The introduction of the polygraph in the 1920s changed the way law enforcement dealt with questioning suspects involved in crimes. Before the polygraph, there was no way to discern if a person was lying or telling the truth.

Criminals are excellent liars, and figuring out if they’re being deceptive in interrogations is very challenging, even for the best detectives. The introduction of the lie detector gave law enforcement an edge over deception. For the first time in history, there was a scientific method for uncovering a person’s intentions and answers in interrogations.

The first designs of the polygraph dramatically changed the interrogation landscape for law enforcement. Conviction rates soared to new heights in the next 100 years, all because of a device that could help uncover the truth.

However, the device was not solely responsible for the success of polygraph exams in uncovering deception. The examiner conducting the lie detector test was as important to the development of the technology and its success in the field.

Advancing the methodology around asking questions in polygraph exams also enhanced the efficacy of the process in uncovering deception. In this post, we’ll look at the four primary questioning techniques used by examiners in polygraph exams.


Keeler & Reid – The Origin of the Polygraph Questioning Technique

Polygraph exams have changed a lot over the last century since John Larson invented the first lie detector device. Innovators like Leonard Keeler made considerable advances in the efficacy and effectiveness of polygraph machines and questioning techniques.

However, it was John E. Reid who advanced the questioning methodology for polygraph exams. Reid was a former Chicago police officer, psychologist, and polygraph expert following on from the work of Leonard Keeler in the 1950s.

Reid developed the “Reid Technique” in the 1950s. His method involved creating a high-pressure environment for the polygraph examinee. When the examinee was on edge and ready to confess, Reid would follow up with sympathy and understanding to coax a confession out of the suspect.

There was significant controversy attached to the Reid Technique, with proponents of the methodology praising its effectiveness, while detractors said it brought about a high percentage of false confessions. In 1955, Reid used the technique to gain an admission of guilt from Darrel Parker, the prime suspect in the murder of Parker’s wife.

Reid got the confession from Parker, where he admitted to murdering his wife but recanted his statement the following day. However, the confession was admitted to evidence in his trial, where the jury convicted him, and a judge sentenced him to life imprisonment.

The success of this case shot Reid to stardom, and his technique became the gold standard in polygraph questioning. However, it would turn out Parker was innocent and wrongfully accused. As a result, he sued the state for compensation of $500,000.

Reid formed his company, “John E. Reid and Associates,” and passed away in 1982. However, his company continued to advance the field of polygraph questioning techniques, 

founding “The Reid Institute” in Chicago in 1999.

The Reid Technique involves nine steps in the method.

  1. Positive confrontation. Tell the interviewee the police identify them as the prime suspect in the case. Offer them the opportunity to explain their story.
  2. Attempt to shift blame from the suspect to another party or circumstance that caused the suspect to commit the crime.
  3. Attempt to minimize the frequency of denial by the suspect.
  4. Attempt to move towards the suspect’s acknowledgment of the crime when they attempt to explain why they did not do it.
  5. Reinforce your sincerity, attempting to ensure that the suspect remains receptive.
  6. When the suspect becomes quiet and starts to listen, offer alternatives. If the suspect breaks down and cries, infer guilt on them.
  7. Pose an “alternative question.” Provide two scenarios for what occurred. The suspect must choose one or the other, but either way, they admit guilt.
  8. Lead the suspect to repeat their admission of guilt in front of a witness. Develop corroborating evidence to establish the validity of the suspect’s confession.
  9. Document the admission of guilt and/or confession via a recorded statement (video, audio, or written).

There is plenty of controversy around the Reid Technique and its use in interrogations. It’s no longer used in most criminal polygraph scenarios. However, the FBI did admit to using it in their standard practices for polygraph interrogation in 2013.

The Reid Technique is banned in many countries around the world for use in law enforcement polygraph exams. For instance, Germany doesn’t allow its use. The Reid Technique is forbidden for use in polygraph exams in the private sector and in most public sector institutions.

Instead, polygraph examiners rely on one of the four techniques when interviewing employees in pre-employment screening or employee polygraph examinations.


What are the Types of Questioning Techniques Used in Polygraph Exams?

While the methodology used in polygraph exams has changed, the physiological responses measured in polygraph exams remain the same. Examiners monitor an examinee’s pulse and respiration rate, blood pressure, sweat gland activity, and movement during the exam.

Examiners will typically use one of the following four techniques when assessing a person in a polygraph exam. They’ll choose the questioning technique based on the situation and their training.


The QCT – Control Question Technique

The “Control Question technique,” otherwise known as the “Comparison Question Test,” is the most common questioning methodology used in polygraph examinations. The system utilizes two types of questions. The examiner asks relevant questions about the situation, but they also ask “control questions,” which indirectly relate to the incident in question.

So, if an employee is questioned about their involvement in a $5,000 theft at their company, the examiner might use the following questioning format.

  • Have you ever stolen something?
  • Have you ever stolen money from an employer?
  • Did you steal $5,000 from your employer?

The subject will not want to admit to stealing anything. However, the reality is most people had stolen something in their lifetime, whether it was a dollar from their mom’s purse as a teenager, a candy bar from the corner store when they were a kid, or a newspaper from the newsagent as an adult.

However, most people will deny this behavior under a polygraph exam because they think it will make them look guilty of committing the $5,000 theft, even if they didn’t do it. The innocent person will react more strongly to the control questions, which they’re lying about than they will to the third and most relevant question, which they’re answering truthfully.

A guilty suspect shows a stronger reaction to the relevant question, despite lying on both the control and relevant questions. The relevant question provokes a stronger response because it immediately threatens the suspect.


The RIT – Relevant or Irrelevant Questioning Technique

The RIT is the most established questioning method for polygraph exams. The RIT involves the examiner asking irrelevant and relevant questions about the $5,000 theft. Relevant questions pertain specifically to the theft in question, which the suspect is under examination for potentially committing. The line of questioning for the RIT might appear as follows.

  • Is your name John Malcolm?
  • Are you 43?
  • Do you live at 411 Snitch Street?
  • Did you steal $5,000 from your employer?

The initial three questions in the series are irrelevant, but they provide the examiner with a baseline indicating when the subject is telling the truth. They don’t prompt the fight-or-flight response in the subject that indicates deception.

However, when asked about stealing $5,000 from his employer, the subject will produce a different physiological response if they’re guilty of the crime. The question initiates the fight-or-flight response by the sympathetic nervous system as they lie, and the examiner picks up these physiological changes on the polygraph software.

It shows a stark difference in responses between the initial irrelevant questions and the relevant question. If John was innocent and not lying, his physiological response should not change when asked the relevant question.


The DLT – Directed Lie Test

The Directed Lie Test (DLT) is one of the lessor-used methodologies for polygraph testing. With this method, the examiner instructs the subject to lie in response to a control question. The examiner also tells the subject to think about other instances when they were guilty of doing something they denied.

The questions cover an intentionally long period – in most cases, the subject’s lifetime – because there is a strong possibility they have done what they are being told to deny at some stage in their lives. So, the examiner might ask the control question, “Have you ever stolen anything?”

After answering, the examiner will modify the question to “Have you ever stolen anything during your lifetime?” Since the examiner already told the examinee to think about their answer to the question beforehand, any previous activity involving theft will come to the forefront of their conscious mind and show in the polygraph reading.

The physiological response will be lower in individuals telling the truth. However, guilty subjects react more strongly to relevant questions than control ones, even though they’re lying. The reason for this behavior is the threat posed by the relevant question.


The GKT – Guilty Knowledge Test

The GKT is the fourth and final polygraph questioning method and has a different process from the others. The examiner asks a multiple choice question instead of direct questions. Let’s assume the examiner is investigating whether Simon murdered his brother, Matthew, by drowning him in a lake.

In the Guilty Knowledge Test, we assume there is no way Simon could know about the method of murder used to kill Matthew. The examiner would structure the questions as follows.

  • Was Matthew strangled?
  • Was Matthew stabbed to death?
  • Was Matthew drowned?
  • Was Matthew shot to death?

Simon will deny murdering his brother, but the examiner records and assesses Simons’ responses to each type of murder method asked in the questioning process. When the examiner asks, “Was Matthew drowned?” it produces a different physiological response to the other three, indicating Simon knows the method of murder, proving his guilt.


Single vs. Multi-Issue Polygraph Questioning

Single versus multi-issue polygraph questioning doesn’t define a specific methodology of testing. Instead, it can apply to any of the techniques mentioned earlier. It’s more of a variation on a questioning theme but a crucial factor in its success, which is why it’s worth mentioning.

In multi-issue testing, the examiner asks questions relating to several issues in a single questioning session. However, results show this technique might not provide effective or accurate results. By introducing several issues into the same questioning session, they muddy the water, making it easier for the subject to avoid the fight-or-flight response and beat the polygraph exam.

Without getting into the technical aspects of the process, results of multi-issue polygraph questioning exams are more open to interpretation and unreliable. With the Single-Issue Test, the examiner only asks the subject questions relating to a single issue.

As a result, the test and the answers are concise and clear, providing accurate and dependable results. Most polygraph examiners will only use the single-issue methodology in their exams.  


Which Is the Most Effective Polygraph Questioning Technique?

The success of the methodologies in polygraph questioning depends on several factors. For instance, it could come down to the examiner’s preferred process or the nature of the misdemeanor or crime. So, the methodology of the exam is less important than the competency and experience of the polygraph examiner.

While the polygraph device and software read the subject’s physiological responses, the real talent in the process comes down to the examiner, their training, and their experience. Going back to John Reid, the man was the most revered and successful polygraph examiner due to his expertise.

A qualified, competent, and experienced examiner can ask the right questions and interpret the subject’s responses in a manner that removes any chance or error from the process. While some claim they can beat the polygraph, it’s usually the case because they have an inexperienced examiner taking the test.

These same individuals might have a very different experience if they come across an experienced examiner with tens of thousands of interviews on their resumes.

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