The polygraph, also known as a lie detector test, measures physiological indicators such as blood pressure, pulse, respiration, and skin conductivity to determine whether a person is lying. It was developed in the early 20th century based on the theory that physiological responses differ when a person is being deceptive versus telling the truth. The test involves attaching sensors to the subject and asking them a series of questions while recording their physiological signals. An examiner then interprets the signals to assess whether the subject's responses are consistent with lying. However, the reliability of polygraph tests remains controversial.

1. “The guardian of truth in a world of uncertainty.”
POLYGRAPH
Name- Adrita Dam
Subject- Forensic Psychology and Criminal
Psychology

2. Topics:
Introduction
History
Principle
Methodology and Parts of Polygraph
Procedure of Interrogation
Subject’s Rights
Legal Status in India
Reference

3. Introductio
n
• Polygraph is derived from the two Greek terms. "Poly" means "several" and "graphos" means "write".
Thus, the term polygraph is used to create graphs using many physiological parameters such as blood
pressure, respiration, pulse rate, skin conductance, etc. means to ask.
• Physiological deception detection is the cornerstone of lie detector testing. It is believed that people
have different physiological responses to lying than to telling the truth. For example, lying down can
increase your heart rate and make your palms sweaty. By measuring these physiological responses,
polygraph examiners can determine whether a person is being honest. However, it is crucial to note that
the reliability of polygraph testing remains a much debated and controversial topic.

4. HISTORY
OF POLYGRAPH

5. CESARE LOMBROSO
A device known as “Hydro-sphygmograph” (which is an
obsolete kind of sphygmograph) built by Cesare Lombroso in
1895 to record changes in blood pressure during interrogation
ushered in the invention of the polygraph. This ideology was
not that effective, but it gave an idea of ​​how one could utilize
the mechanics other than engaging in such inhumane acts.
5

6. Vittorio Benussi
• 1902 - Medical student Vittorio Benussi developed a
device that measures the changes in a person's blood
pressure and breathing and thought to be used to
deceptively detect those changes. However, it was not
considered for use.

7. WilliamMarston
1915 - William Marston, an American psychologist at
Harvard University, develops a prototype of the modern
polygraph. The device can measure changes in blood
pressure, pulse rate, respiration, etc., providing an
opportunity to see changes in the event of a false
statement. He called himself the "father of the polygraph".
In 1938 he authored a book entitled "THE LIE
DETECTOR TEST" which explained the theory and use
of this device. Gillette Company Pvt. applied in 1938. The
corporation claimed that a "polygraph" showed its razor
blades to be superior to others on the market.

8. • 1921 - Ph.D. John Augustus Larson was a
physiology graduate student of the University of
California in 1920. He was also the first American
police officer to receive a doctorate. He worked as
a police inspector in Berkeley, California, USA. He
is best known for discovering the modern
polygraph used in forensic psychological deception
detection in 1921, known as "Berkeley’s
Psychograph". His device was equipped with
mechanisms to record both blood pressure as well
as galvanic skin response. Invented in 1939 to be
portable, it became even more convenient as it
could be carried anywhere in case of emergency
interrogation.
John Augustus Larson

9. The instrument was then purchased by the Federal Bureau of
Investigation and served as a prototype for the latest in
polygraph measurement technology.

10. Darrow Behaviour Research Photo-Polygraph B. Keeler polygraph Berkeley polygraph
A variety of similar devices have been designed, including: B. Keeler polygraph developed in
1936.
The Lee’s was a version of the original Berkeley polygraph that incorporated his psychograph
device, blood pressure and respiratory recorder. The other was the Darrow Behaviour
Research Photo-Polygraph, designed by John E. Reed in 1945, which claimed that the device
could record changes in muscle activity, such as changes in blood pressure. Although the
device was for research purposes only, it claimed to be more accurate in detecting deception
because it used standardized recordings of pressure, pulse, and respiration and made these
recordings continuously.

11. Principle:
A polygraph is based on the principle of changes in physiological responses that
indicate whether a person is telling the truth or deceiving. A polygraph machine
measures and documents various physiological parameters such as blood
pressure (BP), pulse, respiration and skin conductivity while asking a series of
questions to the patient. The main operating principle is based on the assumption
that people are lying about the level of stress they experience leading to changes
in physiological responses. These changes are detected by a polygraph and
interpreted by an expert to determine the level of deception. However, it is
important to note that the accuracy and reliability of this test has been the
subject of reasonable controversy and debate in the scientific community and
courts. In some studies, the device gave false positives to people who were
nervous during interrogation, and to experienced and latent liars who could
easily fool the test and its basic mechanics. It has been shown to give false
negatives. As such, polygraph results are still not very well received in many
jurisdictions.

12. Methodology:
 First, the person is seated in a chair, then the instrument
parts are correctly affixed to the various parts of the body.
 Next, put the arm cuff on your arm to record your heart
rate and blood pressure.
 Place an elastic band on the chest and measure arterial
and respiratory amplitudes and deviations.
 To do this, place the electrode lead on the first phalange
of the index finger to record the galvanic skin response.
 The response is then recorded graphically on paper and
the statistics of the various undesirable reactions are
examined along with the strength of the reaction, the time
and degree of excitation of the reaction.
 The examiner then asks a series of questions and the
device records the subject's physiological responses.
 The charter then displays the data on paper in the form
of a chart, and the examiner interprets the results to
determine whether the person is truthful or deceptive.

13. Pneumograph
Galvanograph
Cardio-vascular Recorder
Chart recorder
Parts:
1. Respirometer/Pneumograph: This measures a person's breathing pattern. Two
rubber tubes are then wrapped around the subject's chest and abdomen to record
the movements of the chest and abdomen during breathing.
2. Galvanograph: This measures the conductivity of human skin. This can
increase when a person is stressed or anxious. Two electrodes are attached to the
subject's finger or palm to measure skin conductance.
3. Cardiovascular recorder: This records a subject’s heart rate as well as blood
pressure. Two blood pressure cuffs are positioned around the subject's arm and a
pulse sensor is placed on the finger or wrist to record changes in heart rate.
4. Chart Recorder: Records data collected by respirometers, galvanometers, and
cardiovascular recorders on moving paper charts.
Sl. No. Instrument Name Part of the Body
Attached to
Purpose for attachment
01 Pneumograph Chest area To measure the respiratory changes
02 Sphygomography Upper arm To measure the cardio-vascular
changes
03 Transducer
(or plethysmograpgy)
Thumb To measure the blood volume
reflecting the pulse rate
04 Galvanograph Fingers of palm To measure the conductivity of
human skin

14. PROCEDURE OF INTERROGATION:
 One must be ready to take the test without medication
beforehand.
 The preparation of the mind for the exam has to be
administered, since certain individuals are completely
unsuitable for this test like individuals with manic
identities, overly receptive identities, and addictions.
Those who suffer from mesh anomalies who fall into one
of these three conditions, and those who are naturally
grumpy, enthusiastic and uncooperative. These subjects
require unusual preparation and take longer to take the
exam. Not suitable for prepared exams.

16. Alignment of topics (for those suitable for
prepared exams):
The patient undergoes a preliminary examination, which
should clarify the reasons, purposes and methods of the
polygraph examination according to the patient's ideal
understanding. To get meaningful test results, the analyser
needs to have information about the events. Subjects must be
told that they will be asked a specific question and that the
question must be answered "yes" or "no“, because these
questions are thought-provoking. Subjects do not have to
worry about misrepresentation or translation of the
polygraphic test. But if he misdirects after that, it will be
indicated in the test. At the time of organizing, you should be
familiar with the question and understand it well enough to
be able to answer yes or no. In an ideal interrogation, one
shouldn't be asked more than 10 questions in the same
session.

17. First, three types of questions to be
asked:
 Irrelevant question:
These are certain questions unrelated to
crime frequency. For example – “are you
Mr. X? Are you 28 already? Are you a Y
class resident? Do you work for company
Z?”

18.  Related questions:
It’s purpose is usually to implicate the
suspect in a crime or to point out that the
interviewer has information about some
aspect of the crime. "On November 10, 2012
at 5:00 pm, you injured Mr. A at your home,
or you witnessed Mr. B hurt Mr. A on
November 10, 2012 at 5:00 pm, from the
bank 5,00,000 rupees was stolen. The answer
to any key question should be 'yes' or 'no'.

19. Control questions:
A control address is necessary to adequately understand and explain the practical phrases inscribed in the
subject's responses and mental responses to various compelling questions, but this is largely generalized in
nature, related to some small terrifying deeds that the person may commit. Precious moments of his childhood
should not be neglected. Examples: "When you were a kid, did you ever steal money out of your mother's pocket
to buy gaming supplies?" "Have you ever considered robbing a bank or other similar means to obtain cash ?”
The charming reply reflected a hostile reaction which reflects a meaningful representations of physical ability in
different ways.
Non-essential questions are asked to encourage a comparison of responses to amended responses and ambiguous
responses. A distinction that can be made by interpreting responses to controlled questions to evaluate whether a
person is responding to questions that suggest that the person may be indirectly involved in an act in which he or
she did not commit can be done. Therefore, control questions with equally aberrant answers or negative answers
count as the person's negative, nervous, or other systemic reaction to the relevant question or problem

20.  Proper examination:
The individual to be inspected is made
to sit on a polygraph chair in such a
way that he faces the instrument and
the administrator faces him so that he
can watch the facial responses of the
subject.
Questions should be organized so that practical
answers are easily comparable and self-
explanatory. All of this must be done in such a
way that, after making a misleading response to
one important address, so that one can revert to
their usual method of responding to prepare for
another important address.

21. SUBJECT RIGHTS:
Critics of polygraph technology point out that the
technology is an invasion of the subject's privacy. To
counteract this disparagement, certain rights of subjects have
been constructed. These rights are respected. Examination of
subjects may only be performed by qualified inspectors. The
person must be found suitable for polygraph examination; the
subject must be well aware of the reason for the polygraph
examination. The subject must know how a polygraph
examination is performed; and must agree for the Lie
Detector Test. The subject can refuse to take a lie detector
test. Individuals’ must not be subjected to mental or physical
violence; and must not be subject to extensive interrogation.

22. Legal Status of Polygraphin India:
The use of polygraph testing, also known as polygraph
testing, is inadmissible as evidence in Indian courts. The
Indian Evidence Act of 1872 does not recognize the
results of polygraph examinations admissible.
Although, Polygraph is not admissible there are certain
Cases where it has been used:
 Aarushi-Hemraj double murder case
 Nithari serial killings
 Jessica Lal murder case
 Sheena Bora murder case

23. Reference:
1. Journal of Bio Innovation. (n.d.). https://www.jbino.com/
2. W3admin. (2019). What is polygraph. Vollmer Institute. https://vollmerinstitute.com/what-is-polygraph/
3. SCIENTIFIC AND LEGAL PROCEDURE OF POLYGRAPH TEST - PDF Free Download. (n.d.).
http://docplayer.net/25090010-Scientific-and-legal-procedure-of-polygraph-test.html
4. https://doku.pub/documents/nandys-principles-of-forensic-medicine-3rd-editionpdf-7l51g2ny770k
5. https://www.youtube.com/watch?v=xCQomMCOdmw