"A polygraph is not an interrogation, but a tool": how does a lie detector work in Lutsk and can it be fooled?
- Юридичний Факультет
- 4 hours ago
- 3 min read
Exclusive report from https://suspilne.media/lutsk/
"A lie can be easily seen in a person's eyes," psychologists say. However, according to polygraph examiner Vadym Hrachuk from Volyn, the most accurate way to detect insincerity is not facial expressions or gestures, but a special device - a polygraph.
How a lie detector works, who can take the test, and whether it can really be fooled — polygraphist Vadym Hrachuk told Sospilny.
What does a polygraph measure
A polygraph is an instrumental method of detecting insincerity that records the body's psychophysiological reactions when answering questions.
Emotional tension, in simple words, is stress. It occurs at the moment when a person decides to tell a lie," explains Vadym Grachuk.
According to him, the device records four groups of indicators:
breathing (thoracic and abdominal);
cardiovascular reactions (blood pressure, pulse, vasodilation);
motor activity (using tremor sensors);
galvanic skin response - changes in skin conductivity due to sweating.
Even if a person thinks that their palms are dry, during stress the amount of sweat increases - and the device records these changes.
From what age can you take the test
The general rule is from 18 years of age. In rare cases, in particular during criminal investigations, minors from 14 years of age are tested.
At the same time, there are categories of people who are not recommended to take a polygraph:
people with acute heart diseases;
persons with serious mental disorders (for example, epilepsy);
pregnant women;
minors due to incomplete formation of the nervous system.
The result can also be affected by temperature, acute respiratory viral infections, fatigue or taking medications.
Is there an error
According to the polygraph examiner, the device itself has no error if it is technically sound and certified.
"A polygraph is a tool. It shows what your body gives off. Error is possible only at the stage of interpreting the results and depends on the professionalism of the specialist," says Vadym Grachuk.
Can you cheat a polygraph
It is impossible to cheat the device itself, the polygraph examiner is convinced. At the same time, people sometimes try to counteract the procedure - they move, change their breathing, or come in a state of alcoholic or drug intoxication.
"If a person consciously tries to counteract, this is recorded separately in the conclusion," he notes.
According to him, even taking sedatives does not guarantee "blocking" reactions, because everyone's nervous system reacts differently.
What are control questions
Control questions are used during testing - they do not directly relate to the topic of the test, but are emotionally significant for the person. The reaction to them is compared with the reaction to the main questions.
For example, if the testing concerns the disclosure of confidential information, the control question may be about an act in childhood that causes shame. This helps determine which reaction is stronger.
Where in Ukraine is a polygraph used
Before the full-scale invasion, the polygraph was most often used in the private and public sectors — in particular, during employment.
Results of a physiological study during a polygraph. Lesya Ukrainka University
After 2022, the scope of use has expanded. According to Vadym Grachuk, the polygraph is used:
at defense enterprises;
in the military;
during checks of persons who were under occupation;
in business;
in family disputes.
The profession of a polygraph examiner is also included in the state register of professions.
Advice for those who are taking a polygraph for the first time
The polygraph examiner advises not to worry and remember that this is not an interrogation, but a voluntary procedure, more like an interview.
Polygraph examiner Vadym Grachuk. Social Lutsk
Among the recommendations:
do not drink coffee and stimulants before testing;
do not try to find ways to cheat the polygraph;
check the qualifications of the specialist;
be sincere in your answers.
"The truth always becomes known sooner or later," concludes Vadym Hrachuk.
Authors: Iryna Romanenko and Petro Yurovchyk
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