Collective motion of self-propelled particles with selective interactions regulated by Motion Salience Threshold

We propose a collective motion model incorporating selective interactions through a Motion Salience Threshold (MST) mechanism, where particles dynamically switch between an active state responding to significant motion cues and an inactive state aligning with local average orientation. This selective interaction mechanism enables particles to filter out minor fluctuations while maintaining sensitivity to meaningful changes in their neighbors’ motion states. Through extensive numerical simulations and statistical analysis, we reveal that this threshold-based selection fundamentally alters both the system’s collective states and the nature of its phase transitions. When varying noise intensity, higher thresholds promote robust collective order by favoring averaging-based dynamics, leading to second-order phase transitions confirmed by finite-size scaling analysis. In contrast, varying the threshold itself induces first-order transitions with clear hysteresis at low noise, which transform into continuous transitions as noise increases. These findings demonstrate how selective interactions regulated by motion-based thresholds shape collective behavior through distinct dynamical mechanisms, enriching our understanding of self-organized systems.