There’s a dynamic relationship between live performers and the audience. Just as dancers, actors and musicians amuse, provoke or otherwise move their public, the public moves them. Muttering in the seats can be heard onstage. So can the odd argument and ringtones. The sounds and behaviors of spectators can affect dancers’ psychology and even performance quality. They’re energized by cheers, of course, and demoralized when they’re expecting applause or laughter and there’s only silence. But they pick up on far more.