he Supreme Court has banned the lie-detector, Narco analysis and brain mapping tests. The judgement is viewed as a blow to the investigative agencies which have been restrained from “intruding into an individual’s personal liberty”.The court has upheld and endorsed the age-old and time-tested dictums, guaranteeing the right of the accused to making a “choice between remaining silent and speaking”; protection against “self-incrimination”; and exercising one’s human right “to refuse a medical test being unwarranted intrusion into personal liberty”.
The court did not find favour with the projection of demands of employing the banned deception detection techniques as averments, even if investigation is imperative in the interest of sovereignty and integrity of India, which the court termed as “hypothetical”. It has also gone to the extent of even interpreting the fact of the acceptance of three techniques of lie detection, Narco analysis and brain mapping as being capable of prejudicing the mind of the trial judge; and also that, such presumptions on the part of the court would stigmatise the accused.
The baggage of truth is always heavy. Hence a few people carry it whereas a guilty human mind prides and survives on lies, which are stashed somewhere to be detected. But as the court intends it to be done, it is not without enough caution and exercising due diligence. The ruling has evoked mixed reactions making it expedient to put things in proper perspective.
“It is fitting that a liar should be a man of good memory”, says Quintilian. Basing their endeavour on this principle, the deception detection experts all over the world seek to know the truth, when it is embalmed or clouded. There can be innumerable theories with regard to the tendency in man to hide the truth as there can be a thousand explanations for this. But here we will deal only with cases involving willful suppression of the truth and try to see how the truth can be exhumed, with the help of the deception detection techniques currently prevalent and as being resorted to by the investigating agencies, initially as an aid to investigation, to be later on padded with corroborative evidence to be led in a court of law.
The polygraph is a graphic description of what biological changes take place in a suspect, regarding his pulse rate, perspiration, EEG, blood pressure, voice modulation etc. This graphic representation indicates what goes on in the subject’s mind at a point of time when he is accused of a certain undesirable behaviour and that when he is being subjected to the test, he is supposed to tell the truth but indulges in hiding it, through conscious effort. The physiological changes that take place in the person’s body are measurable.
The changes are visible on the face too, for example, sunkenness, stretching, twitching, paleness, bulging of eyes, drying of tongue, broken speech, etc. The subject’s actions are such as would not seem normal — tremors, trembling, tapping the ground with the feet and throwing off the limbs in various directions out of anxiety.
The subject’s mind is still not known to the scientist, expert or the investigator. For this, certain medical aids are required and the first generation of polygraph had four types of graphs needed to know the limits of blood pressure, pulse rate, respiration and perspiration. These are involuntary activities and one cannot hide these natural biological responses, unless one is a hardened criminal or has practiced the art of suppression of facts without having to allow these changes to occur or get recorded.
While putting the lie-detection technique into practice on a subject, one gets a normal graph till no “offending and involving questions” are asked. The subject’s blood pressure, respiration, pulse rate and sweat discharge tend to vary with uncomfortable questions that disturb his state of mind which instantaneously and with a biological process manifest themselves into measurable graphic presentations.
“Controlled questions” are queries about which the answer is well in hand, but your subject replies in a very guarded language and mostly contrary to the truth. Here, the polygraph comes to the expert’s rescue for it has already recorded the changes in the graph which appear different from the normal. It goes without saying that there is a certain correlation between the incident and its associated environment, i.e. a crime and its scene.
Suppose a murderer is being polygraphed. You know his probable involvement in the crime. Instead of putting a straight question, “Did you really commit that murder?”, you put a question like this: “Do you live somewhere near Mr X’s house (where the murder was committed)?”
Though you have not directly accused your subject, the graphic biological changes enable you to assume that the subject has become “anxious” and is not “at ease with himself” with the question, and is trying to suppress the truth.
For putting questions to the subject, one has to have standardised questionnaires prepared, in consultation with a psychologist, which he thinks will bring out the desired responses, from the subject, when drafted scientifically and systematically, in a sequential manner. Making assessments and assuming without developing any standard correlations so far as human psychology juxtaposed with criminal behaviour is concerned, it does not help on a polygraph.
Another component added, though lately, to the polygraph is in the form of an electro-encephalogram (EEG). Besides the other four components, the EEG provides a graph on the functional aspect of the brain while the lie-detection test is on. Though EEG is a very sensitive equipment, with the help of the standardised questionnaire, it helps in giving out a pattern of graphs of how the brain reacted to certain queries. But if the subject is suffering from epilepsy or other diseases related to the functional aspect of the brain, the desired results may not be coming forth.
Yet another addition to the polygraph was in the form of the Voice Stress Analyser (VSA). In this scheme, a very sensitive microphone is placed in front of the subject’s mouth to record the vibrations produced while speaking. Audio perceptions beyond the reach of the human ear are graphed meticulously on the VSA and all accents, pitch-variations, voice-modulations, thought-blocks and articulations are noticed which add new meaning to the stress-evaluation technique. In the VSA, two properties of the voice or the sound produced are important. These are pitch and frequency. For one articulation, they differ from man to man.
The salivation-measuring technique could never be added to the polygraph. The Chinese have been known historically to be using an indigenous and unique way of lie detection and that being assessing drying of the mouth, as a result of the stoppage of salivation, due to stressful conditions. In olden times in China, the investigators used to put rice powder in the mouth of the suspect while confronting him with the question of his involvement in a crime. He was then asked to spit it out. If there was dampness because of salivation in the spitten powder, the subject was declared innocent.
All detection deception techniques prescribed by modern-day psychologists are endeavours to make the subject shed his introversion and become an extrovert (to put it in simple words) under relaxed conditions. A three-way formula is generally suggested for stress-evaluation on polygraph, Narco analysis and brain mapping. This comprises a pre-set interview, an interview and a review.
As for the accuracy of polygraph, Dr. V.V. Pillay, a professor in AIMS, Cochin, says that “despite claims of 90 per cent and 95 per cent of reliability, a recent survey estimated the test average accuracy of polygraph at 61per cent, which is a little better than “chance”. In 2003, the National Academy of Sciences, USA, issued a report entitled “Polygraph and Lie Detection” which stated that a majority of the polygraph tests was “unreliable, unscientific and biased”. In most countries, the polygraph test is not admissible in evidence unless supported by other corroborative and conclusive evidence.
Coming to Narco analysis, it is said to be an area which envisages many negatives and positives involved in the technology; ethics and legality of the same again remaining questionable. Brain mapping, which involves analysing graphs generated through electrodes on information having been stored, or not stored in one’s brain, is still voted to be more acceptable.
The popular perception as has lately obtained is that with certain necessary ingredients roped in the process of Narco tests, the technique should have counted with the courts in as much as transparency in executing the test is exercised; the log of activities and process is maintained; videography is done; the subject’s free consent is obtained; and he or she be convinced about the Narco administering experts’ objectivity in neither being a witness of defence nor prosecution, but an expert helping the court to arrive at the obtainment of certain facts — is concerned.
Barbiturates (sodium pentothal) or drugs like scopolamine to lessen the subject’s inhibition, shedding his reservations and coming out freely to share information and feelings are administered in the Narco analysis test. This drug was also known as the “truth serum” and was used in 1922 in Texas (US) for the first time by Robert House. Under controlled circumstances of a laboratory, a suspect is injected with hypnotics like sodium pentothal or Amytal, the dose of which to be administered depends on the person’s age, sex and health besides other physical presentations.
Then the subject is not in a position to speak on his own but can answer questions after he is given some suggestions. These tests are generally done by the Forensic Science Laboratories in Bangalore and Ahmedabad. In India, the projections of Narco anaylsis are padded with findings of the polygraph and brain mapping while prosecuting the accused persons.
Of late, the Indian forensic science community has been seen to be swearing by and has even moved on to the refined version of deception detection by Narco analysis called Brain Electrical Oscillation Signature Test (BEOS), popularly known as brain mapping. This technique also called Brain Finger Printing determines, whether specific information is stored in a suspect’s brain or not. It does not give out the details of the crime committed by an accused. But it does give a graphic representation that confirms that the information about the crime is “available” with the suspect.
Now, how come the information is there with the suspect cannot be explained but there is a presumption that the accused knows something about the crime or his misdemeanor. It is done by measuring the electrical brain wave responses to words spoken or picture displayed to the subject.
That the brain processes “known relevant information” differently and “unknown and irrelevant information” differentially, was first invented by Lawrence Farwell in 1990. Such processing of known information like details of crime stored in the brain is revealed by specific pattern in the EEG of that person.
Technically explaining, brain mapping involves confrontation with a stimulus of special significance with electrical signal known as P300, emitted from individual’s brain, beginning approximately 300 million milliseconds after the confrontation. For forensic purposes, P-300 is considered as a response of stimuli related to a crime, for example, a murder weapon or victim’s face etc. Of late, MERMER (memory encoding related multifaceted electro-encephacophic response) is being used which includes P-300 and provides a higher level of accuracy.
Since it is based on EEG signals and graphs, the system does not require the subject to speak at all and he in way continues to exercise his right to keep silent. The suspect wears a special hair band with electronic censor that measure the EEG from several locations on the scalp. He views stimuli consisting of words, phrases, pictures etc. on a computer screen or even directly.
The stimuli are of three types: (i) ‘stimuli’ irrelevant to the investigation and to the subject; (ii) ‘target’ stimuli relevant to the investigation and known to the subject; and (iii) ‘probe’ stimuli relevant to investigation and that the subject denies. These probes contain information that is known to perpetrator and investigators, and not to the general public, or to the innocent suspect. This determination is computed mathematically and does not involve the subjective judgement of the scientist.
Advantages that can be counted of brain finger printing include the fact that they do not depend on the emotions of the subject’s information, nor are they affected by the emotional responses. Also unlike polygraph, it does not attempt to determine whether or not the subject is lying or telling the truth.
It only measures the subject’s brain responses to relevant words or pictures or scenarios to detect whether or not the relevant information is stored in the subject’s brain or otherwise. Probably for this reason over 99 per cent accuracy has been reported in brain mapping in laboratory as also field applications.
With the latest ban on deception detection techniques like polygraph, Narco analysis and brain mapping, the investigating agencies may have suffered a blow in expeditiously reaching out to truth. However, keeping in view the self-incriminating nature of this kind of evidence and consequences of employing these tools on an individual’s liberty, the judgement will not only restore people’s faith in the system but also enhance all right-thinking citizens’ respect for human rights and
values.
The writer, a senior IPS officer of Haryana, has specialised in Technology-Driven Policing. He is also a National Police Trainer recognised by the Bureau of Police Research and Development, New Delhi
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