Debunking Myths & Misconceptions About Polygraph Exams

Polygraph exams, often referred to as lie detectors, have always been a fascination. A large part of that comes from how they have been portrayed in movies and television. However, this has resulted in a lot of misconceptions about what polygraph examinations in Knoxville, TN, really look like. Let’s take a look at some of the popular myths and misconceptions and uncover the truth about polygraphs!

What is a Polygraph Examination?

Although polygraphs are often referred to as a lie detector, that isn’t really an accurate description of what the test does. The machine is designed to measure a number of different physiological changes in the subject’s body including blood pressure, heart rate and respiration rate. These are the changes that are often an indication of stress or anxiety, both of which are associated with lying because it can trigger a flight or fight response in the body. When a person is being deceitful, it is normal for their heart rate to increase and their breathing patterns may become irregular. On the other hand, when someone is telling the truth these physiological readings will remain stable. When taking polygraph examinations in Knoxville, TN, the polygraph machine takes these readings and the examiner then interprets the results.

Myth 1 - Polygraph is Always 100% Accurate

There is a common misconception that polygraph examinations in Knoxville, TN, are always completely infallible. In reality this is not the case. While there is a high rate of accuracy, up to 98%, but there are some factors that can impact the results. One of the main contributing factors is the skill and expertise of the examiner administering the test. It takes a great deal of time to develop a high quality questioning technique and a great deal of skill to read the physiological responses. Your test can only ever be as accurate as your examiner. If you are looking for polygraph examinations in Knoxville, TN, you will struggle to find anyone with more experience than Kendall Investigations. All polygraphs are administered by Kendall Shull, a former chief of the FBI Polygraph Program in Washington DC. He is the only person in the world to have attained a Master’s Degree in Polygraph and has published a variety of research on the subject. Kendall Investigations is also the only polygraph examiner to maintain a permanent office here in Knoxville, TN.

Myth 2 - Polygraph Reads Your Thoughts!

Another big myth about polygraph examinations in Knoxville, TN, is that the machine has the ability to access your hidden thoughts and secrets! Television probably has a big role to play in this particular misconception, although part of it may also come from a lack of understanding of how the test actually works! As described above, the polygraph equipment is tracking physiological changes, not thoughts or brainwaves! The examiner will pose specific questions agreed upon in advance and monitor the subject’s responses to those questions. Only that particular area of deception will be questioned, for example whether or not someone has had sexual contact with another person who is not their partner. The test won’t reveal truths about other topics that have not been included in the questions, unless the subject decides to reveal them. This is why it is important to think carefully about the most appropriate questions to ask during the test.

Myth 3 - It’s Easy to Beat a Polygraph

When conducting polygraph examinations in Knoxville, TN, we come across a large number of people are are confident that they can beat a polygraph by manipulating the results. However, this is certainly not as easy as many people believe! Experience polygraph examiners like Kendall Investigations are trained to recognize signs that a subject is attempting to cheat the machine by controlling their breathing or attempting to alter their physiological responses. They have techniques and tricks at their disposal to catch out people attempting to manipulate their results. The equipment itself is also designed to detect and measure countermeasures making it incredibly difficult to cheat.

Myth 4 - All Polygraph Examiners Are The Same

Another misconception we have seen is that it doesn’t matter which polygrapher examiner you work with as they are all the same. This is not true. The skill and the experience of your polygraph examiner is going to have a huge impact on the accuracy and reliability of the test. Someone with just a few weeks experience will not be able to offer the same quality of test as someone who has been in the industry for decades! As discussed above, Kendall Investigations’ founder Kendall Shull is one of the most highly qualified polygraph examiners in Knoxville, TN, and the rest of the country. He has developed his examinations techniques and gained a wealth of experience both during his time as an FBI Special Agent and in his civilian practice. If you want the most accurate results from your polygraph it is important to choose polygraph examiners in Knoville, TN, with a proven track record and experience.

Uncover the truth!


Ken Shull served as a Special Agent with the FBI for almost 25 years and was head of the FBI Polygraph program until his retirement in 2001. At that time he set up the Kendall Investigations practice as a private investigator in Knoxville, TN offering Polygraph services, private investigations, and security guards. Ken is a member of the American Polygraph Association and The American Association of Police Polygraphists.

The Truth is Still the Truth Even if No One Believes it, A Lie is Still a Lie Even if Everyone Believes it.