• What's between truth and lies?
  • Polygraph
  • The effect of excitement on polygraph test findings
  • Can the polygraph tester be fooled?
  • Benefits of PolygWeb test

Truth and lies

Truth and falsehood are part of the areas of research in philosophical logic and theory of knowledge (epistemology). Sentences, phrases, arguments, determinations, ideas, beliefs and the like may have a truth value (and then they are referred to as "truth-bearing", "having a truth value", or "true") or a falsehood value ("having a falsehood value" or "false").

There are a number of theories about truth and falsehood which were developed by philosophers and logicians. These include:
  • The theory of choice claims that truth is self-evident and requires no other evidence.
  • The correspondence theory of truth holds that truth corresponds to objective reality. Accordingly, an argument is true only to the degree that it expresses the state of affairs in the world.
  • The coherence theory considers truth to be anything which is consistent with (that is, derived from) any set of arguments. Generally speaking, the set of arguments is one which describes the true world in the best and most complete possible manner, in the opinion of those who choose it.
  • The consensus theory views truth as consisting only of things which a group of experts on the subject have agreed to be true.
  • Pragmatism sees "truth" as the success of the practical consequences of an idea.

Each of these theories may be interpreted as a definition of the basic nature of truth (and accordingly also of falsehood), or as a criterion for determining the truth value of arguments and sentences


A polygraph (commonly known as a "lie detector") is an instrument which is intended to pick up a person's involuntary responses in order to determine whether he is lying. Another name which is sometimes used for the device is a "truth machine". The polygraph is primarily used in criminal investigation, but can also be used in job placement and security.

The name "polygraph" is of Greek origin and signifies "many" (poly) "records" (graph). The machine was invented in the 1920s in the United States for the purpose of detecting truth and falsehood. The polygraph is based on the assumption that, when a person lies, uncontrollable physiological changes take place in his body, such as: a rise in blood pressure, a change in pulse rate and a change in the electrical conductivity of the skin.

Did you know?

One out of every five persons taking a polygraph test will be found to have lied even though he told the truth. POLYGWEB will enable you to decide whether you should take the test and what your chances of passing it are!

Principles of operation – general

The most common method of diagnosis through the use of a polygraph involves the use of comparative questions of the "probable lie" type. The polygraph subject is shown questions of two categories: relevant questions and comparison questions. Irrelevant questions, which the tester entirely ignores when calculating the results, are also written into the test.

Relevant questions

Relevant questions are direct questions on the subject of the investigation. Examples of relevant questions in a case involving a leak of confidential material from a workplace might be: "Did you transfer confidential information, which belongs to your employer, to entities which are not authorized to receive it?" or: "Did you try to obtain confidential information beyond the scope of your job requirements?", and so forth. It is important for essential questions to be phrased fairly and pertinently. In the above case, for example, it is preferable to refrain from questions such as: "Were you in any contact with entities which compete with your workplace?"

The subject must receive a list of the relevant questions in advance and must go over them at least once without being connected to the polygraph instrument. This is meant to reduce, as far as possible, the body's natural stress responses to the fact that the subject is encountering a question which may cost him his job, whether or not he was actually responsible for the leak.

Comparison questions

Comparison questions are intended to create a response of guilt feelings in the subject, irrespective of the issue for which he is about to be examined. The questions will be designed to arouse discomfort in any adult, because we are all human. In order to increase the level of reliability of the stress, some polygraph investigators emphasize to the subject the importance of telling the absolute truth, without even the slightest deviation. Some typical control questions are: "Have you ever lied?", "Describe all the times you took something, even a pen, that wasn't yours", and so forth.

Irrelevant questions

These questions are focused on known things, about which there is no reason to lie. These may include the subject's name, address, number of children and so forth. At times, the subject is asked to lie deliberately when answering some of these questions. The purpose of these questions is to increase the subject's trust in the process, and thereby to increase his response to the control questions and the relevant questions. Whether or not the subject is asked to lie when answering the irrelevant questions, they are not taken into account in analyzing the results and are not weighted in examining the consequences of the investigation.

The effect of excitement on polygraph test findings

The author of the article is an experienced tester who has performed tens of thousands of tests in more than 30 years.

The question "How great is the effect of excitement in the course of a polygraph test?" Is frequently asked.
Candidates who are slated to take a polygraph test are afraid that, although they are telling the truth, they will be diagnosed as lying only because they are very excitable.

Employers, attorneys, human resource managers and even judges also debate whether to use a polygraph as a diagnostic tool for truth and falsehood, fearing that a subject who is telling the truth will be found to have lied, merely because of excitement caused by the very occasion, and not because what he is saying is false.

Please be aware of the following:
Excitement during a polygraph test is well-known, structured, automatic behavior and cannot affect the findings of the test. Even if a truth-telling subject is extremely excited during the polygraph test, he will be diagnosed as telling the truth.
For your information: the polygraph instrument simultaneously receives and records the behavior is one of several physiological systems, which operate in an autonomous (independent and uncontrolled) manner within the body. At the beginning of the subject's physiology record, his psychophysiological state – in other words, his (emotional and physiological) stress level – is determined automatically; this state is used as a basis for comparison throughout the test.

This gives rise to two simple rules which must be internalized and applied:

  • If a subject answers a question which is put to him truthfully, does not lie, does not conceal and is not afraid of the truth, the physiological responses received and recorded by the polygraph instrument from the systems under examination will be in the range of his normal state during the test.
  • If a subject lies in answer to a question, is afraid of the truth coming out, or is afraid of sanctions against him was the truth is exposed, the physiological responses received and recorded by the polygraph instrument from the systems under examination will be significantly outside the normal range for that subject at the time of the test. These abnormal responses happen voluntarily; they result from the automatic activation of a defense mechanism which each and everyone of us has.

Accordingly, it may be said in summary that excitement before and during a polygraph test is an entirely natural behavior and is not supposed to distort the test results.

The more experienced and skilled the polygraph tester, the better he will be able to explain that set forth above to the subject, before the test begins. A professional tester knows how to use various professional techniques in order to neutralize any fears which may arise, and even to demonstrate the way the system works before the test itself is performed.

Can the Polygraph tester be fooled?

Generally speaking, it is not possible to "cheat" on a polygraph test or to distort (generally false) findings – but there can be exceptions.

A well-known basic assumption which underlies polygraph testing is that, when an ordinary person is afraid of the truth and is "forced" to lie, a number of involuntary physiological changes take place in his body, as a result of the operation of the sympathetic nervous system, which the subject cannot control (defense mechanisms).

The systems which are measured during the polygraph test our blood pressure, pulse, changes in chest cavity volumes, and electrical resistance of the skin.

The various testing techniques, especially the modern ones, are based on comparison of the strength, type and nature of the responses received from the subject while answering the various types of questions which he is asked during the polygraph test.

Theoretically speaking, if a subject is familiar with the various testing techniques, knows and understands in advance the method by which he will be examined and how the tester will determine the results of the test, knows and is capable of performing / creating artificial physiological changes at the "right" times and places without the tester noticing that these behaviors responses are not natural, he may succeed in distorting the findings.

At the same time, it should be noted that polygraph testers today take such artificial behaviors into account – whether through the use of special instrumentation or by observing the subject during the test.

The argument that some subjects can directly influence their own sympathetic and parasympathetic nervous systems and change the measured parameters as they wish is unsupported by evidence and unsubstantiated.

Benefits of PolygWeb test

PolygWeb test can be described as the preface of the polygraph test, on which it depends whether the polygraph test will be executed or not. Actually PolygWeb test is an online test that helps the people to decide whether they should go for polygraph test or not by depicting the result. It means it depicts if someone can pass the polygraph test or not. In the starting, users will be tested for their trustworthiness level by asking them various questions. The PolygWeb test simulates the polygraph test and include special algorithms for that which make the curious people to have some idea of the result of the polygraph test.

Let me tell you what is a polygraph test so that you can have a superior idea of PolygWeb test.Comprising of six sensors, a polygraph is a machine that is attached to the person’s body, whom we are testing. Then number of questions are asked to observe and record the various emotional and physical reactions. The expert who examines the person is known as a forensic psycho physiologist. He observes and records the reactions according to the changes occurring in the person’s body. The polygraph test is also known as to “lie detector test”. It can detect if the person is lying or not. The physiological and psychological conditions experienced by the person during questioning, make the examiner to come to the conclusion. Because various researches have proved that there are changes in the heart rate, the person starts sweating and whole body produces indifferent reactions when a person lies. Thus, we can say that the science is too advanced that we can’t cheat anyone more. The results of a polygraph test are assumed to be 98-100% accurate and this accuracy increases their use in the various fields like for criminal investigation, in courts, in relationships, in industries to check the truthfulness of the employees and many others.

Moreover, you must have come to know the importance of PolygWeb test. It is online testing or screening of the person before the polygraph test starts, which can make him know the results of the polygraph test in advance. And in the case, the polygraph test is compulsory for the person, it also gives him the opportunity if he can manage to make some changes about that because it is assumed that anyone can cheat the polygraph test by having full preparation and proper training.

Benefits of PolygWeb test

  • The major benefit is that it lets you decide if you should go for polygraph test or not as it illustrates that whether the result of polygraph test will be positive or negative.
  • If it is sure that a person have to go through the polygraph test, then having the PolygWeb test can beat the polygraph test in the case the subject somehow manages to transform its negative results into positive ones.
  • On the contrary,the PolygWeb test can also be beneficial for the different authorities using polygraph tests to detect loyalty of their human resources. For instance, if the result of both the tests is same or opposite, the authority can come to know about their truthfulness and cheating respectively.