Collective movements of pedestrians: How we can learn from simple experiments with non-human (ant) crowds

Abstract

IntroductionUnderstanding collective behavior of moving organisms and how interactions between individuals govern their collective motion has triggered a growing number of studies. Similarities have been observed between the scale-free behavioral aspects of various systems (i.e. groups of fish, ants, and mammals). Investigation of such connections between the collective motion of non-human organisms and that of humans however, has been relatively scarce. The problem demands for particular attention in the context of emergency escape motion for which innovative experimentation with panicking ants has been recently employed as a relatively inexpensive and non-invasive approach. However, little empirical evidence has been provided as to the relevance and reliability of this approach as a model of human behaviour.MethodsThis study explores pioneer experiments of emergency escape to tackle this question and to connect two forms of experimental observations that investigate the collective movement at macroscopic level. A large number of experiments with human and panicking ants are conducted representing the escape behavior of these systems in crowded spaces. The experiments share similar architectural structures in which two streams of crowd flow merge with one another. Measures such as discharge flow rates and the probability distribution of passage headways are extracted and compared between the two systems.FindingsOur findings displayed an unexpected degree of similarity between the collective patterns emerged from both observation types, particularly based on aggregate measures. Experiments with ants and humans commonly indicated how significantly the efficiency of motion and the rate of discharge depend on the architectural design of the movement environment.Practical applicationsOur findings contribute to the accumulation of evidence needed to identify the boarders of applicability of experimentation with crowds of non-human entities as models of human collective motion as well as the level of measurements (i.e. macroscopic or microscopic) and the type of contexts at which reliable inferences can be drawn. This particularly has implications in the context of experimenting evacuation behaviour for which recruiting human subjects may face ethical restrictions. The findings, at minimum, offer promise as to the potential benefit of piloting such experiments with non-human crowds, thereby forming better-informed hypotheses.

Traffic Flow of Merging Pedestrian Crowds: How Architectural Design Affects Collective Movement Efficiency

“…Based on the investigation of the literature related to the notion of geometric designs, particularly the impact of conflicting geometries on crowd dynamic, a number of studies ( 11 , 31 , 32 ) explored the effect of corridor configurations in merging passage using non-human subjects. These experiments have been considered as a proximate model of the scale-free behavior of humans.…”

Pedestrian flow characteristics through different angled bends: Exploring the spatial variation of velocity

“…Different geometrical and architectural configurations with different level of complexities, e.g., exits and entrances [ 13 – 17 ], straight corridors [ 18 – 20 ], crossing [ 21 – 25 ], merging [ 26 – 30 ], and turning [ 31 – 34 ] configurations, have been explored in such previous studies using controlled experiments conducted with human subjects. Not only humans, but non-human biological entities, e.g., ants, have also been used to explore the evacuation performance of different geometrical settings under panic conditions [ 35 – 37 ]. For the design purposes that ensure the safety of crowds and efficiency of crowd flows at general bottleneck scenarios, e.g., exit doors and corridors, several studies have indicated that there is a direct relationship between pedestrian flow and bottleneck width, i.e., increasing pedestrian flows with increasing the bottleneck width and thereby decrease in evacuation time [ 17 , 38 – 41 ].…”

Heterogeneity-induced lane and band formation in self-driven particle systems

“…The microscopic interaction rules initiate motility-induced phase separation from disordered states to non-uniform macroscopic patterns displaying order (at least partially) 20,21 . Pedestrian and vehicle flows are also systems of interacting self-driven agents that can exhibit phase transitions and self-organisation [22][23][24][25][26] . Indeed, pedestrians and drivers interact locally with their environment and the neighbourhood and have by the way density-dependent motility parameters.…”