Dancing Plagues and Witch Hunts The Strange Power of Mass Hysteria

In the winter of 1374, along the banks of the Rhine River, something extraordinary began to happen. People started dancing. Not in celebration, not in worship — but compulsively, desperately, without stopping. Hundreds of men and women writhed and convulsed through the streets of Aachen, their bodies seemingly hijacked by an invisible force. Some danced until their feet bled. Some collapsed from exhaustion. Some died. And the strangest part? The outbreak spread. Town to town, body to body, as though the dancing itself were contagious.

A century and a half later, in the summer of 1518, it happened again in Strasbourg. A woman named Frau Troffea walked into the street and began to dance alone. Within a week, thirty-four people had joined her. Within a month, the number had swelled to four hundred. The local authorities, baffled and desperate, actually prescribed more dancing — hiring musicians to play, hoping that exhaustion would eventually win. It didn't work. People died of stroke, heart attack, and sheer physical collapse. And still the dancing spread.

We look back at episodes like these and feel a comfortable distance. Those were medieval people, we tell ourselves. Superstitious, uneducated, living in a pre-scientific age. The kind of collective madness that sweeps through a crowd and makes people dance themselves to death simply couldn't happen to us. We know better now. We have the internet. We have science. We have the ability to verify a claim before we share it.

And yet.

The history of human civilization is littered with moments when large groups of perfectly ordinary people believed the same impossible thing — and acted on that belief with devastating consequences. The tulip traders of 17th-century Holland who mortgaged their homes for flower bulbs. The citizens of Salem, Massachusetts, who hanged their neighbors on the testimony of children. The investors of the South Sea Bubble who convinced themselves that limitless wealth was one subscription away.