Relationship or Fidelity Polygraph/Lie Detector Testing

A polygraph/lie detector test should be an investigation for the truth about a certain event or events that has already happened. Most clients that are looking for a relationship test start with the shotgun approach (multiple issues) and that can never give you a truly accurate polygraph exam. A polygraph exam has to be based on a single target or issue.
I have been administering polygraph examinations for over twenty six years and running fidelity or relationship tests for over twenty six years. I have on a weekly basis had a client walk into my office and hand me a page of questions to ask. The questions will be of mixed issue and the exam cannot be accurate because a person can only be afraid of one thing at a time. Example: if I were to place you in my office with a poisonous spider, a poisonous lizard, and a poisonous snake, you would be more afraid of one of these threats than the other two. If I left the office for fifteen minutes and then returned, you would have paid the most attention to that threat that caused you the greatest fear or concern.
The interview that should take place in a private area where only the two concerned parties are present and all questions that the person asking the other partner to take the exam should be asked at that time. From this interview the target of the test should be identified and the questions can be formulated. Several targets of fidelity testing are: sex, pornography, children (usually belonging to a couple), money, property, and many others too numerous to list. The person requesting the test at that time should select that target that is most important to them and communicate them to their therapists or the polygraph examiner.
The pre-test interview should have both parties present for the explanation of polygraph and the testing procedures. The question formulation will be done at this time and all parties will agree on the questions or an explanation of why a question cannot be asked will be explained.
The polygraph examiner should use a validated technique and have certified training in sexual testing.
If you have questions or need further explanation of these procedures, please feel free to call Bruce Stevenson at 512-719-4310.
Thanks for your time.

Bruce Stevenson


Tools of the Trade

  • Respiratory rate – Two pneumographs, rubber tubes filled with air, are placed around the test subject’s chest and abdomen. When the chest or abdominal muscles expand, the air inside the tubes is displaced. In an analog polygraph, the displaced air acts on a bellows, an accordion-like device that contracts when the tubes expand. This bellows is attached to a mechanical arm, which is connected to an ink-filled pen that makes marks on the scrolling paper when the subject takes a breath. A digital polygraph also uses the pneumographs, but employs transducers to convert the energy of the displaced air into electronic signals.
  • Blood pressure/heart rate – A blood-pressure cuff is placed around the subject’s upper arm. Tubing runs from the cuff to the polygraph. As blood pumps through the arm it makes sound; the changes in pressure caused by the sound displace the air in the tubes, which are connected to a bellows, which moves the pen. Again, in digital polygraphs, these signals are converted into electrical signals by transducers.
  • Galvanic skin resistance (GSR) – This is also called electro-dermal activity, and is basically a measure of the sweat on your fingertips. The finger tips are one of the most porous areas on the body and so are a good place to look for sweat. The idea is that we sweat more when we are placed under stress. Fingerplates, called galvanometers, are attached to two of the subject’s fingers. These plates measure the skin’s ability to conduct electricity. When the skin is hydrated (as with sweat), it conducts electricity much more easily than when it is dry.
Tools of the trade