Behind the Love Parade Tragedy: The Psychology of Stampedes

Terrible news today from the German city of Duisburg, where a summer carnival called the “Love Parade” has been stricken by tragedy. According to breaking news reports, a crowd of revelers inside a tunnel became overcrowded and panicked, causing a stampede that has left at least 15 dead.

There are multiple layers of dark irony in this kind of needless death — for one thing, that a gathering called together in the name of peace could result in such a horrific toll; for another, that in the 21st century simple fear by itself is able to cause mass casualties. But that’s the paradox of terror: a response that evolved to keep us safe can itself pose a terrible danger, rising up at the most inappropriate times. If anything, the advent of modern technology seems to have left us even more vulnerable to fatal stampedes, as mass transportation and instant communication make it easier to bring large crowds together. But this kind of tragedy has a long history. As I write in Extreme Fear,

In many of the past century’s most deadly fires the leading cause of death was not burning or smoke inhalation but being crushed to death in a panicked stampede. There doesn’t even need to be an actual threat, so long as the crowd believes that there is one. Among the worst mass fatalities during the German bombing campaign against London in World War II was an incident that took place when a crowd of civilians lined up outside the shelter in the Bethnal Green Underground Station. An air-raid siren had sounded several minutes before, but the crowd didn’t panic until a nearby anti-aircraft battery fired a salvo of rockets. A woman carrying an infant stumbled at the top of the steps leading down into the station; the surge of the crowd behind them caused hundreds more to fall.  Amid the din of the guns and rockets, no one could hear the screams of the men, women, and children being crushed to death. Those at the back, unable to move forward and fearing that they were being forcibly excluded from safety, pushed harder. Within 15 minutes, 173 people had died. In a twist of grim irony, not a single bomb had fallen.

What causes a crowd of peaceful, if anxious, individuals to suddenly become swept into a blind panic? As I’ve written earlier, the literature on the psychology of panic is as yet rather thin, but researchers have recently begun to understand the underlying mechanisms.

Just as a forest fire needs a critical density of dry timber in order to reach the blowout stage, a crowd must reach a critical density in order to become dangerous. Crowds will continue to grow in size or density until there are about 10 people per square meter — that’s 2,600 people in an area the size of a tennis court. From here, psychologists who have studied mass panic distinguish between two major ways that things can go wrong. “Unidirectional stampedes” occur when a crowd reacts to a sudden positive or negative change in force. A positive change in force might occur when a crowd is stopped by a barricade or a narrowing in a passageway; a negative force is the release of constraining pressure, as for instance might occur when a gate is opened. At Bethnel Green, the falling mother blocked the crowd and created a positive force that stopped the crowd behind her. Based on preliminary accounts from Duisberg, where the fatalities occurred near an entrance gate, a similar dynamic may have been at work.

The second kind of disaster is a “turbulent stampede” that takes place when two crowds merge from different directions or a stationary crowd is induced to panic.

Once panic takes hold, individual free will goes out the window and the mass as a whole becomes subject to a collective crowd psychology. Not only do people in such situations show a tendency to mimic the behavior of those around them, but the sheer physical force of the crowd can become irresistible, capable of bending sturdy steel stanchions and knocking down brick walls. One particularly gruesome aspect of stampedes is that these factors can cause victims to overlook perfectly good exits, as for instance occurred in the Station nightclub fire.

In the event that you find yourself in a stampede situation? Once the stampede has begun, very little, due to the enormous forces at work. Your best bet is to stay alert whenever in a large crowd. Take note of exits and other escape routes, and when the density becomes high enough to seem dangerous, move away from the center. Ask yourself: do I really need to be here? Perhaps the greatest irony of stampedes is that, in retrospect, the attraction that brought the crowd together seldom seems important enough to merit any deaths at all.