Q&A With Ken Donaldson, The Lie Detective

  1. How did you get into lie detector testing?
  2. I attended the Academy of Polygraph Science in Largo, Florida. I am an accredited forensic psychophysiologist. This means I study how the mind (psycho) affects the body (physio). I am certified through the American Polygraph Association.

  3. What kind of equipment do you use to do a polygraph exam?
  4. I use the Lafayette LX 4000 computerized polygraph equipment. I have components that I put on my examinee. The components consist of two pneumo tubes that I put around a person’s body to measure their breathing, two pads that I put on their fingers to measure their galvanic skin response, or how much they’re perspiring, and I have a blood pressure cuff that I put on their arm and monitor their pulse rate and their blood volume. All those components are hooked into a central hub called a DAS (data acquisition system), which converts the electronic data into a digital signal that the computer can analyze.

  5. What are the most common issues that you test for?
  6. I do a lot of testing for fidelity – where one partner in a couple suspects the other of being unfaithful. I also deal with family issues such as suspected drug use, gambling or problems with teenagers.

    As well I do corporate polygraphs for businesses wanting to do pre–employment screening, and periodic screening of employees for theft or fraud.

  7. Who can take a polygraph examination?
  8. Anyone who is seeking the truth and wants closure to an issue.

  9. Do you perform a polygraph test on anyone who wants it?
  10. Sometimes I choose to delay an examination for physiological reasons. I want my examinees to be healthy, well rested, sufficiently fed, and free of drugs or alcohol.

    If I am not sure of a client’s mental stability I may ask to speak with her health care provider before proceeding. People who are not able to tell the difference between right and wrong are not eligible for a polygraph exam because they won’t display appropriate fear responses to being caught in a lie the way most of us do.

  11. Can an employer ask an employee to take a polygraph examination?
  12. An employer can request in writing for a potential employee to voluntarily take a polygraph for statement verification or if the employer has suffered economic loss and the employee is suspected of theft.

  13. How do you decide which questions to ask on the exam?
  14. During the pre-polygraph interview phase of the examination process I spend time getting to know my examinee and other people accompanying him or her, as well as the issue of concern. I usually spend upwards of an hour or two determining what the relevant questions will be.

    In a typical exam I ask three types of questions: Irrelevant, Control, and Relevant.

    Irrelevant questions I ask right at the beginning of the sequence. I might ask the examinee, “Is this the month of May?” if it is May. I also ask the client if they intend to be truthful with me about the issue at hand. This allows the examinee to get used to the questioning and gives me a baseline reading of their physiological response to benign questions.

    A control question parallels the issue that I’m testing for, but is separated by time and place from that issue.

    A relevant question concerns the issue I am testing for. For example, did you take the money? In a test where you have multiple relevant questions, and it was a theft issue, I might ask: Did you take the money? Did you help plan or participate with anybody to take the money? Do you know who did take the money?

  15. How many times do you ask each question?
  16. For the polygraph exam I compile a list of ten questions, three of which are relevant to the issue at hand. I ask this list of questions three or four times because I need consistent data over a period of time. I need to see a notable reaction to the same question repeatedly for me to determine that the reaction wasn’t merely a coincidence.

  17. Why can you only ask questions about one topic on a polygraph exam?
  18. I conduct specific issue polygraph tests. When you do polygraph testing and try to mix issues up your accuracy goes down. If an examinee shows a physiological reaction (increased sweating or heart rate, for example) and it happens timely with them answering a question about a very specific event, it’ll tell me whether they’re being honest or deceptive.

  19. What is a Numbers Test?
  20. Before I start the specific issue testing I have the examinee do a test that I call the numbers test. I ask them to directly lie to me about a number on a piece of paper. It’s a very simple test and it goes like this: I give them a piece of paper and I tell them to pick one of these three numbers – four, five, or six. I hook them up to the polygraph instrument. I tell them to put that piece of paper under their leg and I tell them during this test to answer no to every question. The questions are as follows: regarding that piece of paper under your leg, did you write the number one? They’ll answer no. Twenty-five seconds later I’ll say did you write the number two? They say no. I progress up numerically through to the number seven. So I know that they’re telling me the truth about six questions and lying to me about one.

    This test does a couple things for me. It lets the examinee get used to having the apparatus on their body, the pacing of the questions, and it lets me look at their breathing patterns when they’re telling me the truth and when they’re being deceptive.

  21. How Accurate is a polygraph examination?
  22. A single issue polygraph examination, performed by a qualified examiner is 95–98 percent accurate.

  23. Is the polygraph admissible in court?
  24. Yes, usually polygraph evidence is used in pre-trial negotiations and plea bargain agreements.

  25. What type of lawyer would suggest that their client take a polygraph?
  26. The concept is the same for all lawyers – the polygraph examination detects deception. A lawyer could suggest that their client voluntarily take a polygraph for statement verification. Lawyers want and need to know that their client is telling the truth.

  27. How do you know when someone is lying?
  28. People are afraid of getting caught in their lie, so it’s a fear response that I’m looking for. When someone is being deceptive I can see a reaction in one or more of their physiological responses. Breathing patterns will change, the heart beats faster, blood rushes from their extremities, perspiration increases, digestion stops, and salivation stops. These are things that just happen instantly that we can’t control.

  29. Will it affect the test result if the examinee is really nervous?
  30. No. If the examinee is nervous, they will be nervous throughout the test, so I will see consistent evidence of that nervousness. During the test I look for changes to a person’s physiology (heart rate, perspiration, breathing patterns) in response to the questions I ask.

  31. Can I beat the polygraph examination?
  32. Polygraph has a very high accuracy rate of 95–98 percent. A qualified examiner is trained to pick up techniques that an examinee may use in order to try and "fool" the instrument. People who are psychotic "honestly" believe the lies they tell are the truth, therefore these people are not suited for a polygraph examination. A polygraph examination can detect deception.

  33. Do you have tricks to catch people in a lie?
  34. No. There are no surprise questions on my polygraph exams. I ensure that the examinee is completely comfortable with the exact wording and order of the questions I will be asking them. I walk them through the entire examination process before ever hooking them up to the polygraph device.

  35. Can the examinee bring a family member or friend to the polygraph exam?
  36. Clients are welcome to bring someone to the pre-test interview. In the case of fidelity issues I encourage both parties to attend the polygraph process to help me design the relevant questions for the examination. However, during the exam I isolate the examinee and seat him so he is facing a blank wall. The fewer distractions, the more easily the examinee will focus on the questions, and the more accurate my results will be.

  37. Can I train myself to beat the polygraph test?
  38. No. It’s a person’s own physiological response to the questions that write the chart. It’s fear of being caught in their lie. It’s a fear response I’m looking for.

    People who are psychotic don’t really care if they pass or fail the test, and don’t have an innate sense of right and wrong, so they wouldn’t be good candidates to take a polygraph test in the first place.

  39. How much does a polygraph examination cost?
  40. Single issue polygraph examination: $450 Contract fees are negotiated.(some additional fees and deposits may apply)

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