A person can beat a polygraph test by triggering strong reactions during the test questions and remaining calm as the pertinent questions come up, according to Elizabeth Flock for U.S. News & World Report. Causing pain to oneself can spark a strong emotional response when the test questions are asked, notes Natalie Wolchover for Live Science.
A person passes a polygraph test when the false questions read as stronger lies than the most important ones, reports Wolchover. For example, the interrogator asks the subject a series of control questions that are essentially trick questions to get a reading of how well the subject controls an obvious lie. The trick is to trigger less of an emotional response during the important questions to pass the test, which means the interrogated person must spark a high emotional reading during the testing phase. One method is to change vital signs by poking a thumbtack or a sharp object in a shoe. Thinking of frightening thoughts also fosters a heightened emotional state. The person being interrogated can try to solve a hard math problem to induce sweating.
Biting the tongue while lying creates a strong reaction on the polygraph needles when the test questions are asked. This raises red flags for the interviewer, setting the stage for the more pertinent questions. The person being interrogated can fantasize about such things as drinking beer or a peaceful summer night to be in a relaxed state, explains Flock. Daydreaming while lying is crucial. The test needles spike to a lesser extent when the real questions are asked, but the subject still passes the test.