Two contestants, typically a returning champion and a challenger, entered separate isolation booths and donned pairs of headphones. The arrangement of the booths and the studio lighting prevented the contestants from seeing or hearing each other or the audience. At any given moment during the game, one booth would be "open", meaning that the occupant could hear the host in the headphones and could speak using the booth's microphone. The other booth would be "closed", with its microphone disabled and the headphones playing music to prevent the contestant from hearing the game. After each question, sounds of laughter and applause were played through the headphones of the contestant in the closed booth in order to prevent the contestant from learning the outcome of the opponent's turn.