Science struggles to find what triggers human stampedes
First- responders are focused on finding and treating the injured
International health organizations have to recognize that this is an important type of disaster.
A stampede Thursday near Mecca during the peak of the annual hajj pilgrimage is just the latest in a regular string of such events at the site — but it’s the deadliest one in 25 years.
It’s hard to imagine how a crowd — especially one gathered for a peaceful religious rite — can turn so deadly. But the phenomenon is so common that experts in crowd management are consulted for most highly trafficked events.
While many researchers focus on how to prevent stampedes by keeping spaces from getting overcrowded, there has been little research on what happens once a stampede starts — or why, exactly, they begin.
In 2010, a review of all available literature on stampedes found that, despite efforts, they’re on the rise. But the researchers noted that little was known about the actual triggers for these events. First- responders, they said, were rightly focused on finding and treating the injured, not on taking detailed notes of their observations of the stampede.
“International health organizations have to recognize that this is an important type of disaster,” Edbert Hsu, associate professor of emergency medicine at Johns Hopkins, said in a statement at the time.
“If they made it a protocol to send someone to a trampling disaster quickly to see what happened, we would have detailed reports we could use to compare and contrast. Without ( those reports), we won’t really understand what we’re dealing with.”
Mechanically, stampedes are tragically simplistic. Once people are pushed tightly against one another ( about seven people per 10 square feet of space, according to one study) it’s vital that those in the front keep moving as quickly as those behind them. Otherwise, the people in the back — unable to see the front of the crowd — will move forward seeking more space, assuming that those in the front will continue to move to make way for them.
If for some reason the paces become mismatched — because something is blocking the front of the group, or a rumour is spreading in the back that people are being crushed, causing folks to speed up — the front of the group gets squeezed, sometimes producing enough force to crush people where they stand.
It’s likely the most deadly stampedes begin with a handful of deaths, caused by the sheer force of the tightly packed group, that then cause mass panic. Smaller stampedes might not be fuelled by panic — people can be crushed by the weight of those around them without anyone consciously surging forward.
In fact, experts have argued that blaming the behaviour of the crowd is a mistake, since most stampedes probably can be boiled down to the physical limits of their location. Even stampedes that occur at rowdier events such as soccer games, Black Friday sales or music festivals are more likely a result of physical strain more so than any human behaviour.
But when people do get panicked, it doesn’t help. In a tightly packed crowd, we’re victims of our own biology. The typical “fight or flight” response, where one feels a surge of adrenalin, is anything but helpful.
If the thousands of people vying for space could be calm and collected, stampedes of this magnitude simply wouldn’t occur. But, faced with death, most will be slave to a racing heartbeat and hyperventilation — and an urge to run for safety at any cost.
In the modern world, it’s more possible than ever for massive crowds to gather. People can fly in from all over the world to join in a religious ceremony or catch a glimpse of a leader. And for now, stampedes remain a horrifying possibility at every such gathering.