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Shraddha Murder Case: What is Polygraph test? How does a lie detector work?

Shraddha Murder Case: What is Polygraph test? How does a lie detector work?

When a person gives deceptive answers (or lies), his or her physiological responses differ from when he or she states the truth and that's when a polygraph test comes handy.

The test's underlying theory is that telling the truth would cause a different physiological reaction than lying would. The test's underlying theory is that telling the truth would cause a different physiological reaction than lying would.

On November 21, the Delhi Police were granted permission to conduct a polygraph test on Aaftab Poonawala, the accused in the murder of Shraddha Walkar.

A polygraph test, also known as lie detector test, includes devices such as cardio-cuffs and sensitive electrodes attached to the person being tested. While he or she is asked specific questions, the instruments measure and record blood pressure, blood flow, pulse, respiration, breathing rhythms, skin conductivity, perspiration, and arm and leg movement.

When a person gives deceptive answers (or lies), his or her physiological responses differ from when he or she states the truth. The investigators monitor the changes in the person's body, breathing pattern, and heart rate.

According to Psychology Today, the first polygraph was created in 1921 by John Larson, who combined previously made methods of measuring respiration, heart rate, and blood pressure that had each shown promise as a measure of lying.

How does it work?

According to CBS, a subject's chest and abdomen are covered with rubber tubes to measure respiratory activity, their fingers are fitted with tiny metal plates to record sweat gland activity, and their cardiovascular system is observed using a blood pressure cuff or a similar device.

The test's underlying theory is that telling the truth would cause a different physiological reaction than lying would.

Aaftab is charged with killing his live-in partner Shraddha Walkar in May 2022. Aaftab is accused of killing Shraddha, then cutting her body into 35 pieces over the course of 18 days. The nation was shocked when the murder's gory details were made public more than five months after the crime.

Also Read: Aaftab Poonawala's lawyer says he hasn't confessed that he murdered Shraddha Walkar

Also Read: Aaftab Poonawala says he killed Shraddha Walkar 'in heat of the moment'