text: The machine uses the muscles in your face to detect emotions. This is useful because different muscles makes different emotions, In the article the athour explained how the machine can tell if someone was happy or not. "To an expert, faces don't lie; these muscle clues are sometimes used to spot when a "smiling" politician or celebrity isn't being truthful." That explains that even if the person tries to change their emotion the real one will still be seen because of the muscles that they are using.