We all know what a lie detector is. It is a machine that assists professionals in determining whether a person is telling the truth or not. This machine that is a polygraph has a long history behind it. Here we shall look at how the polygraph originated in brief.
It all started when physiological changes in relation to deception started being studied in the 20th century. In early 1900, Vittorio Benussi started developing the first tests due to the establishment of a relationship between an increase in the rate of respiration and lying. N E Burtt next confirmed a positive relationship between an increase in Blood Pressure and deception as well. A sphygmograph was eventually developed to record the Blood Pressure of suspects over a chart to notice the change in blood pressure over a period of time.
Later in the 21st century, facial and behavioral changes were also studied. People lying are supposed to have a higher pitch, increased pupil size, more blinking and a nervous posture. Machines for recording these changes have also been developed but are less common in use.
In spite of all these developments, polygraphs are yet not considered 100% reliable. This is because the physiological changes of the body are not necessarily controlled by the conscious mind. Many a time the reactions produced within the body are unconscious and can lead to false results.
However, the use of lie detector test as an effective lie detection aid cannot be underestimated. Lie detection tests sound intimidating but can help resolve a lot of problems especially when someone is under suspicion or is being accused.
It is also important to note, that the results produced by polygraphs are not independent. They are analyzed and studied by a professional practitioner who is trained in reading and interpreting the graphs. So, in general, it is safe to assume that lie detector test results are reliable to a great extent.