Lie Detector

Polygraph testing is often used by private investigators to determine whether someone is telling the truth. Psychological stimuli causes physiological changes in the body which will then be picked up by the polygraph. When someone senses danger, the body’s nervous system will send the body into a fight, flight or freeze state. This occurs naturally and cannot be controlled no matter how hard one tries. This state will cause the body to undergo changes which can be measured by the polygraph. A polygraph examination can take up to 3 hours and includes four different segments including the pre-test interview, collection of charts, analysis and the post-test interview.

Pre-Test Interview

The examiner will explain how the test will work during the pre-test interview. He will also discuss the issue they are trying to investigate and develop the questions to be asked during the examination. This is a crucial component of the entire process and can take the longest to complete. The examinee will have to decide whether they want to lie or to tell the truth.

Pneumographs that can measure respiratory function will be attached to the examinee’s abdomen and chest. On the examinee’s upper arm, a blood-pressure cuff will be attached to it. Galvanometers, which are essentially fingerplates, will also be attached to two of the examinee’s fingers. These finger plates determine how well the skin conduct electricity. When the skin is sweaty, it will conduct electricity more easily.

The information collected from the pneumograph, blood-pressure cuff and galvanometers will be recorded on a computer screen and charted for professionals to analyze.

Chart Collection

Question sets developed during the pre-test interview will be asked during this phase. The examinee will be asked the questions 2-4 times with a 20-45 second interval in between in order to record a precise reading.

Chart Analysis

Once the information has been collected and charted, the examiners will analyze what they see on the polygrams. The polygram will be reviewed by more than one person to ensure quality control. After a stringent evaluation and review process, the examiners will reach a final decision.

Post-test Interview

Test results will be given to the examinee during the post-test interview. This is also a chance for both the examiner and examinee to clarify any questions they may have. The examinee may also be given the opportunity to explain their perspective on the final result.

Final Report

In the final report, both the results and the findings of the polygraph examination will be recorded. This includes the questions asked during the examination as well as the professional opinion of the polygraph examiner. A polygraph examiner may come to the following conclusions:

  • Inconclusive: Not enough data was gathered to judge the examinee.
  • Deception Indicated: Examinee was untruthful in his responses to the questions asked.
  • No Deception Indicated: Examinee was telling the truth in his responses to the questions asked.

Polygraph testing is often used to assist investigations to determine whether someone is telling the truth. If you wish to schedule a polygraph testing to figure out the truth, Probity Investigations can help you find a polygraph examiner near you to help you. Polygraph examiners in our network are reliable and efficient, and can get you the results of the examination quickly. Visit us and schedule a polygraph examiner today.