Humans are largely impredictable, as our daily experience teaches us. Still, it has been thought for a while that, far from being completely erratic, the dynamics of pedestrian crowds may be predicted to some extent. In fact, some similarties have even been pointed out between the dynamics of dense crowds and those of granular materials.
In this paper, this analogy is put to the test in a specific situation, the crossing of a static crowd by an intruder.
Here are the responses that were observed: