Group dynamics shape contagion onsets and multistable active phases under collective reinforcement

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Lamata-Otín, Santiago, Malizia, Federico, Keating, Leah A., St-Onge, Guillaume, Latora, Vito, Gómez-Gardeñes, Jesús, Hébert-Dufresne, Laurent
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917369657425920
author Lamata-Otín, Santiago
Malizia, Federico
Keating, Leah A.
St-Onge, Guillaume
Latora, Vito
Gómez-Gardeñes, Jesús
Hébert-Dufresne, Laurent
author_facet Lamata-Otín, Santiago
Malizia, Federico
Keating, Leah A.
St-Onge, Guillaume
Latora, Vito
Gómez-Gardeñes, Jesús
Hébert-Dufresne, Laurent
contents Group-based reinforcement can induce discontinuous transitions from inactive to active phases in higher-order contagion models. However, these results are typically obtained on static interaction structures or within mean-field approximations that neglect temporal changes in group composition. Here, we show that group dynamics is not a secondary effect but a central aspect that determines the macroscopic transition class of higher-order contagion processes. We develop an analytically tractable approximate master equation model that effectively interpolates between quenched and mean-field limits through a group composition turnover rate. Our results reveal the rich impact of time-varying structures: it can induce discontinuous phase transition, broaden the bistable region, and at the same time promote or suppress contagion near criticality. Moreover, when real-world turnover rates and group-size heterogeneity are taken into account, the system exhibits a qualitatively richer phase diagram with four distinct dynamical phases, combining continuous or discontinuous transitions with localized or delocalized activity. In localized regimes, we uncover multistable active phases with multiple coexisting active states, which are observed in neither the annealed nor the quenched limits, and extend classical absorbing-active bistability. Finally, we demonstrate that the emergence of discontinuous transitions in real-world systems requires stronger nonlinear reinforcement than previously thought, indicating that simulations in static structures can yield qualitatively misleading predictions.
format Preprint
id arxiv_https___arxiv_org_abs_2603_28566
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Group dynamics shape contagion onsets and multistable active phases under collective reinforcement
Lamata-Otín, Santiago
Malizia, Federico
Keating, Leah A.
St-Onge, Guillaume
Latora, Vito
Gómez-Gardeñes, Jesús
Hébert-Dufresne, Laurent
Physics and Society
Group-based reinforcement can induce discontinuous transitions from inactive to active phases in higher-order contagion models. However, these results are typically obtained on static interaction structures or within mean-field approximations that neglect temporal changes in group composition. Here, we show that group dynamics is not a secondary effect but a central aspect that determines the macroscopic transition class of higher-order contagion processes. We develop an analytically tractable approximate master equation model that effectively interpolates between quenched and mean-field limits through a group composition turnover rate. Our results reveal the rich impact of time-varying structures: it can induce discontinuous phase transition, broaden the bistable region, and at the same time promote or suppress contagion near criticality. Moreover, when real-world turnover rates and group-size heterogeneity are taken into account, the system exhibits a qualitatively richer phase diagram with four distinct dynamical phases, combining continuous or discontinuous transitions with localized or delocalized activity. In localized regimes, we uncover multistable active phases with multiple coexisting active states, which are observed in neither the annealed nor the quenched limits, and extend classical absorbing-active bistability. Finally, we demonstrate that the emergence of discontinuous transitions in real-world systems requires stronger nonlinear reinforcement than previously thought, indicating that simulations in static structures can yield qualitatively misleading predictions.
title Group dynamics shape contagion onsets and multistable active phases under collective reinforcement
topic Physics and Society
url https://arxiv.org/abs/2603.28566