Narco Analysis And Brain Mapping Tests

The use of increasingly more sophisticated methods in the commission of crimes has necessitated the development of new technologies and tools to investigate them. Often the offender leaves behind no traces of physical evidence. Brain mapping technique seeks to address the problem of lack of availability of physical evidence to determine the complicity of a suspect. It belongs to the realm of cognitive psychophysiology and is based on an examination of the way in which a person’s brain processes information.

So even if no fingerprints, DNA specimens etc. are discovered at the scene of the crime, the information stored in the brain of the offender is always available for examination. The different ways in which the brain reacts to different stimuli can be used to detect whether a person has information relating to the crime stored in his brain. The test does not establish the guilt or innocence of a suspect. It merely attempts to detect the absence or presence of certain crime related information in the brain. Thus the aim of the test is to overcome deception. It can potentially be used in a much broader range of situations than any of the presently established scientific methods.

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However, the test is fraught with controversy. Doubts are being raised as to its constitutionality given the fact that it compels the brain of an accused to give involuntary responses which may prove to be incriminatory. Also in question is the reliability of the test in proving the complicity of a person. Should the results of the test then be admitted as evidence in court and if so, what should be the probative value of such evidence? This paper endeavours to address these and other related concerns.

II. THE TESTS: A Basic understanding

With the crime graph climbing up a steep rate, the police interrogation techniques play a vital role in extracting the truth from the suspect. Some of the commonly used interrogation methods include the use of hypnosis, truth serum, voice analysis, fingerprint testing, handwriting evidence and DNA analysis. The scientific tools of interrogation namely- the Lie detector or the Polygraph test, the P300 or the Brain Mapping test and the Narcoanalysis or the Truth Serum test are the main three tests that have recently been developed for extracting confessions. These psychoanalytical tests are also used to interpret the behaviour of the criminal (or the suspect) and corroborate the investigating officers’ observations.


It is believed that if a person is administered a drug which suppresses his reasoning power without affecting memory and speech, he can be made to tell the truth. Some drugs have been found to create this ‘twilight state’ in some persons. These drugs are being administered in some countries including India. The term narcoanalysis was introduced in 1936 for the use of narcotics to induce a trance like state wherein the person is subjected to various queries. Under the influence of the drug, the subject talks freely and is purportedly deprived of his self-control and will power to manipulate his answers. The underlying theory is that a person is able to lie by using his imagination. In the narcoanalysis test, the subject’s imagination is neutralized and reasoning faculty affected by making him semi-conscious. The subject is not in a position to speak up on his own but can answer specific and simple questions. In this state it becomes difficult for him to lie and his answers would be restricted to facts he is already aware of. His answers are spontaneous as a semi-conscious person is unable to manipulate his answers.

Truth serums (or sera) are no serum at all. They are drugs sometimes used clinically. A few of the best known drugs are Seconal, Hyoscine (scopolamine), Sodium Pentothal, Sodium Amytal, Phenobarbital. Most commonly used drug for truth serum test is an anesthetic and sedative drug, Soduium Pentothal which when administered intravenously can make a person garrulous and confessional. Injected in continuous small dosages it has a hypnotizing effect on a person whop responds loquaciously when questioned. The narcoanalysis test is conducted by mixing 3 grams of Sodium Pentothal or Sodium Amytal dissolved in 3000 ml of distilled water. Depending on the person’s sex, age, health and physical condition, this mixture is administered intravenously along with 10% of dextrose over a period of 3 hours with the help of an anaesthetist. Wrong dose can send the subject into coma or even result in death. The rate of administration is controlled to drive the accused slowly into a hypnotic trance. The effect of the biomolecules on the bio-activity of an individual is evident as the drug depresses the central nervous system, lowers blood pressure and slows the heart rate, putting the subject into a hypnotic trance resulting in a lack of inhibition.

The subject is then interrogated by the investigating agencies in the presence of the doctors. The revelations made during this stage are recorded both in video and audio cassettes. The report prepared by the experts is what is used in the process of collecting evidence. This procedure is conducted in government hospitals after a court order is passed instructing the doctors or hospital authorities to conduct the test. Personal consent of the subject is also required.


It is an examination, which is based on an assumption that there is an interaction between the mind and body and is conducted by various components or the sensors of a polygraph machine, which are attached to the body of the person who is interrogated by the expert. The machine records the blood pressure, pulse rate and respiration and muscle movements.

Polygraph test is conducted in three phases- a pretest interview, chart recording and diagnosis. The examiner (a clinical or criminal psychologist) prepares a set of test questions depending upon the relevant information about the case provided by the investigating officer, such as the criminal charges against the person and statements made by the suspect. The subject is questioned and the reactions are measured. A baseline is established by asking questions whose answers the investigators know. Lying by a suspect is accompanied by specific, perceptible physiological and behavioural changes and the sensors and a wave pattern in the graph expose this. Deviation from the baseline is taken as a sign of lie. All these reactions are corroborated with other evidence gathered.

The polygraph test was among the first scientific tests to be used by the interrogators.


This test was developed and patented in 1995 by neurologist Dr. Lawrence A. Farwell, Director and Chief Scientist “Brain Wave Science”, IOWA. In this method, called the “Brain-wave finger printing”; the accused is first interviewed and interrogated to find out whether he is concealing any information. Then sensors are attached to the subject’s head and the person is seated before a computer monitor. He is then shown certain images or made to hear certain sounds. The sensors monitor electrical activity in the brain and register P300 waves, which are generated only if the subject has connection with the stimulus i.e. picture or sound. The subject is not asked any questions.

Dr. Farwell has published that a MERMER (Memory and Encoding Related Multifaceted

Electro Encephalographic Response) is initiated in the accused when his brain recognizes noteworthy information pertaining to the crime. These stimuli are called the “target stimuli”. In a nutshell, Brain finger printing test matches information stored in the brain with information from the crime scene. Studies have shown that an innocent suspect’s brain would not have stored or recorded certain information, which an actual perpetrator’s brain would have stored.

The Forensic Science Laboratory in Bangalore is the first center in India which conducts the Brain-mapping or Brain-finger printing test. In USA, the FBI has been making use of “Brain mapping technique” to convict criminals.

III. History of Narco Analysis

Early in the 20th century, physicians began to employ scopolamine along with morphine and chloroform, to induce a state of “twilight sleep” during childbirth. Scopolamine was known to produce sedation and drowsiness, confusion and disorientation, incoordination and amnesia for events experienced during intoxication.

In 1922 it occurred to Robert House, a Dallas Texas Obstetrician that a similar technique might be employed in the interrogation of suspected criminals, and he arranged to interview under scopolamine two prisoners in the Dallas county jail whose guilt seemed clearly confirmed. Under the drug, both men denied the charges on which they were held; and both, upon trial, were found not guilty. Thus, Robert House concluded that a patient under the influence of scopolamine “cannot create a lieaˆ¦ and there is no power to think or reason”. His experiment and this conclusion attracted wide attention, and the idea of a

truth drug was thus launched on the public consciousness.

The phrase “Truth Serum” is believed to have appeared first, in the news report of Robert House’s experiment the Los Angeles Record, sometime in 1922. Robert House thereafter came to be known as the ‘Father of Truth Serum’.

The Barbiturates

The suggestion that drugs might facilitate communication with emotionally disturbed patients first camequite by accident in 1916, when Arthur S. Lovenhart and his associates at the University of Wisconsin were experimenting with respiratory stimulants. At about this time, police officials still attracted by the possibility that drugs might help in the interrogation of suspects and witnesses turned to a class of depressant drugs known as the Barbiturates. Barbiturates were first synthesized in 1903 and are among the oldest of modern drugs.

By 1935 Clarence W. Muehlberger, head of the Michigan Crime Detection Laboratory at East Lansing, was using barbiturates on reluctant suspects, though police work continued to be hampered by the courts’ rejection of drug induced confessions except in a few carefully circumscribed instances.

Three of the barbiturates which are used in narcoanalysis and have seen service as truth drugs are sodium amytal (anobarbital), pentothal sodium (thiopental), and to a lesser extent seconal (seconbarbital). During the Second World War, the technique of the so called truth serum was developed to help soldiers who had broken down under the strain of battle. Gradually a useful mental first-aid technique was developed which helped the unconscious to reveal its secret while the individual was under the influence of the narcotic. It was during this time that Sodium Pentothal was first used as a “truth drug”.

Uses of Narco Analysis Drugs

The uses of narcoanalysis drugs are two fold- they are used as “truth drugs” in police work and also used in the accepted psychiatric practice of narcoanalysis. The difference in the two procedures lies in their different objectives. The police investigation is concerned with empirical truth that may be used against the suspect, and therefore almost solely with probative truth. The usefulness of the suspect’s revelations depends ultimately on their acceptance in evidence by a court of law. The psychiatrist, on the other hand, using the same “truth drugs” in diagnosis and treatment of the mentally ill, is primarily concerned with psychological truth rather than empirical fact.

IV. Constitutionality of Brain Mapping

While S. 53 of the Code of Criminal Procedure enables the police to get an accused medically examined, where there are reasonable grounds to believe that such examination would afford evidence as to the commission of the offence, [1] the same has to be done subject to the constitutional safeguard enshrined in Article 20(3) of the Constitution and accordingly the accused cannot be compelled to be a witness against himself.

The courts have been called upon to adjudicate on the constitutionality of medical and scientific tests on several occasions. In State of Bombay v. Kathi Kalu Oghad, [2] the court ruled that “to be a witness” under Article 20(3) means to “furnish evidence” and this phrase does not have to be used in a larger sense so as to include the giving of thumb impressions, specimens of handwriting or exposing a part of the body for identification. Hence such examinations were permitted.

However, the court went on to say that Article 20(3) is violated when the accused who has personal knowledge of facts imparts that knowledge by means of oral or written statements. In giving his thumb impressions et al, the accused is not giving any ‘personal testimony’ because the impressions, in spite of efforts at concealing their true nature by dissimulation, cannot change their intrinsic character.

It is submitted that brain mapping does not satisfy the above test in its entirety being in certain respects different from fingerprinting and handwriting tests. In brain mapping, the accused is imparting personal knowledge of facts. It is not the information stored in the brain that is being extracted but the response of the brain to certain information that is being fed to it. Though the responses being collected from the brain are unchanging in the sense that they would always be the same for the same input, yet the accused is being made to respond to that input. [3] Further unlike thumb impressions and handwriting the responses of the brain are not of an intrinsic nature.

The test is akin to compelling an accused to give certain information on oath. [4] This is so because the accused is being forcibly put in a situation where he cannot lie and certain information is being put to him, and he cannot help but respond to it, even though the response is not in the form of written or oral statements. However, the response given in a brain mapping test may be said to be a statement in the sense that it adopts some pieces of the information, and not others, by making a positive response to it. [5]

The constitutionality of the test has however been upheld by some of the High Courts. [6] In Ramchandra Ram Reddy v. State of Maharashtra, [7] the court said that Article 20(3) is a safeguard against testimonial compulsion and is invoked in the case of a statement by the accused against himself. In brain mapping the result of the test is a map showing re-actions of the brain to certain target questions and hence there is no statement. [8] The test was further justified on the ground that the conclusions of the test are not incriminatory; they merely show whether the accused has information of the crime or not.

The latter part of the argument is similar to that used in the case of fingerprinting test etc. by Justice Das Gupta in his concurring opinion in Kathi Kalu Oghad. [9] According to him, the evidence of specimen handwriting, thumb impressions or other impressions is incriminatory only when on comparision with certain other handwriting or impressions an identity is established between the two. By themselves they do not incriminate the accused person, or even tend to do so. Hence, in giving them even though the accused may be furnishing evidence but it is not against himself.

It is submitted that this argument may be valid in the case of fingerprinting but is inapplicable to brain mapping. According to its proponents, brain mapping is particularly useful in those cases where no physical evidence is available – for instance, fingerprints lifted from the scene of crime. [10] The record in the brain of the offender will always be available. Here there is no external comparision between two specimens. It is the brain that is making the comparision between evidence (in the form of information) received from the scene of crime and the knowledge of the accused. Thus it is the brain of the accused that is furnishing all the evidence against him.

In Dinesh Dalmia v. State by SPE, CBI [11] the court reasoned that the test does not amount to breaking the silence of the accused by force because even when he is taken to the laboratory against his will, the actual revelation during the test is voluntary. It was also observed that unless such tests are conducted the investigating agency may be unable to come up with clinching evidence against the accused. It is submitted that this reasoning is flawed as the revelation during a brain mapping test is not voluntary. The responses which are used for generating the map are completely involuntary the accused having no control over their emission.

The importance of the test for investigation purposes cannot be used to justify it if it is otherwise not permissible. It is submitted that brain mapping is violative of the rights of the accused person under Article 20(3). Unlike other established methods of examination like DNA profiling, fingerprinting, handwriting analysis et al it requires a positive response from the accused.

V. A Comparative Perspective On Brain Mapping Methods Adopted In India And In The U.S.A.

The brain mapping technique is based on the scientific fact that during waking periods the brain receives and classifies innumerable signals, received in different sensory modalities, depending upon their relationship with existing knowledge and experience. This classification or encoding process is different when a person directly participates in or experiences the event from when he gets to know about it from secondary sources. Accordingly, when information relating to the former is fed into it, the brain would be activated differently than in the case of the latter. Consequently, if a person has participated in the crime, the responses he would give to crime related information would be different from those given by a person wholly unconnected with it when subjected to the same inputs.

Farwell’s Method [12]

The information used to evoke a response is divided into irrelevants (or neutral), targets and probes. [13] Targets consist of information which is well known to the subject and they are used to obtain a baseline brain response (MERMER [14] ) which can be used for comparision with responses generated to crime relevant information in order to see if that is equally well known. Irrelevants, which are not related to the case, are used to establish another baseline – to determine if the information is absent. Probes, being the most significant, relate to those aspects of the crime which only a person who has committed a crime would be in a position to know. This part of the information is kept completely confidential.

Before the test is done, there is an interactive session with the subject where he is presented with the list of targets and irrelevants. In this screening process, the suspect is asked if any of the irrelevants are of particular significance to him so that those may be eliminated from the list, else they would show “information present.” He is also told that he would have to press the right button when a target is presented. This ensures that the subject is concentrating on the information that is being presented.

Further, the probes are described to the subject without telling him about the actual input. This contextualizes the information being presented as a probe. Describing the probes also helps in finding out whether the subject already knows about that information – for instance he may have come to know about the murder weapon from the police. If this is the case, then both the criminal and the innocent person would test positive with respect to that information. So such probes are not presented.

For the actual test electrodes are placed on the head of the subject and a four channel EEG amplifier is used to receive the signals. Whenever a probe or a target is presented the brain generates an Event Related Potential (ERP) response. [15] P300 is one component of this ERP which is associated with concealed information. An ERP is detected through an averaging process that eliminates all activity which is not time locked to the stimulus, and along with it other complicated patterns associated with information processing are eliminated as well.

Through a new analysis (MERA [16] ) multiple facets of the data can be analysed simultaneously, rather than obtaining just an ERP, as in the case of the earlier process. Dr. Farwell has identified a particular multifaceted electroencephalographic response called MERMER which is given out by the subject if the stimulus is particularly significant. MERMER consists of not just P300 but also some other components [17] which increase the statistical reliability of the test.

The MERMER elicited in response to the probes are then compared to the baselines. If they are closer to the baseline response for targets then it implies that information related to the probes was present while if they are closer to the irrelevants it indicates that the information was absent. A software is used to determine the statistical confidence in the result. Dr. Farwell claims brain mapping can give results with a statistical confidence of 99.9%. [18]

How the Indian Technique Deviates from Dr. Farwell’s Method

Firstly, in India instead of a four channel EEG, a 32 channel one is used. So while Dr. Farwell notes responses from only four regions namely – midline frontal, central, and parietal locations on the brain, and a location on the forehead to track eye movements, in India the response is being recorded from 32 points – 30 of them cephalic, the other two being vertical and horizontal eye movements. This means that signals encoded in response to not just visual or auditory inputs but other factors like physical experience etc. can also be accessed for the purposes of evoking a response. In this respect the Indian technology is more advanced than the American one.

Secondly, in India only the P300 component is used for analysing the response. In the U.S. also only P300 component was being considered before Dr. Farwell discovered MERMER which is supposed to give more accurate results. However, he has patented the knowledge with respect to MERMER has hence it is unavailable for use by the general public.

On the other hand, use of MERMER suffers from a limitation in that it requires the subject to sit still, or else it is difficult to collect the data. This is because the filtering of response in MERMER is less than in the case of ERP. Artifacts [19] caused by minor movements can be eliminated in data analysis but the subject cannot make major movements. Dr. Malini also argues that even though a lot more waves are being generated in MERMER testing yet Dr. Farwell has not been able to find a use for some of them.

Thirdly, in India the accused is not required to press any buttons in response to any of the information presented to him. The subject is just asked to relax, close his eyes and listen, if the input is in auditory form, and to watch the pictures on the computer screen. Thus, unlike in the U.S., in India nothing is done to ensure that the subject pays attention to the information being presented to his brain. It is possible that he may become distracted or may completely tune out. Further, the subject is kept in a separate sound proof room during the test. Nobody would know if he is not looking at the computer screen.

The problem is further aggravated by the fact that the baseline EEG and ERP responses are not taken with as much care as in the U.S. According to Dr. Malini, a baseline EEG with eyes closed and open are taken to evaluate the normal activities. In the U.S. two baselines are taken – one to gauge the response when the subject is particularly well informed about something and the other for situations where the subject was unconcerned with the input. So it is easier to compare whether the subject knows about the probes or not.

Also, the baseline is computed for normal activities with eyes closed and open. This means that if the subject is not looking at the screen but staring somewhere else, his brain would continue to give the baseline response and he would test negative for the information. If the baselines are to be computed using his response for the kind of irrelevant information that is going to be fed to him, the tester would be able to detect when the subject tunes out as the response would then go below the baseline for irrelevants.

Fourthly, in India a polygraph test is also done during the interactive session to check whether the subject is lying. This is supposed to be helpful in deciding the probes to be used. However, it again raises questions of constitutionality of the test, especially so because the subject is being forced to make oral statements.

VI. Limitations of Brain Mapping

Dr. Farwell acknowledges that brain mapping may not be helpful in several situations. The test only detects the presence or absence of information. Hence, it can be used only to place the person at the scene of crime. Where two suspects were present at the scene of crime, but the crime was such that only one person could have committed it, the test would be inapplicable as information would be present in the brains of both the suspects. The test would not be able to distinguish between the witness and the perpetrator. [20]

Similarly, since the test does not indicate how the information got into the brain, it cannot be used in those situations where the person possesses all the information by virtue of some other fact than being the perpetrator. For instance, the investigators may in the course of investigation have divulged all the available information, [21] or due to the passage of time the public may have become increasingly more aware of details, especially if the crime had received extensive media coverage. [22] However, Dr. Malini emphatically refutes this point. She feels that the response of one who actually committed the crime would always be different from that of a person who merely witnessed it.

Secondly, the test would not be definitive where the investigators do not have sufficient information about the crime. Then there would not be enough information against which the knowledge of the suspect can be tested.

Thirdly, the test cannot be used where the suspect is suffering from a mental illness because he would not be able to process the information the same way as a normal person. [23] There is a possibility that it might not work for habitual offenders also. [24] Further, it is believed that if the subject is under the influence of certain drugs at the time of the test, his memory may be affected. [25]

Fourthly, the test is time consuming and requires a properly trained expert who is able to do considerable detective work as well. [26] Dr. Farwell feels that if brain mapping has to be used extensively, it will necessitate a shift in the way crimes are investigated and will require a trained expert to work on the case from the time the investigation starts so that he may identify the appropriate information and keep it confidential till the test is done. [27]

Fifthly, it has been observed that P300 is a good index of recognition, but an indirect index of deception. [28] When a person denies any knowledge of the murder weapon but still gives a P300 response, it does not lead to an infallible inference that the person is lying but merely indicates that for some reason the weapon is special or recognizable by him. It may be because he possesses a similar one himself, or has extensive knowledge of guns generally.

VII. Reliability of the Test

This issue has not yet been discussed by the Courts. However, the following factors detract from the reliability of the test. Firstly, the test is based of the memory of the accused. [29] However, memory is not a passive repository of stored images. [30] It is being constantly recreated and reconstructed. [31] Also, the memory of a crime may be absent due to various reasons. [32] There isn’t enough literature on how memory is formed during a crime. [

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