Do you have something on your conscience? The chances that a variograph test will detect even the slightest lie are very high. Your body’s reactions – even those you don’t know about – will betray you. How does a professional lie detector work, can it be fooled and what do the regulations say about it? We explain!
The professional lie detector and its capabilities
The polygraph, more commonly referred to as a lie detector, is a device that allows the truthfulness of the person being tested to be assessed with almost 100 per cent efficiency. This equipment has been used in the past during interrogations. Nowadays, however, it is far more frequently used for private purposes.
The polygraphic examinations usually concern:
- partnership or marital loyalty,
- the integrity of employees,
- addiction to alcohol, drugs, pornography, etc,
- verification of statements made by persons suspected of a crime,
- the possibility of clearing oneself of false accusations,
- identifying the perpetrator of a theft, murder, rape, etc,
- recruitment processes for the secret services,
- verification of witnesses.
A professional lie detector is often the only way to verify a person’s truthfulness. Of course, there is a chance of making a mistake – but it is negligible. This is especially true if the examination is carried out by specialists, under sterile conditions and using the appropriate equipment.
How much does a lie detector test cost?
Nowadays, a polygraph examination is privately available to everyone. The cost of such a procedure depends, among other things, on the subject of the check, its duration and location. Typically, you will have to pay between £1,000 and several thousand to carry out this type of operation.
How does a polygraph work?
A professional lie detector accurately analyses the behaviour of the subject’s body to the answers given. All physiological processes in the body are monitored – even those of which we are unaware. Thus, there is no possibility of consciously influencing them. This means that it is impossible to deceive the polygraph yourself.
A lie detector test analyses:
- heart rate and blood pressure,
- frequency and breathing profile,
- changes in the size of the pupil of the eye,
- electrical resistance of the skin (skin-galvanic reaction)
Despite appearances, lying is not natural for humans. It is a difficult and stressful process for the body, which has a high emotional impact. When we tell an untruth, our brain has to work at a much higher speed and needs stronger oxygenation.
When we lie, we have an interest in doing so. We are very keen that our interlocutor does not learn the truth – especially when the topic of conversation is issues, betrayal, theft or other crime.
All this causes our body to react with stress. Our blood pressure rises, we start to sweat, our breathing quickens and our heart beats faster. In addition, we become nervous – we stammer and begin to ramble in our statements. All this is visible on the polygraph’s report of physiological reactions.
How does a lie detector test work?
A dark, empty room. A table with three chairs in the middle. The investigator and the polygraph operator sit opposite the stressed suspect, who is hooked up to the apparatus . There is cigarette smoke in the air and the atmosphere in the room is far from friendly. This is probably how most of us imagine a lie detector test.
In reality, the procedure has nothing to do with scenes familiar to us from crime films. Before the actual examination can take place, the person selected for it must undergo a comprehensive medical history. This is because, in some circumstances, the results of a polygraph test could be inaccurate (e.g. in the case of antidepressant use).
Sensors measuring physiological reactions are then placed on the body of the interrogated person. These are placed on the fingertips, chest and forearm, among others.
The examination with a professional lie detector is divided into:
- neutral questions – relating to objective issues, such as the weather or what the person under scrutiny is currently seeing,
- control questions – designed to check the correct functioning of the equipment and the initial reactions of the subject, e.g. ‘what is your name?’,
- critical questions – relating to the main issue of the investigation, e.g. ‘did you steal Mr Adrian’s wallet?’.
It is worth noting that the investigator must only ask questions that can be answered unequivocally in the affirmative or negative. The interrogator should not give complex statements, as this may interfere with the subsequent analysis.
Is the lie detector reliable? Analysis of the results
Why should answers be short, to the point and focused solely on the question asked? In this way, the expert analysing the physiological reactions will be able to attribute specific processes to the explanations.
The truthfulness tester generates a report in real time in the form of a graph. Adequate knowledge and experience are needed to read it correctly. Also, the questions are constructed in such a way as to achieve the most reliable results. This is why, once you have decided on a polygraph examination, it is worth taking professional help.
Is polygraph testing legal?
Until 2015, a professional lie detector could still be used in Poland to interrogate suspects by the police. The results obtained were taken into account as evidence in the subsequent course of the investigation, which in theory carried the possibility of an erroneous verdict.
Today, the use of the polygraph is fully legal, but the device cannot be used in investigations by Polish law enforcement unless the suspect himself agrees. In that case, however, the results of the analysis cannot serve as binding evidence.
Truthfulness testing devices are currently mainly used privately. Selected companies, including, among others, the Detective Store, offer to carry out such checks on request by experienced specialists.
Professional lie detector – FAQ
Are you interested in the subject of lie detector tests? Find out the answers to the most frequently asked questions!
What is a polygraph?
A polygraph, also known as a lie detector, is a device that tests the physiological reactions of the body to answers given. Based on these, it is possible to assess whether or not the person under scrutiny is telling the truth.
How does a polygraph work?
The polygraph analyses the physiological processes of the person under scrutiny and, based on these, assesses whether his or her answers are lies. Parameters are measured using special sensors attached to various parts of the interrogator’s body.
How much does a lie detector cost?
The price of a lie detector depends, among other things, on its sophistication, the features offered and the manufacturer. The cheapest models can be purchased for around £2,000. Advanced variants, such as the Stoelting CPS Pro polygraph, cost between £5,000 and up to £20,000.
What does a polygraph examination look like?
The polygraph examination is preceded by a comprehensive medical interview. Once this is completed, the examinee is connected to special sensors that control physical processes. The investigator asks him neutral, control and critical questions – a report is generated while he answers. The whole process takes place under sterile conditions.
Is the polygraph reliable?
A professional lie detector and the proper execution of the test guarantee a success rate of approximately 95 per cent. For this reason, the results of the check cannot be considered as binding evidence in court.