A polygraph doesn’t detect lies: Volodymyr Vedmid on jealousy, corruption, and myths surrounding the lie detector
20 May 10:25
Interview
A polygraph is not a “lie detector,” but a complex tool that helps specialists analyze a person’s reactions. How does polygraph testing work? Is it possible to cheat a polygraph? Who undergoes these tests most often—jealous husbands or suspicious wives? And why might even a professional polygraph examiner be approached with a bribe?
Vladimir Vedmid, head of the National Association of Polygraph Examiners of Ukraine, discussed these topics in an interview for the "Komersant Ukrainian" YouTube channel.
— Mr. Volodymyr, hello!
— Good afternoon, thank you for the invitation!
— Let’s start our conversation by discussing what a polygraph is and how exactly this device works?
— A polygraph is a multi-channel device that records a person’s physiological reactions. Between 5 and 10 sensors are attached to the body, which measure breathing, cardiovascular responses, changes in skin electrical potential, tremors, and other indicators.
“For example, one of the key channels is the skin conductance response. It records an instantaneous change in skin electrical potential in response to a stimulus—that is, a question or even a photograph. The reaction occurs in literally a fraction of a second. The polygraph doesn’t detect lies. It detects the significance of the information to the person. We’re not interested in the answer itself, but in the subconscious’s instant reaction.”
— So, does a polygraph examiner analyze reactions more than words?
— Exactly. A person can say anything. Answers are often predictable. But if a strong reaction occurs to a specific question—that’s already a signal for analysis. For example, if $47,000 was stolen from the office and only the person involved knows the exact amount, then among the various options, there will be a consistent reaction specifically to the number “47.” The same applies to locations, objects, or photographs of people. We compare reactions to similar stimuli and analyze patterns.
— Who is more likely to take a polygraph test due to jealousy—men or women?
— Generally, the statistics are about 50-50. But there are nuances. Constant anxiety and jealousy are more common in women. Pathological jealousy, however, is more common in men. These are cases where a person is literally obsessed with suspicion. Sometimes there are situations where men in their 60s want to find out what happened 20–30 years ago. For example, whether their wife kissed someone by the well in her youth. Stories like that really do happen.
— Is it possible to tell if someone is lying without a polygraph?
— Sometimes yes, sometimes no. It depends on the person themselves and their level of self-control. There is a separate field—profiling or non-instrumental lie detection. This involves analyzing facial expressions, micro-gestures, nonverbal behavior, and speech. We’ve even launched separate profiling courses. Businesspeople often request this type of analysis during negotiations when it’s not possible to offer a polygraph to the other party but you need to assess their behavior.
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— Is it possible to fool a polygraph?
— It is impossible to deceive a polygraph because it is simply a tool. You can try to mislead the polygraph examiner. There are three main types of countermeasures: mechanical, pharmacological, and psychological.
Mechanical countermeasures involve attempts to move, press with fingers, bite the tongue, or induce pain. But modern chairs have sensors to detect such actions, so they are visible.
“Pharmacological countermeasures involve either sedatives or stimulants and energy drinks, which are meant to ‘clutter’ the reaction graph. But a professional polygraph examiner assesses a person’s condition even before the test begins.”
There are even people who deliberately stay awake for several days or avoid using the restroom before the test. Such things are also noticeable.
— Is there corruption among polygraph examiners?
— Of course there is. Polygraph examiners are just like judges or law enforcement officers. Some may be tempted to tamper with the results. We have uncovered cases of rigged tests and expelled such individuals from the association. We have also expelled those who taught polygraph countermeasures. Personally, I cannot be bought. My reputation is more important to me.
— How should one properly prepare for a polygraph test?
— People are less nervous when they understand the procedure. Before the test, we explain all the respondent’s rights: they can refuse to answer, stop the procedure, and the questions will not concern religion, sexual orientation, or other personal topics unless they are related to the investigation.
“The main thing is to explain to an innocent person that they won’t be ‘caught’ for all the sins of their life. If it concerns a specific theft, then the test will focus solely on that.”
— Who should not take a polygraph test?
— People with mental disorders, those who have suffered strokes or heart attacks, those experiencing acute pain, or those with cardiovascular diseases. Also, many polygraph examiners, myself included, do not test pregnant women due to potential stress. There is an official list of conditions under which polygraph testing is not conducted.
— How much does a polygraph cost, and can anyone buy one?
— Any individual can buy a polygraph. The Ukrainian “Rubicon” polygraph costs approximately 3,500–4,000 euros. American models range from 7,000 to 12,000 dollars, depending on the configuration. Polygraph examiner training courses cost about $2,000. The training lasts 5–6 weeks, after which students undergo practical training with actual subjects.
— How do you find a professional polygraph examiner?
— First and foremost, check whether the specialist is listed in the registry of the National Association of Polygraph Examiners. But the person’s overall demeanor is also important. Observe how the polygraph examiner speaks, how they articulate their thoughts, and how they prepare documents. Professionalism is evident even in the details—grammar, logic, and responsibility.
— Should polygraph testing be introduced for government officials and lawmakers?
— A systematic approach is needed. But the main question is: what exactly should be asked? If you ask about any instances of corruption throughout their entire lives, it may turn out that there are almost no “perfect” candidates. Therefore, the screening criteria must be formulated very carefully.
— How much does a polygraph test cost?
— On average, between 3,000 and 5,000 hryvnias per test.
— Can testing be conducted for several days in a row?
— A repeat test is possible if the reactions were ambiguous. But there needs to be a break of at least 3–4 days between tests. A professional polygraph examiner must not “pressure” a person into a confession. If the polygraph is used as a tool for psychological pressure, that is a violation of professional ethics.
— Who is suited for the profession of polygraph examiner?
— This job isn’t for impulsive people. A polygraph examiner must be stress-resistant, attentive, knowledgeable, and a good listener. Life experience, analytical thinking, and the ability to communicate with people at all levels—from workers to top managers and generals—are important. Sometimes you can get more information without a polygraph than with one. The key is to structure the conversation correctly.
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