Symmetry Breaking in Pedestrian Dynamics

TL;DR

This paper investigates how pedestrians develop social norms for passing directions, showing that collective behavior and lane formation emerge when individuals are attentive to others' choices, influencing crowd dynamics.

Contribution

It models the emergence of social norms in pedestrian passing behavior through a phase diagram, highlighting the role of attentiveness in symmetry breaking and lane formation.

Findings

Social norms can emerge if pedestrians are attentive to others' choices.

Lane formation results from symmetry breaking in pedestrian flows.

Collective behavior significantly influences crowd movement dynamics.

Abstract

When two pedestrians travelling in opposite directions approach one another, each must decide on which side (the left or the right) they will attempt to pass. If both make the same choice then passing can be completed with ease, while if they make opposite choices an embarrassing stand-off or collision can occur. Pedestrians who encounter each other frequently can establish "social norms" that bias this decision. In this study we investigate the effect of binary decision-making by pedestrians when passing on the dynamics of pedestrian flows in order to study the emergence of a social norm in crowds with a mixture of individual biases. Such a situation may arise, for instance, when individuals from different communities mix at a large sporting event or at transport hubs. We construct a phase diagram that shows that a social norm can still emerge provided pedestrians are sufficiently attentive to the choices of others in the crowd. We show that this collective behaviour has the potential to greatly influence the dynamics of pedestrians, including the breaking of symmetry by the formation of lanes.