In a big development in the Sunanda Pushkar case, a Delhi court has allowed polygraph test on three “suspects”, who are being accused by the Delhi Police of lying in the case.
- However, the court set a condition that the guidelines laid down by the National Human Rights Commission and the Supreme Court should be followed in conducting the procedure. The guidelines stipulate among other things that the lawyer should be present.
Lie Detector and Polygraph Tests:
Lie detectors are called polygraphs because the test consists of simultaneously monitoring several of the suspect’s physiological functions –
- Pulse, and
- Galvanic Skin Response — and printing out the results on graph paper.
- The printout shows exactly when, during the questioning period, the biologic responses occurred. If the period of greatest biologic reaction lines up with the key questions on the graph paper – the questions that would implicate the person as being involved with the crime – stress is presumed. And along with this presumption of stress comes a second presumption: that the stress indicates a lie.
- Lie detector tests or polygraph tests are rarely used in criminal trials. The theory underlying a lie detector test is that lying is stressful, and that this stress can be measured and recorded on a polygraph machine.
However, the courts in most jurisdictions doubt the reliability of lie detector tests and refuse to admit the results into evidence.
Supreme Court’s views:
The Supreme Court of India in 2010 had ruled
- compulsory brain mapping,
- Narco-analysis and
- lie detector tests unconstitutional as they violate individual rights.
The SC had said that the tests can be administered to a person only with consent and even then National Human Rights Commission guidelines must be adhered to. The person needs to be assisted by a lawyer, his consent needs to be recorded before a magistrate, and he needs to be told about the implications of his consent and the fact that the information thus collected would not be used against him as evidence in court. But information or material collected with the help of a (voluntary) test can be admitted in court under section 27 of the Evidence Act.
Sources: The Hindu, Wiki, SC.