How singular is a pedestrian, as compared to a vibrated grain or a self-propelled particle?
Despite the complexity of the human mind, pedestrians often seem to move fairly predictibly. Even more so when the crowd is dense and volume exclusion constraints restrict possible move. In this situation, similarities have been pointed at between the crowd's response and that of granular matter.
More generally, the equations often posited for pedestrian dynamics bear striking resemblance with those for simpler active particles, so that one may wonder whether these equations are actually adequate to describe the decision-making process.
An introductory discussion along these lines is proposed in a
submitted to the Proceedings of the 2019 Traffic & Granular Flow conference.