Polygraph test

In news: Delhi Police approached a court to conduct a polygraph test on Aaftab Poonawala, suspected of killing his partner Shraddha Walkar, to help investigators find the missing weapon and other evidence in the murder case.

About polygraph test:

• A polygraph test is a lie detector test.
• It assumes that physiological responses (heartbeat, changes in breathing, sweating, etc.) triggered when a person is lying are different from what they would be otherwise.
• Instruments like cardio-cuffs or sensitive electrodes are attached to the person, and variables such as blood pressure, pulse, blood flow, etc., are measured as questions are put to them.
• A numerical value is assigned to each response to conclude whether the person is telling the truth, is deceiving, or is uncertain.
• First done in the 19th century by the Italian criminologist Cesare Lombroso, who used a machine to measure changes in the blood pressure of criminal suspects during interrogation.
• Neither polygraph tests nor narco tests have been proven scientifically to have a 100% success rate, and remain contentious in the medical field as well.
• The results of the tests cannot be considered “confessions”.
• However, any information or material subsequently discovered with the help of such a voluntarily-taken test can be admitted as evidence, the Supreme Court said, in ‘Selvi & Ors vs State of Karnataka & Anr’ (2010).
• No lie detector tests should be administered except based on consent of the accused.
• The consent should be recorded before a judicial magistrate.
• Those who volunteer must have access to a lawyer, and have the physical, emotional, and legal implications of the test explained to them by police and the lawyer.
• the ‘Guidelines for the Administration of Polygraph Test on an Accused’ published by the National Human Rights Commission in 2000, must be strictly followed.
• The Supreme Court took into consideration international norms on human rights, the right to a fair trial, and the right against self-incrimination under Article 20(3) of the Constitution, as it is feared that a false confession could be obtained at times when a case needs to be solved quickly.
• A forcible intrusion into a person’s mental processes is an affront to human dignity and liberty, often with grave and long-lasting consequences.

Source: Indian Express