Admissibility of Polygraph tests, Narco-anlaysis test and Brain-mapping test in reference to Selvi’s case
Before answering these questions, it is necessary to examine the evolution and specific uses of the impugned techniques. Hence, a description of each of the test procedures is followed by an overview of their possible uses, both within and outside the criminal justice system. It is also necessary to gauge the limitations of these techniques.
Polygraph Examination
The origin of polygraph examination have been traced back to the efforts of Lombroso, a criminologist who experimented with a machine that measured blood pressure and pulse to assess the honesty of persons suspected of criminal conduct. His device was called a hydrosphygmograph. The theory behind polygraph tests is that when a subject is lying in response to a question, he/she will produce physiological responses that are different from those that arise in the normal course. During the polygraph examination, several instruments are attached to the subject for measuring and recording the physiological responses. The examiner then reads these results, analyzes them and proceeds to gauge the credibility of the subject's answers. Instruments such as cardiographs, pneumographs, cardio-cuffs and sensitive electrodes are used in the course of polygraph examinations. They measure changes in various aspects such as respiration, blood pressure, blood flow, pulse and galvanic skin resistance.
There are three prominent polygraph examination techniques: i. The relevant-irrelevant (R-I) technique ii. The control question (CQ) technique iii. Directed Lie-Control (DLC) technique
Each of these techniques includes a pre-test interview during which the subject is acquainted with the test procedure and the examiner gathers the information which is needed to finalize the questions that are to be asked. An important objective of this exercise is to mitigate the possibility of a feeling of surprise on part of the subject which could be triggered by unexpected questions.
Polygraph tests have several limitations and therefore a margin for errors. The premise behind these tests is questionable because the measured changes in physiological responses are not necessarily triggered by lying or deception. Instead, they could be triggered by nervousness, anxiety, fear, confusion or other emotions. Furthermore, the physical conditions in the polygraph examination room can also create distortions in the recorded responses. The test is best administered in comfortable surroundings where there are no potential distractions for the subject and complete privacy is maintained. The mental state of the subject is also vital. In some cases the subject may have suffered from loss of memory in the intervening time-period between the relevant act and the conduct of the test.
Narcoanalysis technique
This test involves administration of a drug that causes the subject to enter into a hypnotic trance and become less inhibited. The drug-induced hypnotic stage is useful for investigators since it makes the subject more likely to divulge information. The drug used for this test is sodium pentothal, higher quantities of which are routinely used for inducing general anaesthesia in surgical procedures. This drug is also used in the field of psychiatry since the revelations can enable the diagnosis of mental disorders. The use of `truth-serums' and hypnosis is not a recent development. Earlier versions of the narcoanalysis technique utilised substances such as scopolamine and sodium amytal.
Narcoanalysis tests could be requested by defendants who want to prove their innocence. Demands for this test could also be made for purposes such as gauging the credibility of testimony, to refresh the memory of witnesses or to ascertain the mental capacity of persons to stand trial. Such uses can have a direct impact on the efficiency of investigations as well as the fairness of criminal trials.
It is also important to be aware of the limitations of the `narcoanalysis' technique. It does not have an absolute success rate and there is always the possibility that the subject will not reveal any relevant information. Some studies have shown that most of the drug-induced revelations are not related to the relevant facts and they are more likely to be in the nature of inconsequential information about the subjects' personal lives. It takes great skill on part of the interrogators to extract and identify information which could eventually prove to be useful. While some persons are able to retain their ability to deceive even in the hypnotic state, others can become extremely suggestible to questioning. This is especially worrying, since investigators who are under pressure to deliver results could frame questions in a manner that prompts incriminatory responses. Since the responses of different individuals are bound to vary, there is no uniform criterion for evaluating the efficacy of the `narcoanalysis' technique.
Brain Electrical Activation Profile (BEAP) Test
The third technique in question is the `Brain Electrical Activation Profile test', also known as the `P300 Waves test'. It is a process of detecting whether an individual is familiar with certain information by way of measuring activity in the brain that is triggered by exposure to selected stimuli.
The P300 waves test is conducted by attaching electrodes to the scalp of the subject, which measure the emission of the said wave components. The test needs to be conducted in an insulated and air-conditioned room in order to prevent distortions arising out of weather conditions. Much like the narcoanalysis technique and polygraph examination, this test also requires effective collaboration between the investigators and the examiner, most importantly for designing the stimuli which are called `probes'. The test subject is exposed to auditory or visual stimuli (words, sounds, pictures, videos) that are relevant to the facts being investigated alongside other irrelevant words and pictures. The underlying theory is that in the case of guilty suspects, the exposure to the material probes will lead to the emission of P300 wave components which will be duly recorded by the instruments. By examining the records of these wave components the examiner can make inferences about the individual's familiarity with the information related to the crime.
Admissibility of the above techniques in reference to Selvi’s case
The High Court’s Stand before the Judgment
During the past decade, High Courts across the country continued to uphold the use of such tests. The Supreme Court’s analysis aptly demonstrates how those decisions strained legal reasoning and logic by relying on the purported scientific nature of narcoanalysis tests despite the fact that scientific evidence had long discredited the tests purported scientific validity.
The Supreme Court’s decision disagreed with the reasoning of the various High Court judgments in three main areas:
a) The reliability/unreliability of the tests;
b) Self-incrimination protections;
c) Substantive due process rights.
The Supreme Court’s decision is in line with Constitutional requirements and international human rights law. However, the Court also ruled that information “subsequently discovered” from the result of a “voluntary” test can be admitted as evidence. The Indian judiciary has finally recognized and condemned the abusive nature of narcoanalysis, brain-mapping, and polygraph tests specifically, the Supreme Court’s recent decision in Smt. Selvi & Ors. v. State of Karnataka prohibited all involuntary administration of such tests, holding them to be “cruel, inhuman and degrading treatment”. Article 21 protects the right to life and personal liberty, which has been broadly interpreted to include various substantive due process protections, including the right to privacy and the right to be free from torture and cruel, inhuman, or degrading treatment. Hence, the above tests violate Article 21.
In sharp contrast, the Supreme Court raised serious concerns about the validity, reliability, and indeed usefulness of narcoanalysis, brain mapping, and polygraph tests. In questioning the scientific reliability of narcoanalysis, the Court for example stated: “Some studies have shown that most of the drug-induced revelations are not related to the relevant facts and they are more likely to be in the nature of inconsequential information about the subjects’ personal lives.”
The Supreme Court overruled various High Courts in declaring that the administration of Narcoanalysis, brain mapping, and polygraph tests violated subjects’ rights against self-incrimination in contravention of Article 20(3) of the Indian Constitution. According to that article, “No person accused of an offence shall be compelled to be a witness against himself”. Forcing a subject to undergo narcoanalysis, brain-mapping, or polygraph tests itself amounted to the requisite compulsion, regardless of the lack of physical harm done to the subject in administering the test or the nature of the answers given during the tests. During the administration of the test, answers are not consciously and voluntarily given, and since an individual does not have the ability to decide whether or not to answer a given question, the results from all three tests amount to the requisite compelled testimony to violate Article 20(3).
Suggested Guidelines
The National Human Rights Commission had published `Guidelines for the Administration of Polygraph Test (Lie Detector Test) on an Accused' in 2000. According to the majority of the case, these guidelines should be strictly adhered to and similar safeguards should be adopted for conducting the `Narcoanalysis technique' and the `Brain Electrical Activation Profile' test. The text of these guidelines has been reproduced below:
(i) No Lie Detector Test should be administered except on the basis of consent of the accused. An option should be given to the accused whether he wishes to avail such test.
(ii) If the accused volunteers for a Lie Detector Test, he should be given access to a lawyer and the physical, emotional and legal implication of such a test should be explained to him by the police and his lawyer.
(iii) The consent should be recorded before a Judicial Magistrate.
(iv) During the hearing before the Magistrate, the person alleged to have agreed should be duly represented by a lawyer.
(v) At the hearing, the person in question should also be told in clear terms that the statement that is made shall not be a `confessional' statement to the Magistrate but will have the status of a statement made to the police.
(vi) The Magistrate shall consider all factors relating to the detention including the length of detention and the nature of the interrogation.
(vii) The actual recording of the Lie Detector Test shall be done by an independent agency (such as a hospital) and conducted in the presence of a lawyer.
(viii) A full medical and factual narration of the manner of the information received must be taken on record.

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[ 1 ]. Criminal Appeal no. 1267 of 2004, Supreme Court of India.
[ 2 ]. In NANDINI SATHPATHY CASE (AIR 1978 SC 1025), the court held that “relevant replies which furnish a real and clear link in the chain of evidence to bind down the accused with the crime become incriminatory and offend article 20(3) if elicited by pressure from the mouth of the accused”.