Wednesday, 27 December 2006

The truth about polygraph, nacroanalysis and brain-mapping

By Syed Akbar
Hyderabad, Dec 27: The ultra-modern narcoanalysis and brain-mapping are not as effective as the age-old polygraph or lie-detector test in establishing a criminal act.
Even as the special TADA court has permitted the CBI to conduct narcoanalysis and brain-mapping on mafia don Abu Salem, forensic experts in Hyderabad feel that the tests will not reveal anything new to the investigating agency. "The tests are not only unethical but also unreliable. They are not foolproof and the evidence is not applicable in a court of law," says a senior official of Andhra Pradesh Forensic Science Laboratory.
Brain-mapping and narcoanalysis are carried out in India at only two forensic science laboratories in Bangalore and Ahmedabad since the tests involve risk to the life of the accused undergoing them. Though the APSFSL
has the facilities it is not carrying out these tests as forensic officials do not want to "waste" time on something which is not "standardised".
During his recent visit to the city Dr Farevell, who invented the technology, admitted that it was not as effective as the basic lie-detector test. Asked why he had not standardised the technology, he pointed that a news photographer, a reporter, an investigating police official and criminal, if subjected to the test, would give the same brain patterns since all of them had witnessed the crime or visited the scene of offence. "If this is the case how can you standardise the test," he shot back.
The narcoanalysis test is conducted on the presumption that a person under the influence of intoxication (like a drunkard) would always speak the truth. "We all know how much truth a person under the influence of alcohol will reveal. Similar is the result of narcoanalysis test," the forensic official said.
To illustrate the ineffectiveness of these two tests, the official, giving the example of stamp scamster AK Telgi, pointed out that though he had undergone the tests thrice the investigating agency could not recover even Rs 1 crore of the Rs 24,000 crore scandal. The question posed was why should the CBI make Telgi undergo tests thrice if they were really effective.
On the other hand, the simple polygraph or lie-detector test is generally 90 per cent reliable. If it is carried out by an expert the result is 100 per cent accurate, the official said.
What is narcoanalysis test: Since a person may lie in a conscious state, he or she will be subjected to drugging to suppress or neutralise the imagination or conscious mind. Once the person becomes semi-conscious, it is presumed that it becomes difficult for him to lie. The answers he gives are simple facts.
Narcoanalysis tests are conducted only with the permission of court since risk is involved. A team of medical experts including an anaesthetist and a neurologist conduct the test which generally lasts for two hours.
Before the test begins, doctors inject sodium pentothal or sodium amytal into the person undergoing the investigation. The dosage depends from person to person. Some require higher dosage to "speak out" the truth while others may do with a small amount. A wrong dose may throw the person into coma or even death.
Once the medicine starts working, the investigating officer puts questions which are generally specific and simple. Since the person is semi-conscious, police officials believe, whatever he or she speaks is truth and nothing but truth. The answers are said to be spontaneous.
Brain-mapping or P300 test: This investigating test is based on the electric impulse or wave generated in the brain when a person recognises something.
This test also involves expertise as any small mistake will cause harm to the person. Sensors are attached to the head. The person is asked to sit before a computer monitor. Computerised images and sounds are played and experts ask the person to recognise them. The electric waves generated when the person really recognises the pictures or sounds are different when he pretends not to know them. The sensors attached to the head record the electrical activity in the brain and register P300 waves. The P300 waves are generated only when the person recognises the images or sounds.

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