Even willfully "random" crowd behavior is predictable.

Ted Van Pelt/Flickr

Stop me if you've heard this one. A Cornell graduate physics student takes his girlfriend to her first heavy metal concert. Instead of diving straight into the mosh pit, as he typically would, he hangs back "to keep an eye on her."

Being a physicist first and a mosher second ("fieldwork was independently funded"), the student, Jesse Silverberg, can't help but notice curious patterns in what had always felt like the epitome of chaos. "Being on the outside for the first time, I was absolutely amazed at what I saw -- there were all sorts of collective behaviors emerging that I never would have noticed from the inside." So for an even better perspective, he turns to YouTube, to figure out what happens to people under the "extreme conditions" borne of a combination of "loud, fast music (130 dB, 350 beats per minute) ... bright, flashing lights, and frequent intoxication."

What he found, of course, was the "collective phenomenon consisting of 10^1 to 10^2 participants commonly referred to as a mosh pit." And he was able to prove his initial observation: While the individual movements of moshers may be random, their collective behavior follows a few simple rules.

He and his team then "simplif[ied] the complex behavioral dynamics of each human mosher to that of a simple soft-bodied particle," creating an interactive model for demonstrating their movement that, even if you're not clear on the physics, is fun to play with (try turning up the noise strength and watch what happens).