A Simulation Framework for Studying Recommendation-Network Co-evolution in Social Platforms

Fuente: arXiv
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Main Authors: Koley, Gaurav, Digrajkar, Sanika
Format: Preprint
Published: 2025
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author Koley, Gaurav
Digrajkar, Sanika
author_facet Koley, Gaurav
Digrajkar, Sanika
contents Studying how recommendation systems reshape social networks is difficult on live platforms: confounds abound, and controlled experiments risk user harm. We present an agent-based simulator where content production, tie formation, and a graph attention network (GAT) recommender co-evolve in a closed loop. We calibrate parameters using Mastodon data and validate out-of-sample against Bluesky (4--6\% error on structural metrics; 10--15\% on held-out temporal splits). Across 18 configurations at 100 agents, we find that \emph{activation timing} affects outcomes: introducing recommendations at $t=10$ vs.\ $t=40$ decreases transitivity by 10\% while engagement differs by $<$8\%. Delaying activation increases content diversity by 9\% while reducing modularity by 4\%. Scaling experiments ($n$ up to 5,000) show the effect persists but attenuates. Jacobian analysis confirms local stability under bounded reactance parameters. We release configuration schemas and reproduction scripts.
format Preprint
id arxiv_https___arxiv_org_abs_2512_10106
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Simulation Framework for Studying Recommendation-Network Co-evolution in Social Platforms
Koley, Gaurav
Digrajkar, Sanika
Social and Information Networks
Multiagent Systems
Studying how recommendation systems reshape social networks is difficult on live platforms: confounds abound, and controlled experiments risk user harm. We present an agent-based simulator where content production, tie formation, and a graph attention network (GAT) recommender co-evolve in a closed loop. We calibrate parameters using Mastodon data and validate out-of-sample against Bluesky (4--6\% error on structural metrics; 10--15\% on held-out temporal splits). Across 18 configurations at 100 agents, we find that \emph{activation timing} affects outcomes: introducing recommendations at $t=10$ vs.\ $t=40$ decreases transitivity by 10\% while engagement differs by $<$8\%. Delaying activation increases content diversity by 9\% while reducing modularity by 4\%. Scaling experiments ($n$ up to 5,000) show the effect persists but attenuates. Jacobian analysis confirms local stability under bounded reactance parameters. We release configuration schemas and reproduction scripts.
title A Simulation Framework for Studying Recommendation-Network Co-evolution in Social Platforms
topic Social and Information Networks
Multiagent Systems
url https://arxiv.org/abs/2512.10106