London Polygraph

The polygraph commonly referred to as “lie detector” is a machine used to in lie detection techniques. The polygraph measures certain physiological changes such as blood pressure, pulse, respiration, skin conductivity etc that helps in differentiating the truth from the lies when the examine is asked to answer a series of questions. The polygraph was listed as one of the best inventions in the 2003 Britannica encyclopedia for the profound impact it has had on the human development and society as a whole. However, the potency of the device is much debated in the scientific community. A sizeable faction of the scientific community believes it to be pseudoscience. The device is supposed to yield accurate results but only for specific events and not under all circumstances. The device can prove to be ineffective if the subject is trained in counter-measures.

The device currently is being used by law enforcement agencies all over the world as an interrogation tool. Several government agencies like the FBI, CIA, and even police departments employ the polygraph method to help solve crime; it is also used to screen employees.


History of the polygraph:

John Augustus Larson invented the polygraph in 1921, a medical student at the University of California, Berkeley. The device was further improved on by his protégé Leonarde Keeler. Keeler made the device portable and added certain notable features such as galvanic skin response; the updated device was later bought by the FBI.

How does the polygraph work?

Polygraph works on the principle of certain physiological changes occurring to the subject when he/she is posed with a series of questions. The test begins with an examiner asking three or four questions to set the norms of the test. This will later be used to prepare “diagnostic questions”. The subject is asked to lie deliberately and is then informed that the device is working correctly. Reminding the validity of the test makes a person who’s guilty anxious. However, there are equal risks for innocent people as well. The Control Question technique (CQT) has received criticism for its interrogation style of questioning. This style could even make an innocent nervous and elicit a physical reaction. Guilty Knowledge test(GKT) or Concealed Information test(CIT) are known to be more reliable. Here the tester has no knowledge about the crime. This way the tester’s ability to affect the results is greatly reduced.

The test ultimately checks for any physiological changes like an increase in the subject’s Blood pressure, breathing rate, perspiration etc. A well-trained examiner is better at detecting lies and is more accurate.


There are many reasons why you may require the services of an Institute that provide lie detection tests. Here’s to name a few –

  • To find out whether a partner is faithful in a relationship.
  • If you are falsely accused of crimes.
  • To catch culprits who are committing fraud in your company etc.

There are hundreds of London polygraph institutes that offer such services. Most companies can travel to your location and perform the test discreetly and as per your requirements. You can schedule an appointment and get rid of any problem that has been gnawing at you for a long time.

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