text: According to the Facial Feedback Theory of Emotions, moving your facial muscles not only can expresses emotion, but also may even help produce them. What it saying is it can also detect it a persons faking it or not, that called Empathy. So they can use it on the students to tell that if they are sorry for punching another kid or happy when they're actually not. Whoever though of making reveal the truth is thats theres so much to explore.