Kulsoom Ruma, Ph. D. Scholar, Aligarh Muslim University (AMU), Aligarh
The investigating agencies must carry out exhaustive inquiries and compile reliable evidence to successfully investigate and convict an accused person in a criminal case. In complex criminal investigations, investigating agencies frequently turn to psychological testing to bolster their findings and make judgments about whether the suspect is telling the truth in light of the evidence.
Instead of using the third-degree traditional method, which not only violates fundamental human rights but also is unable to produce appropriate results in most cases, the prosecution agency must rely on something more genuine, more real, and more creative in order to secure convictions. As a result, lie detectors became a part of modern science with the development of the 20th century. This is due to the fact that criminals are considering new techniques in the commission of crimes.
A device that measures a number of physiological changes that take place during the operation is utilised in polygraph testing. From the pattern of these measurements in their responses to the questions on a polygraph test and occasionally with the use of observations made during the polygraph test, examiners can determine a person's psychological state, specifically whether they are speaking the truth or lying. According to science, the conscious sensation of guilt triggers a defence response that manifests as physiological changes in the skin's electrical resistance, also known as galvanic skin resistance, as well as heartbeat, blood pressure, and breathing rate. Usually, a person lies out of fear of being discovered and captured. The mental excitement is the result of this psychological phenomena. The 'defence mechanism,' as it is referred to physiologically, is the person's attempt to hide the stimulation. This action activates the adrenal glands, which release the chemicals adrenaline as a result. When this hormone enters the bloodstream, it raises the person's blood pressure, heart rate, and breathing.
