Polygraph Testing FAQs
Q: What is a polygraph?
The polygraph is an instrument that records internal physiological changes. It records respiratory activity, electro dermal activity and cardio (blood volume) activity. Physiological changes occur in a person’s body when they are not truthful. These changes are recorded by the polygraph instrument; then evaluated by the polygraph examiner to determine truth or deception.
Q: How long does a polygraph examination take?
The length of a polygraph examination should be 90 minutes in duration; however each examination is unique and depends on many factors, including the complexity of the issue, what type of testing is being conducted, and the level of the examinee’s cooperation. A person scheduled for an exam should plan on at least two hours.
Q: Can everyone be tested?
Most people are suitable candidates for an examination. Physical factors that may prevent an examination include pregnancy, recent major surgery, paralysis, severe colds and respiratory problems. Juvenile subjects under the age of 14 are often difficult to examine due to a lack of maturity. On occasion, psychological problems may prevent an examination.
Q: What is the best way to prepare for a polygraph examination?
A person should get an adequate amount of sleep prior to the examination, use prescribed medication as directed and do not use alcohol or illegal drugs within 24 hours of the scheduled examination. If you have any questions, contact the examiner.
Q: Will nerves affect the outcome?
All examinees have some type of general nervous tension and may feel guilty about taking a polygraph exam. During the pretest phase, the examiner will review all elements of the examination and review the test questions prior to administering the examination. By this time, the innocent examinee will be a bit more relaxed; nervousness will not cause the innocent examinee to be shown deceptive. As long as you tell the truth to all of the test questions, then you may just be nervous during the entire test. However, if you tell a lie to any of the test questions, you may be nervous but have now told a lie causing physiological changes to occur.
Q: Can you “beat” the polygraph test?
Studies show there is nothing a person can deliberately and consciously do to cause a diagnostic error if the examiner is qualified and follows proper procedures. However, if a truthful examinee attempts to alter the data by using deliberate distortions, the examinee may be determined as engaging in deceptive behavior by the examiner. A well trained, competent examiner will be able to differentiate between truth and deception.
