The Influence of Explicit and Covert Leaders on Human Crowd Motion

Previous research has suggested that some positions in human crowds are more influential than others. The present study aims to manipulate the influence networks in real human crowds by specifying the causal relationship among some pedestrians. We strategically placed covert or explicit leaders (confederates) in a group of walking pedestrians, instructed them to change walking direction (heading) on a signal, and tested their influence on collective motion. We reconstructed visual influence networks from video data and analyzed the effect of these leaders on the movements of other pedestrians. Our results suggest that both covert and explicit leaders in influential positions can steer and split a crowd, but explicit leaders change the network topology and are significantly more influential than their covert counterparts. The results have potential applications to directing emergency evacuations.