Lie detection is something that people from the past have been talking about. Be it anyone involved in crime or similar activities, people held guilty are always in the line of choosing to be lying to the authorities despite being caught red handed. However, the law demands proof and the lie detector test is one way to find this out.

The lie detector test, which is also known as the Polygraph test is something that measures, records and analyses carious physical and physiological measures to detect truth or lie said by any individual while answering to a set of questions. The various factors which are analysed are:

  1. Blood pressure
  2. Pulse
  3. Respiration
  4. Skin conductivity

The Polygraph was introduced in the year 1921 by John Augustus Larson. He was a medical student pursuing his degree from the University of California, Berkeley. It is known to be the greatest inventions of all time in the history of the world.


There is an examiner who knows how to operate the polygraph machine and uses various tools and techniques to make the other person comfortable. Various preliminary questions are then asked from the person which helps the examination to be conducted at a later stage.

To start off with, there is a Stim Test which involves the person to lie so as to check the authenticity of the polygraph machine. A series of questions are asked to the person by the examiner and the test takes place. The person in question becomes all the more conscious when the Stim Test is conducted to validate authenticity. However, it has been proven that innocents are more anxious than the guilty ones.

Then, the actual test starts. There are basically three main types of questions that are put up which are:

  1. Irrelevant Questions – for eg. Is your name John?
  2. Diagnostic Questions
  3. Relevant Questions

The examiner first asks the irrelevant questions which are followed by the diagnostic questions, and the remainder are the relevant questions which are of great help to the examiner during the course of the test. The test is considered to be passed when the responses to the diagnostic questions are more psychological than the relevant questions.

There are various criticisms with regard to the set of questions that are put up to the other person in lieu of the examination done. However, there has been no proof as to why these questions cannot be included in the set and thus, they are still the most apt ones. An alternative to this is the GKT – Guilty Knowledge Test.

The Guilty Knowledge Test involves questioning in such a way that it takes out the potential as well as the mini errors that may have arisen due to the style of questioning. The examiner conducting the test is someone who does not have any knowledge in the field of crime. It is most commonly used in Japan. The questions presented thereof are multiple choice questions and the person held guilty is rated on the basis of these one word answers. If the answers are strongly in contention with the crime scenes, then the person held responsible is found to be guilty and strict action is taken immediately.


The lie detector test may have been put to use by various countries and agencies all over the world, but it is widely criticized as well. There are various criticisms with regard to the set of questions that are put up to the other person in lieu of the examination done. Also, a number of such tests have been proven to give false results. Thus, the polygraph test is not completely foolproof and hence, cannot be totally relied upon as well.


There are a few countries around the globe that make use of the polygraph test. Those are listed as:

  • Canada
  • United States
  • India
  • Israel
  • Australia
  • Europe
  • Japan
  • China
  • Indonesia
  • Russia

Also, various organizations that use the lie detector tests are:

  • Intelligence Bureau
  • Central Bureau of Investigation
  • Federal Bureau of Investigation
  • National Intelligence Agency
  • Crime Investigation Department


It is, however, quite difficult to understand the mechanism and working of the lie detector test as to how a machine can tell the difference between truths and lies. There have been many contradictions on the internet related to this, but the actual thing behind it still remains a mystery. Many scientists are believed to have found an alternative to the polygraph test, but none have been successful in doing so.

A machine may or may not tell the exact truth, but researchers believe it is the most effective way to detect the difference between truth and lie in the modern era and today’s times.