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BP: Fachverband Biologische Physik
BP 22: Statistical Physics of Biological Systems I (joint session BP/DY)
BP 22.4: Talk
Thursday, March 30, 2023, 10:15–10:30, TOE 317
Selective alignment force in schooling fish linked to leader-follower interactions given by relative speeds of neighbours — •Andreu Puy1, Palina Bartashevich2,3, and Pawel Romanczuk2,3 — 1Departament de Física, Universitat Politècnica de Catalunya, Barcelona, Spain — 2Institute for Theoretical Biology, Humboldt-Universität zu Berlin, Germany — 3Excellence Cluster Science of Intelligence, Technische Universität Berlin, Germany
Collective motion is commonly assumed to emerge when individuals in a group interact with neighbours via some combination of attraction, repulsion and alignment forces. Alignment has been the most elusive and controversial force to study in experimental setups, with previous works differing about its existence. Here we revisit the topic by introducing a force map technique depending on the relative velocities of neighbours. In contrast to commonly used force maps, our technique demonstrates evidence for experimental data of schooling fish of a selective alignment force when individuals move at slower speeds than their neighbours and an antialignment force when they move at higher speeds. We employ a simple model with alignment to demonstrate the validity and robustness of the proposed force map. Including a selective interaction where individuals only interact with faster neighbours allowed us to reproduce the alignment interactions in the experimental data. Finally, we link this idea to leader-follower interactions, justifying that faster individuals act as leaders with respect to their neighbours.