On an evening in January A.D. 532, pandemonium broke out in the Constantinople Hippodrome, a U-shaped chariot racetrack surrounded by stadium stands. Two factions, the Greens and Blues—the predecessors of today’s soccer hooligans—broke into a fight. When the rest of the spectators dashed to escape, many became trapped by the rushing crowd, couldn’t reach the exits, and were trampled and killed. That incident was the start of the Nika riots that almost ended the rule of Eastern Roman emperor Justinian the Great.
Fifteen hundred years later, not much has changed. We still have stampedes, and still can’t get out of enclosed spaces properly. Since 2009, there have been fatal stadium stampedes in Morocco, Cote d’Ivoire, Bangkok, and Egypt. In their study of escape panic, Swiss physicist and sociologist Dirk Helbing concluded together with his colleagues that, “physical interactions in [a] jammed crowd add up and cause dangerous pressures… which can bend steel barriers or push down brick walls.”
Some animals evolved to clump together when threatened because it increased their chances of survival. “Predators have the ability to focus and concentrate on individual prey,” says Ralph Tollrian, a professor in Germany who has spent his career studying the predator confusion effect. “When they handle one prey, they can’t hunt the next.” Birds and fish form groups that move chaotically in the presence of a predator, giving it “cognitive overload,” says Randy Olson, who builds computer models of predator and prey behavior at Michigan State University. The predator’s cognitive overload can be so strong that it may give up on its pursuit entirely. “A confused predator can sometimes become frustrated and not hunt at all,” Tollrian says
Via Alessandro Cerboni