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  • Featured in Physics
  • Open Access

Decoding Social Integration in Schooling Fish Using Closed-Loop Real-Virtual Interactions

Zhen Kang1,2, Ramón Escobedo2,3,4,5, Maud Combe2, Stéphane Sanchez4, Clément Sire3, and Guy Theraulaz2,*

  • *Contact author: guy.theraulaz@univ-tlse3.fr
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PRX Life 4, 043007 – Published 29 October, 2026

DOI: https://doi.org/10.1103/18qw-sfyd

Abstract

Collective motion in animal groups emerges from local interactions, yet how individuals select and integrate social information remains poorly understood. In schooling fish, inferring which neighbors drive an individual's behavior at any given moment is extremely challenging because the analysis of trajectories alone does not unambiguously reveal the underlying causal interactions that generate the observed motion. Here, we used a closed-loop virtual-reality system in which a single real rummy-nose tetra Hemigrammus rhodostomus interacted in real time with four model-driven virtual conspecifics whose interaction rules could be precisely controlled. By systematically varying the number of influential neighbors of the virtual fish and combining experiments with simulations, we quantified how social information filtering shapes individual and collective dynamics. Collective coordination increased with stronger social coupling, but analyses of kinematics, spatial organization, correlations, and turning dynamics consistently showed that the real fish behaved as if it were responding primarily to the single most influential neighbor, whose identity could change over time. These results demonstrate that selective interaction with the most influential neighbor is sufficient to sustain coordinated group motion and highlight the power of biohybrid closed-loop experiments to reveal causal mechanisms of collective behavior.

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Schooling Fish May Have Just One Influencer

Published 29 October, 2026

By studying a real fish swimming among virtual fish, researchers uncover the rules that a fish follows when schooling.

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PRX Life 4, 043007– Published 29 October, 2026
  • Received 11 March 2026
  • Accepted 18 August 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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