Peer Pressure, cf. conformity
Crowd control is the method of making sure that a large crowd does not get out of hand. But the term may also refer to the control a crowd can wield over an individual. I was reminded of this in a newspaper article about an old carnival headliner nicknamed "Cannonball." In his younger days he was blasted out of a cannon 1200 times. When asked why he did this, he replied, "Do you know what it's like to feel the applause of 60,000 people? That's why I did it!"