William Castle, for instance, was a master promoter. In one scheme involving The Tingler, Vincent Price warns in the movie that "the only way to stop the monster is to scream. That's the signal to the projectionist to throw the switch. Under ten or twelve seats were some electric motors, war surplus things that Castle got a bargain on. The motors vibrated the seat, in the hope of scaring a scream out of someone. Just in case it didn't Castle...