If you'd like to see a revivalist preacher at work, there are probably several in your city. Go to the church or hall early and sit in the rear, about three-quarters of the way back. Most likely repetitive music will be played while the people come in for the service. A repetitive beat, ideally ranging from 45 to 72 beats per minute (a rhythm close to the beat of the human heart), is very hypnotic and can generate an eyes-open altered state of consciousness in a very high percentage of people. And, once you are in a relaxed "alpha" state, you are at least 25 times as suggestible as you would be in alert "beta" consciousness. The music is probably the same for every service, or incorporates the same beat, and many of the people will go into an altered state almost immediately upon entering the sanctuary. Subconsciously, they recall their state of mind from previous services and respond according to the post-hypnotic programming.