1374, thousands of people across Europe were infected with the compulsion to dance to the point of exhaustion and death. Turns out, it was just another case of people being slaves to trends, even trends that were harmful. Look at those fucking hipsters.

The phenomenon known as St. Vitus' Dance was originally thought to be an outbreak of a neurological disorder called Syndenham chorea, which is an infection of the central nervous system that causes jerking of the appendages and face. (I'd imagine that Syndenham chorea would be a nightmare to come down with at a wedding, because how would anyone know you were sick and not just another drunken idiot who doesn't understand that Journey is not an appropriate soundtrack for crumping? But I digress.)

It turns out that what historians now refer to as St. Vitus' Dance may have actually been a case of mass hysteria and social contagion similar to what causes people to yawn when they see others yawning. The same principle that caused all those Europeans to boogie themselves to oblivion almost 700 years ago causes us to similarly mimic the emotions and movements of others.

John Cacioppo, director of the University of Chicago's Center for Cognitive and Social Neuroscience, said, "A couple of different processes contribute to something like this. One is peer pressure. If you're sittng in a setting and everyone is acting in a certain way, you do the same thing."

There's also a concept called pluralistic ignorance, which Cacioppo described as, "I would stop, but I don't see anyone else stopping."

I didn't realize that Gloria Estefan was being literal when she warned America that the rhythm was going to get us. Not only is the rhythm going to get us, it's already gotten us.

Ancient Dancing Outbreak Believed to be a Case of Social Contagion [ABC]