I've recently been listening to snippets of Malcolm Gladwell's The Tipping Point on Radio For the Blind. They just completed a segment on mass hysteria, and that got me thinking about my one experience with the phenomenon.
When Sarah and I lived in Brooklyn we would make frequent Sunday treks into Chinatown for a dim sum brunch. The restaurant we went to (its name escapes me at the moment) was excellent and enormous. Upon entering off the street one would ride a golden escalator up two stories to an ornately decorated dining room the size of a football field that held at least a thousand diners. There guests were seated by hosts and hostesses with radios at one of dozens of large round tables, often with another group (I remember once having a conversation with a Chinese-American family from New Jersey who also regularly made the trek and being mildly stunned as their 4 year old daughter happily slurped up chickens' feet).
One Sunday we went with a friend from out of town. We were seated at table near the edge of the room. We had just completed our meal when a commotion occurred in the middle of the room. A woman quickly stood up covering her face with a handkerchief, yelled something, and began running towards the door. Others around her also started running. We watched in confusion as the wave of panic radiated out from the middle of the room towards us, and then we were running too, out an emergency exit, down three flights of stairs, along an underground tunnel, and then up and out onto the street.
We all stood around trying to understand what happened. We tried to talk to other customers, but no one near us spoke English. Soon, fire trucks arrived. The cooks on the second floor were leaning out the kitchen windows, laughing and talking, clearly unconcerned. Finally, we asked a fireman what had happened, and he said they hadn't found anything. Eventually we left. None of the customers that day paid. The restaurant certainly lost tens of thousands of dollars.
I have no idea what prompted that first woman to run. Perhaps there was some small, real event, or perhaps it was completely imagined, but it started a chain reaction in which the vast majority of people were responding solely to the responses of others. This chain continued until the entire room had evacuated, and most of us will never know why. I've never seen anything else like it.