The polygraph test, also known as lie detector test, is a method by which a person’s physiological indices are measured and recorded while being asked a series of questions. These indices include, but are not limited to, blood pressure, pulse, respiration, and skin conductivity.
A person is believed to have varying physiological responses depending on his thoughts. This is where lie detector tests are anchored. It is believed that these responses will be able to reflect the truth or falsity of a person’s statement.

Brief History
Humanity’s quest for wanting to know the truth dates back to the Middle Ages. Back then, torture was used to elicit information from a person’s lips. Luckily, these are no longer sanctioned in these modern times.
Fast forward to 1895, a device invented by Cesare Lombroso was used to aid police cases in determining a person’s blood pressure.
Later on in 1904, Vittorio Benussi created a device, which was capable of measuring a person’s breathing. However, it was not until 1921 that the lie detector known today was conceived. It was created by Dr. John Augustus Larson, a medical student from the University of California, Berkeley and was able to measure both blood pressure and breathing.
This device was used to aid the Berkeley Police Department in their law enforcement duties. In 1945, John E. Reid added features to Larson’s prototype, allowing it to record a person’s blood pressure, pulse, and respiration simultaneously. Reid believes that these simultaneous recordings will offer greater accuracy and success.
Research reveals that polygraph results, as long as it is conducted by qualified professionals, can have an accuracy between 75% and 95%. This percentage is enough to determine a person’s opinion on a certain matter, and could come in handy in certain situations.
Being one of the biggest phenomenon at the beginning of the 20th century, these lie detector tests have reached a wide set of users from various countries.

In the United States alone, certain courts are allowed to admit polygraph test results as evidence, although still subject to the sound discretion of the trial judge. Additionally, the device is also widely accepted by prosecutors and law enforcement agencies as a means to extract the truth from suspects during investigation. Other officers also take advantage of this technology during post-conviction supervision, particularly those who have been convicted of sexual offenses. Outside the United States, only a few countries have embraced polygraph test results as an accurate evidence.
Outside the realm of judicial application, lie detector tests are also used by some employers in screening out potential employees. They believe that this examination would help keep their employees honest, which would help in the general upkeep of the company.
Another use for these polygraph tests is as an aid in conducting another social examination. These tests may be used before and after interviews to check if a person’s level of nervousness has affected the way he answers during an interview.
Polygraph and Society
Mass media has played a vital role in the popularity of polygraph tests. They are often depicted in fictional films and television series as a reliable source of truth from various informants. This is especially true in detective and mystery-solving dramas.

Several reality shows and talk shows have also engaged the use of lie detecting machines to gather the truth from guests. However, data gathered would often be considered merely as a source of entertainment, and not as incriminating information.

There are also known game shows that utilize this technology in testing whether the contestant would qualify for a prize. Contestants are challenged with a set of revealing questions which they must answer truthfully. If they succeed, they are to take home generous cash prizes.

The growing popularity of these polygraph tests has also made it into a party staple, with portable versions of these machines being sold in toy shops. The toy uses the same algorithm to determine a person’s heart rate, and is programmed to emit a minor shockwave if the person answers with a lie. Results of this portable lie detector may not be as accurate, but it is a great way to keep guests entertained and get acquainted.


Modern technology has improved the results of today’s lie detector tests. It is undeniable that these results still provide an accuracy between 75% and 95% – a number still below absolute certainty.

With that said, the reliability of lie detector results as evidence is met with great caution. They are often considered only as a factor in determining the honesty of the accused in answering statements, but not as something which would absolutely convict him of guilt beyond reasonable doubt.

Nonetheless, the accuracy rate of these results is already enough in certain situations. These include determining the honesty and sincerity of job applicants, or as a source of entertainment in social gatherings.