target community and traces preceding subreddit transitions with a stratified attention-flow graph.The graph extends the attention-flow framework to age, gender, affluence, and partisanship, and identifies gateways and bridges along users’ paths.Source: §1 · p. 2
  • Conspiracy entry diverges mainly upstream by gender and partisanship, while environmental entry diverges downstream by age and affluence.Masculine and right-leaning users reach conspiracy communities through political and alt-right spaces; feminine users more often pass through esoteric spaces. Affluent and older users approach environmental communities through energy, technology, and finance, while less affluent and younger users arrive through protest and climate-movement spaces.Source: §1 · pp. 2–3

2 Results

Conspiracy and Environment communities are differentiated along different demographic axes and at different stages of entry. The pathways include distinct subreddit routes and shared URL sources across groups.

2.2 Demographic composition

  • Conspiracy entrants are relatively older, more masculine, affluent, and right-leaning; Environment entrants are older, affluent, and comparatively left-leaning.Aggregate overrepresentation is strongest for Environment, Esoterism, and Alt-Right; Conspiracy has weaker overall skew, clearest on age.Source: §2.2 · pp. 3–4, Figure 2 · p. 5

2.1 Attention flow graph

  • Conspiracy sits between Esoteric and Alt-Right clusters, while Environment lies near Radical Left and Alt-Right communities.The graph represents chronological migration of active users between Reddit communities.Source: §2.1 · p. 3, Figure 1 · p. 4

2.3.1 Community-level random walks

  • Masculine users reach Conspiracy through political communities, especially Alt-Right, while feminine users arrive through esoteric communities; Environment’s largest influx is from Radical Left for both genders.A considerable flow of right-wing users enters Conspiracy from predominantly left-wing Esoterism.Source: §2.3.1 · pp. 5–6, Figure 3 · p. 5

2.3.2 Bridges and Gateways

  • Conspiracy differs most across groups in bridges, Environment in gateways; their pathways sort along gender and partisanship versus age and affluence, respectively.Conspiracy differences are mainly upstream, before entry; Environment differences are mainly downstream, after entry.Source: Figure 4 · p. 6, §2.3.2 · p. 6

2.3.3 URL analysis.

  • Before Conspiracy entry, masculine users share right-wing and martial-arts sources, while feminine users share generalist content; Environment URL sources also differ by affluence.Less affluent Environment entrants share protest and climate-movement sources; affluent entrants share established sources including Twitter, YouTube, CNN, and Reuters.Source: Figure 5 · p. 7, §2.3.3 · p. 8

2.3.2 Bridges and Gateways

  • Masculine users more often pass through explicit political subreddits, while feminine users use esoteric bridges; Environment gateways divide by affluence.Affluent users are more connected to energy management, sustainability, and economics communities; less affluent users are more connected to protest and collective-movement communities.Source: §2.3.2 · p. 8, Table 1 · p. 8

3 Discussion

Demographic sorting appears in both Reddit domains, but at different stages and along different axes: before entry in conspiracy communities, and mainly after entry in environmental communities. These patterns are consistent with the contrast between identity-expressive and issue-oriented engagement, but the authors caution that the cases, measures, and observed pathways have limits.

3 Discussion

  • Conspiracy sorting occurs mainly before entry through bridges, organized by gender and partisanship; environmental sorting occurs mainly after entry through gateways, organized by age and affluence.The authors suggest this stage difference reflects community logic: paths to belonging in identity-based communities and orientation toward action in issue-based communities.Source: §3 · p. 9
  • Masculine conspiracy-community entrants traverse political subreddits and right-leaning media, while feminine entrants more often pass through esoteric and spiritual communities before converging on r/conspiracy.The routes differ, but the internal gateway structure is comparatively undifferentiated, with groups converging on r/conspiracy.Source: §3 · p. 9
  • Environmental entrants diverge by action repertoire: affluent and older users approach through personal-responsibility practices, while less affluent and younger users are associated with structural-change and protest framing.The authors suggest personal pathways may be less accessible without purchasing power, and that collectivist framing may resonate more with younger, less affluent users.Source: §3 · p. 9
  • The two cases are imperfect theoretical types: environmental politics can generate collective identities, while conspiracy communities can mobilize around concrete issues.The authors characterize the comparison as a pragmatic compromise between theoretical clarity and complex online political ecosystems.Source: §3 · pp. 9–10
  • Behavioral proxies may understate within-group heterogeneity, and the reconstructed trajectories capture Reddit-visible activity rather than complete exposure or mobilization histories.The measures are most informative for users whose Reddit behavior is typical of their demographic; observed pathways do not establish why groups arrive or whether pathways shape beliefs.Source: §3 · p. 10

4 Methods

The methods build a Reddit activity dataset and use it to support analyses of user profiles and attention-flow pathways. The dataset covers posts from 2019–2023 and applies sampling and activity-quality filters.

4 Methods

  • The methods cover dataset construction, demographic inference, the Stratified Attention Flow Graph, and measures of communities, entrants, gateways, bridges, and shared URLs.The section proceeds from the Reddit dataset and profile inference to the core graph method and its analyses.Source: §4 · p. 10

4.1 Dataset

  • The dataset includes Reddit submissions from 2019–2023, using a random 10% sample of users selected uniformly rather than by activity volume.The authors use submissions as a stronger proxy for subreddit involvement and select the sampling rate to balance representativeness with computational tractability.Source: §4.1 · pp. 10–11
  • After engagement, active-community, and bot filters, the dataset contains 50,360,619 posts from 4,536,459 users across 89,157 subreddits.Filters retain posts scoring above one, require at least 50 distinct monthly posters in a subreddit, and exclude specified high-volume and bot-named users.Source: §4.1 · p. 11

4.2 Inferring Sociodemographics on Reddit

The paper infers subreddit-level social-dimension scores from embedding directions defined by differentiated seed pairs, then maps them to users through posting activity. The resulting user scores are behavioral associations, with age scores checked against self-reported ages.

4.2.1 Social dimension scores.

  • Subreddit embeddings position communities with similar user bases near one another, and social-dimension directions are derived from paired seed communities that differ on a target construct.The method averages top-k seed-pair vector differences and projects each subreddit embedding onto the resulting direction to assign a score.Source: §4.2.1 · p. 11, §4.2 · p. 11

4.2.2 User-level scores.

  • A user’s score for each dimension is the post-weighted average of scores for subreddits where they participate; analysis requires at least five posts in subreddits with embedding scores.Scores cover age, gender, affluence, and partisanship; the analysis restricts the independent embedding set to 8,296 subreddits active in the observation window.Source: §4.2.2 · p. 11
  • The scores represent behavioral associations, not directly measured personal attributes; age scores align with self-reported ages, with older-pole users tending to be over 25 and younger-pole users under 20.Partisanship scores indicate alignment with left- or right-leaning Reddit discourse rather than measured ideology.Source: §4.2.2 · pp. 11–12

4.3 Stratified Attention Flow Graph

The Stratified Attention Flow Graph (S-AFG) conditions Reddit attention flows on sociodemographic dimensions, enabling comparison of how pathways into communities vary across groups.

4.3 Stratified Attention Flow Graph

  • The S-AFG extends the Attention Flow Graph by conditioning attention flows between subreddits on users’ sociodemographic profiles.The construction first builds the AFG as a structural backbone, then stratifies its flows by social dimension.Source: §4.3 · p. 12

4.3.1 Building the AFG.

  • The AFG is a weighted, directed network whose edges represent average attention migration between subreddits over time.The resulting graph is extremely dense, so a disparity filter removes statistically insignificant edges at α = 0.01, leaving 779 021 directed edges over 62 139 nodes in the giant component.Source: §4.3.1 · p. 12

4.3.2 Incorporating Sociodemographics.

  • For each social dimension, user contributions are weighted by their dimension scores, then aggregated over time into a separate flow network.The stratified network is reweighted by corresponding AFG edge weights and restricted to edges present in the original graph.Source: §4.3.2 · p. 12
  • Because scores can be positive or negative, each dimension’s stratified network is split into flows associated with opposite ends of that social dimension.For age, the positive component represents users toward the older end and the negative component represents younger users; the framework supports comparing gateways and bridges across groups.Source: §4.3.2 · pp. 12–13

4.4 Measures on the (S-)AFG

The paper combines community detection, pre-entry demographic profiling, pathway rankings, and prior URL sharing to characterize how users enter Reddit communities.

4.4 Measures on the (S-)AFG

  • Four measures on the (S-)AFG cover community detection, entrant profiling, gateway and bridge identification, and shared URLs before community entry.Together, they examine community structure, users’ prior positions, entry pathways, and information environments.Source: §4.4 · p. 13

4.4.1 Community Detection.

  • Infomap detects 4,083 communities on the filtered AFG; five selected communities spanning conspiratorial, alt-right, radical-left, and environmental topics anchor subsequent analyses.Infomap is chosen over stochastic block models for computational scalability at this scale.Source: §4.4.1 · p. 13

4.4.2 Sociodemographics of community entrants.

  • Entrant sociodemographic scores use only posts before users’ first participation in a target community, excluding activity within that community.This restriction is intended to measure users’ prior positioning in the broader attention network.Source: §4.4.2 · p. 13

4.4.3 Gateways and Bridges.

  • Personalized PageRank ranks gateway subreddits as likely entry points from outside a target and, on the transposed graph, ranks bridges along incoming pathways.The comparison across demographic groups uses weighted Kendall’s τ, which gives greater importance to highly ranked nodes.Source: §4.4.3 · pp. 13–14

4.4.4 Shared URLs Prior to Community Entry.

  • The shared-URL analysis includes only URLs users posted before their first target-community participation and excludes posts within that community.These URLs characterize prior information environments and complement Reddit interaction patterns.Source: §4.4.4 · p. 14

6 Ethics statement

The study analyzes publicly available Reddit data without direct human-subject interaction or collection of personally identifiable information.

6 Ethics statement

  • The analysis uses publicly available data from Reddit collected via Pushshift and involved no direct interaction with human subjects.Source: §6 · p. 14
  • Sociodemographic attributes were statistically inferred from posting behavior at the aggregate level, and individuals were not identified or profiled in reported results.Analyses were conducted at the community and group level.Source: §6 · p. 14
  • The research was determined exempt from IRB review as publicly available data research with no possibility of identifying individual subjects.Source: §6 · p. 14

S1 Network construction

The supplement details construction of the Attention Flow Graph, its sparsification, and descriptive checks of the resulting network and selected communities.

S1.1 Attention Flow Graph

  • The AFG aggregates users’ changes in subreddit attention into directed flows between communities, then combines those flows across users and time.The graph’s edge weights represent attention transferred from one subreddit to another.Source: S1.1 Attention Flow Graph · p. 18

S1.3 Statistics on the AFG

S1.2 The Disparity Filter

  • The Disparity Filter retains edges whose local weight heterogeneity is statistically significant under a random-allocation null model.For directed networks, incoming and outgoing edges are tested separately, and an edge is kept if significant for at least one endpoint.Source: S1.2 The Disparity Filter · p. 19

S1.3 Statistics on the AFG

  • The supplement reports weight distributions before and after filtering, a power-law-like community-size distribution, and summary statistics for the five selected communities.Most detected communities have about 10 subreddits, while a few are larger; Table S1 reports seed subreddit, node count, and intra-community edge count.Source: S1.3 Statistics on the AFG · p. 19, Table S1 · p. 19, Figure S2 · p. 20

S2 Sociodemographic scores

Supplementary analyses describe the sociodemographic score distributions and validate projected age against self-declared age. Seed subreddits show clearer separation on age and partisanship than on gender and affluence.

S2 Sociodemographic scores

  • Figure S3 presents subreddit-level and projected user-level score distributions across age, gender, affluence, and partisanship.Scores are shown in standard deviations from each dimension’s mean.Source: S2 Sociodemographic scores · p. 21, Figure S3 · p. 22
  • Projected age scores broadly track self-declared age, with higher projected scores corresponding on average to older users.The comparison reports median self-declared age for projected-score bins containing at least three users.Source: S2 Sociodemographic scores · p. 21, Figure S4 · p. 22
  • Seed subreddits show clear separation on age and partisanship, but weaker or no clear separation on gender and affluence.The expected groups are not strongly overrepresented in r/AskMen or r/vagabond.Source: Figure S5 · p. 23

S3 Extended results on reachability, rankings, and URLs

The supplementary analyses report cross-community reachability, differences in group gateway and bridge rankings, and external domains shared before entry into the communities under study.

S3 Extended results on reachability, rankings, and URLs

S4 Bridges and gateways full rankings

The supplementary tables provide full gateway and bridge rankings for multiple communities across both poles of every sociodemographic dimension.

S4 Bridges and gateways full rankings

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