Perpetuation of a forensic myth
V.V. PILLAY
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Science is yet come up with any effective method of finding out whether a suspect is speaking truth or not
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OF LATE, the Indian media is rife with reportage of "revolutionary" methods of interrogation of suspects, by which the impression is sought to be created that today there are effective scientific methods of ferreting out the truth from culprits of serious crimes. These claims are far from the truth.
As put forth most lucidly in a recent article in The Hindu ("We need to talk about narcoanalysis" by Sriram Lakshman, May 2), science has not yet come up with any effective method of really being able to find out whether a suspect under interrogation is speaking the truth or not, never mind the use of much hyped "scientific" instruments as "lie detectors" or drugs such as "truth serum" or even the new-fangled technologies of "narcoanalysis" and "brain fingerprinting."
The whole saga of scientific detection of deception began with the development of the so-called "lie detector," which was quickly re-named the "polygraph," in the face of criticism that what it actually accomplished was the measurement of certain physiological changes in an individual which allegedly occur when he is lying, and that such changes could well occur even in an individual who is not lying, but merely anxious and nervous. In other words, the polygraph can never really distinguish between anxiety arising out of plain nervousness and that born out of guilt.
The lie detector was quickly followed by the era of the "truth serum." This was another pseudo-scientific bogey that had its origins from the "narcoanalysis" employed by pre-Freudian psychologists to enable psychiatric patients to undergo catharsis, a form of psychological release of pent up emotions.
It involves the administration of certain drugs in a conducive setting to a patient that facilitates him to shed his inhibitions and start talking about matters that have been suppressed in his subconsciousness. Forensic psychologists claimed that the method could also be employed in criminal situations, to get the truth out of the subconscious mind of a guilty individual.
What in fact the method succeeded in doing was only to confuse a person and cloud his consciousness, as a result of which he would start rambling about a number of real and imaginary issues. Some of these could well be unpleasant truths that the individual would normally not talk about, but a lot of it could also be fantasies released by the drugs' influence on the brain. So, how does one sift the chaff from the grain?
It is ironical that when the utility of the so-called truth serum was finally debunked owing to its dismal failure in several criminal cases, some die-hard forensic fans decided to give it a new lease of life under a new avatar — "narcoanalysis."
Whatever one may call it, "truth serum" or "narcoanalysis," the fact remains that it is just another dubious method of getting at information that is taken as true, while in reality, it more often misleads an investigation than guides it in the right direction.
And thus finally, we come to the latest pseudo-scientific fad — "brain fingerprinting." This is a controversial technique that is advocated as a way to identify a criminal by measuring the "brainprint" of that person when shown a particular specimen of writing, or an image that was previously familiar (such as a crime scene).
The brainprint is based on the P300 complex, a series of brainwave components that can be measured. The subject is fitted with a headband equipped with sensors, and shown a series of relevant words or pictures on a computer screen. When the brain recognises something familiar, it elicits a wavelike response known as a MERMER (memory and encoding-related multifaceted electroencephalographic response).
Critics of brain fingerprinting have questioned as to whether the technique could be administered efficiently in a consistent manner without a considerable number of false readings. There have been numerous instances of variable results on the same suspect, when the test was administered by different investigators. While this has been explained as being due to incompetence on the part of some investigators, the question remains: how sure can we be in a particular case that the test was done by a "competent investigator"? And what is meant by "competence" in the context of brain fingerprinting? The ability to pinpoint a suspect as the real culprit, who finally ends up confessing to the crime? What if he does not confess? Do we still go ahead and convict him?
These are indeed disturbing questions. Unless proper answers are arrived at, there is a serious risk of travesty of justice being perpetrated in the name of science.
(Dr. Pillay is Professor of Forensic Medicine & Toxicology, Amrita Institute of Medical Sciences & Research, Kochi)
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