Inspired by earlier computer simulations that predicted a symmetry-breaking phenomenon when panicked humans escape from a room with two equivalent exits, a team of researchers led by E. Altschuler carried out the two experiments described above, which revealed the symmetry-breaking effect in the leafcutter ant Atta insular in the presence of insect repellent.
[1] Another team of researchers led by Geng Li investigated the influence of the ant group's density on the symmetry breaking.
[2] The common idea is that the action of injecting the insect repellent induces herd behavior in the ants.
Altshuler and coworkers were able to reproduce their symmetry-breaking experiments previously done in ants in humans, using a simplified version of the theoretical model proposed earlier by Helbing et al.[3] based on the fact that walkers tend to follow the general direction of motion of their neighbors ("Vicsek's rule"[4]), and such herd behavior increases as the so-called "panic parameter" increases.
[2] The pheromone mechanism shares the key elements of the previous models: stressed ants tend to "follow the crowd".