Faster-is-slower effect in escaping ants revisited: Ants do not behave like humans

TL;DR

This study investigates ant evacuation behavior under stress, revealing that ants do not exhibit the faster-is-slower effect seen in humans, due to their uniform distribution and lower backward step probability, challenging existing models.

Contribution

The paper demonstrates that ants evacuate efficiently without density buildup near exits and do not follow the social force model predictions, highlighting key behavioral differences from humans.

Findings

Ants are uniformly distributed during evacuation.

Lower backward step probability correlates with faster evacuation.

The faster-is-slower effect does not apply to ants.

Abstract

In this work we studied the trajectories, velocities and densities of ants when egressing under controlled levels of stress produced by a chemical repellent at different concentrations. We found that, unlike other animals escaping under life-and-death conditions and pedestrian simulations, ants do not produce a higher density zone near the exit door. Instead, ants are uniformly distributed over the available space allowing for efficient evacuations. Consequently, the faster-is-slower effect observed in ants (Soria et al., 2012) is clearly of a different nature to that predicted by de social force model. In the case of ants, the minimum evacuation time is correlated with the lower probability of taking backward steps. Thus, as biological model ants have important differences that make their use inadvisable for the design of human facilities.