Ralph Barbieri administers lie detector tests to guests, who most often are suspected of cheating on their mates. Some guests admit to cheating, refuse to answer one or more of Barbieri's questions or stop the test entirely and confess on video. During the show, Maury reveals the results of the lie detector tests. Barbieri occasionally appears on the show to explain the results, often saying a person had "significant reactions" to one or more questions.