I’d never heard of St. Vitus’ Dance until I read an ABC News story recently about its anniversary:

St. Vitus’ Dance, back in 1374, groups of people — sometimes thousands at a time — started dancing uncontrollably. It continued for days, and in some cases, weeks and months. Some people reportedly danced until they collapsed from exhaustion or even death, while others suffered heart attacks and broken bones

Wow. I’ve danced til hot, sweaty and exhausted — but dancing yourself to death? That’s one you don’t hear often.
But the part that’s really interesting to me is that it was uncontrollable, perhaps contagious like feeling compelled to yawn when you see someone else doing it.

“We tend to imitate body language and the emotional state of people that we’re with, and we’re not aware of it,” Fowler said. (James Fowler, professor of medical genetics and political science at the University of California, San Diego. )

This seems like one more reason people might have such a fantastic experience at big festivals like Burning Man, Bonnaroo or New Orleans Jazz Fest — if you’re surrounded by thousands of other people who’ve gathered for the express purpose of having a good time, you’ll feel and imitate the emotional state of those happy partiers around you.
[youtube=http://www.youtube.com/watch?v=fIBdT5TU8Bs]
But even if you aren’t called to uncontrollable dance, there’s a moral to the story here. You’re imitating the emotional state of those around you, so choose your companions wisely.

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.”
Fowler also said other things are socially contagious, such as obesity, happiness and loneliness.
“Someone has an intense emotional experience, and because of its intensity, passes it on to other people,” Fowler explained.

I hope you spend your Fourth of July with happy people — and if you find yourself dancing until you’re injured, seek medical attention immediately.