Polygraph test in law
The polygraph test also known as the lie detector test is such a test or an activity
that is undertaken to find the truth and is basically experimented on the
accused, suspect, or witness when they are asked to tell the truth at times asked
by the examiner. By undergoing this test a person gets easily caught if he or she
tries to hide things and tell lie. They are also called a Deception Detection test
And they have a wide moral, legal, and social importance in society. These tests
like polygraph test, narco analysis, brain mapping, live detector test are some of
the tests which help in the investigation of a crime. By conducting the
investigators' police, lawyers easily detect the lies from the culprits. And
also increase the efficiency in the inquisition or inquiry of the crime. So from this
article, we are going to know more about the polygraph test in detail, Its
advantages and drawbacks, the methods to conduct, whether it is violative of the
fundamental rights of the accused.
First, we need to understand the method of conducting the polygraph test
in order to know whether this test can be reliable or not.
METHOD OF THE TEST:-
The theory which follows this test is that when a person is telling a lie or is lying
about something then his body will produce different physiological responses or
effects such as increased heart rate, blood pressure, respiratory rate, skin
conductance which is more than the normal course. And it will be noted by the
examiner while conducting the test. And there will be an instrument called
electromyography which will record the electrical activity of different parts of the
The examiner begins the test with a pre-interview session to gain some
information beforehand which can be used later on for diagnosing questions.
And then the examiner will make that person undergoing the test explain how it works and it is very important to speak the truth. Then after that, a small demo test is conducted to test whether it can detect the lie so that the person can be sure that the test can detect the lie. Then the real test start by which the examiner asks certain irreverent questions then others are diagnostic questions. And the examiner actually tests in asking the relevant questions. The different types of questions alternate and then the test is passed if the physiological responses to the diagnostic questions are larger than those of the irrelevant
Then next comes the control question technique(QCT). The examiner before
conducting this technique have informed the person regarding the validity of the
administration of the control question technique. It starts with some interrogative
questions by which it elicits a nervous response from the suspects.
An alternative to this technique is the guilty knowledge test or the concealed
information test. The examiner conducts this test with having no knowledge of
the crime . The examiner tests the suspect on the knowledge of the crime that is
not known to the innocent person. The questions are multiple questionsbased and
the participants are rated on how they react to the correct answer.
WHO ALL CAN TAKE THE POLYGRAPH TEST?
The National Human rights commission adopted certain guidelines on 12th
November relating to the administration of the Polygraph or Lie detector test as
the commission received many complaints against the test that it is being
conducted by coercion or without the consent of that person. So the commission
decided as the lie detector test is not regulated by law so they formulated certainly
guidelines thathas need to be followed. The following guidelines are:-
1) No test can be conducted without the permission of the accused. Options
should be provided to the accused to ask whether they want to undertake the
test or not and if they agree to do it voluntarily then he should be given access to
the lawyer and then the police and the lawyer should make the accused
understand the legal, physical and emotional aspects of such a test to him.
2) The consent given by the accused should be recorded before a judicial
3) During the hearing before the judge the accused should be represented by a
4) The judge or magistrate should take into consideration all the factors relating
to the length of the detention and nature of the interrogation.
5) The real recording of the accused should be done in an independent agency
such as hospital and presented in presence of a lawyer.
1) The investigating officer has to send a requisition addressed to the director, state FSL to request them to give a date for the polygraph examination. The requisition has to be forwarded by the superintendent of police or sub-divisional police officer. While sending requisition the officer has to attach all necessary documents such as FIR, statements of subjects recorded under section 161 CrPC, briefcase history, and if there is any photograph. This will make the experts understand the nature of the crime, and where, how and
when the crime was committed.
2) The investigating officer is advised to requisition of the services of polygraph division only after making a further inquiry and collecting relevant documents such as mobile call details, PM report, inquiry reports, age certificates.
3) The laboratory will communicate the date for consultation with the investigating officer. The experts after checking the facts will prepare a questionnaire and then fix the date for the polygraph test.
4) THe investigating officer has to meet the concerned expert at state FSL, for
discussion and for conducting the examination.
5) Before sending the requisition the investigating officer has to attach a
a eclaration that he has taken the consent of the subjects under article 20(3) of
the constitution as passed by the orders of the supreme court.
6) Only the list nominated will be examined on that date and time fixed by the
7) In the case of women undergoing the test a women constable is required to
accompany the suspect who will remain present during the examination.
8) All the minor accused will be accompanied by their parents /guardians
compulsory who will sign the consent form.
BENEFITS OF POLYGRAPH TESTING:-
Polygraph testing has great significance as they have several practical applications. These tests are specifically conducted to detect the truth fullness from the accused committing a crime. They are used in crime investigation, security agency, business fields, and other organized sectors.
It is one of the major fields in which polygraph testing is conducted to detect
crime. They offer government agencies and legal systems a very useful way to
detect crimes from the accused. Crime investigation teams afford more
complex procedures and they do more interrogation to find out the truth. They
also apply disciplinary methods to detect the truth. So therefore polygraph testing
is very valuable and important in crime investigation fields because it helps them
to ascertain the truth.
The polygraph test is also very important in security agencies as it helps the security
agencies to identify the suspected terrorists and other criminals who try to hide their identity. Polygraph testing not just only help in suspecting the criminal but also provides justice to the innocent victims in the crime who are punished in the court due to the wrong verdict. The polygraph test is very effective in crime investigation. It also does not deal with any physical pain on the crime suspects.
Industry and business sectors:-
In industries, they contribute towards enhancing effective organization. Their job
is to select candidates on the basis of their skills and experience and also promoting them honestly in the organization. But there are some candidates who in job recruitment do not provide correct information and might dishonestly possess their skills for getting selected. So in such cases, a polygraph test is very useful and it helps in detecting the truth. Another application is a polygraph test that helps in discovering employee thefts in the organization. Although there are so many organizations that try to employ their own methods of questioning the suspect thathelps still will not give correct results so the most relevant method of conducting the test is polygraph testing.
The traditional methods of gathering evidence may not always give many correct or
desired information. In some cases, the police officers use violence to extract
information from the criminals but that is not the correct way as it harms the
body of the accused, and also the accused may confess in the fear of violence
without having committed the crime. So in these situations the police officers can
use various scientific methods like polygraph test, narco analysis , brain mapping
in extracting the information and without doing any physical violence.
Disadvantages and negative impact
It may be illegal- under federal law, it states that an employer cannot use a
polygraph test until and unless there is a current investigation into an actual loss.
Only certain types of employers are allowed to undergo such tests. These include
pharmaceutical manufacturers, security service organization. When a ,polygraph
test is conducted it has to follow certain strict standards . Under this act the
information obtained during the polygraph test is strictly confidential.
According to an American psychological assosciation, Polygraph test may produce
mixed results. It is still vulnerable to both physical and psychological countermeasures and also produces insignificant errors based upon false-negative results.
The results might not be accurate. The examination procedure for conducting a lie detector test is very lengthy and requires a subject to remain still. The lack of accuracy in these instruments is reflected in the misclassification of test subjects.
Polygraph testing tends to produce many ethical problems. Polygraph testing is
clear occupation into the personal privacy and liberties of an individual as many
accused or criminals are forced to undergo the test. In the case of industrial thefts
several workers are subjected to undergo this test which is against their wish is an
an important challenge to their personal autonomy.
Secondly explaining the results is another source of ethical violation in polygraph
testing. Since there is no relationship which is established between the
physiological responses and dishonest behavior.The test administrators interpret the results in a very biased manner without giving accurate results
which is itself unethical and unfair.
The legality of polygraph testing:-
The constitution protects the right of an individual from self-incrimination and
privacy and from unlawful search and activities. The constitution provides for a
general right to privacy and protects these rights against violation of privacy. It
has been argued in the jurisdictions that the right to privacy is surrendered or given out
when the employer can demonstrate a sufficient interest so it has been also argued that when an employer gives his permission for the polygraph testing he gives up his right to Polprivacy. Where conducting the polygraph test is voluntary there cannot be interference of privacy. The consent given by the person undergoing the test must be in writing and the person need to be informed that the testing is voluntary. There are certain condition such as only questions discussed prior to the examination has to be used and he or she has the right to be presented by an interpreter. There cannot be discrimination of threats.
Polygraph tests are conducted for detecting whether a person is lying or not. The
act of telling a lie is reflected from the person’s physiological and neurological
responses as their behavior changes if they deliberately try to hide the truth.
Polygraph test has many applications in different fields. It is a very scientific way
to detect the crime without causing any physical harm to the criminals.
Application of polygraph test is very much significant in crime investigation,
national security , employee theft. The success of polygraph testing will depend
on the ability to minimize misclassification of subjects. Sometimes there is a
problem where it declares false results which make the innocent as guilty .
The polygraph or lie detector test is a better method than the conventional method of
interrogation because in a conventional method the accused has to go through long
hours of interrogation and the policemen apply physical pressure on the accused
to confess their crimes whereas a polygraph testing is a very efficient method of
detecting a lie.