The Crowd Mentality

Just something I noticed over a couple of days, watching various sporting events, that struck me as odd.

What compels us to behave in an identical fashion when in a large group?

Such as, a crowd at a UFC event isn't enjoying a fight, so they chant, "BULL SHIT." One person's urge to say this is one thing, but what about everyone nearby?

Or the wave? What on earth gets people to do the wave?


I don't know why this intrigued me, it just did.