Social Contagion - It's in the Air.

"There's something out there. It's in the air. This is, this is social contagion," he says. "It will spread through a community." The term goes back to bolemia, when female sufferers threw up their food after they ate it and got really sick; now we're seeing more cases of cut-throat girls cutting themselves. School shootings with four or more deaths spread like a contagion: Each shooting tens to spark more shootings.