This presentation is all about polygraph machine, polygraph test and EEG machine

1. Dayalbagh Educational institute
CGM403 SEMINAR
Submitted by- Poorva Nazkani
-Purvi Chandani
- Chanchal Dhakad

2. TOPIC - Polygraph Machine Based Study

3. Introduction
A polygraph often called a lie detector , is a machine that measures
human responses to questions , measuring a lot of physiological
symptoms of anxiety or emotion to estimate if the subject is being
truthful or not. It is a device or a procedure that measures and records
several physiological indicators such as blood pressure, pulse ,
respiration and skin conductivity while a person is ask and answers a
series of questions. A polygraph test is used to prove truthfulness of a
subject and measure and records of several physiological indices.

4. History
The study of physiological methods for deception test measuring emotional
disturbances begin in the early 19th century. Benussi was the first to work on
practical deception test based on physiological changes.And the first attempts
to develop a scientific instrument to detect Ruth was made by Lombroso in
1895. Later, Larsen and Keelar independently designed instruments with new
features to make it more versatile. Finally, John Augustus Larson invented the
Polygraph Machine in 1921 AD .

5. Objectives of Polygraph Test
• To verify the veracity of the statement of suspect, witness and complainant
in all types of crime.
• To replace the third degree method of interrogation in a scientific manner.
• To examine white collar criminals, economic offenders, cyber criminals and
other offenders.
• To corroborate or to refutes the findings of the investigation.

6. Who should not take Polygraph Test
• Person with serious heart condition
• pregnant women
• Mentally incompetence
• Nerve damage or paralysis
• Any person who has stroke or is an epileptic ( a person who is in pain,
headache, toothache)

7. For Polygraph Test
• Good night sleep
• Don’t consume alcoholic beverage
• Don’t use illegal drugs for 24 hours prior to examination.
• Injury illness or physical condition that can impact you

8. Uses of Polygraph
When most people think of polygraphs, they think of Lie detector test solely used
for prosecution processes. However this is not always the case.there are various
reasons why someone may utilise a polygraph test and its not always a bad thing.
Some uses of polygraph test are-
1. Pre-emoployment Screening
A pre-employment screen is one of the most common utilisations of a polygraph
test.Potential employers who are serious about hiring a trustworthy the employee
may require candidates to perform polygraph tests to prevent any potential
liabilities to the company.

9. • Infidelity
Although infidelity is not a crime, it’s still a serious matter.significant others who are skeptical
of their partners royality may require he or she take a polygraph test.
• Wrongly Accused
Those who are wrongly accused of a behaviour or actions may opt to take a polygraph test to
prove their honesty
• Monetary Or Bank trust
This will occur when bank account holders fall into a large amount of money. When this
occurs, a bank will often times required a polygraph test to assure the funds came from a
legitimate source.
• Helps in criminal investigations
By the use of Polygraphs, criminal investigations have been done. Suspect is asked to take a
polygraph test and polygraph test also verify a crime has occurred or not.

10. POLYGRAPH INSTRUMENT
Principle
The polygraph is based on the principle of psychosomatic interaction of an
individual. This means , a change takes place in person who consciously holds
feelings, which manifest into physiological changes in his blood pressure, pulse
rate, respiration and electrodermal response. Hence it is the fear of the texans
and not the guilt which produces measurable physiological responses.

11. Instrumentation
The instrument typically used to conduct polygraph tests consists of a
physiological recorder that assesses three indicators of autonomic arousal:
heart rate/ blood pressure, respiration, and skin conductivity. Most
examiners today use computerized recording systems. Rate and depth of
respiration are measured by pneumographs wrapped around a subject's
chest .
Cardiovascular activity is assessed by a blood pressure cuff.skin conductivity
( called the galvanic skin or electrodermal response)
is measured through electrodes attached to a subject's fingertips.

13. The physiological channels that the polygraph measures have remained largely
unchanged from Keeler’s original models (Buckley, 1980). They are
cardiovascular activity (red line, Figure 1), respiratory activity (blue line, Figure
1) and electrodermal activity (green line, Figure 1) which is also known as GSR.
Increases in heart rate and blood pressure are brought on by the sympathetic
nervous system releasing the postganglionic neurotransmitter norepinephrine,
while a decrease in heart rate and blood pressure is brought on by the
parasympathetic nervous system releasing postganglionic acetylcholine.
Pressure-sensitive receptors, baroreceptors, play a central role in activating the
appropriate system when blood pressure suddenly drops or rises, thus
maintaining the basal blood pressure required for sustained life (Berntson,
Cacioppo, & Quigley, 1991). Cardiovascular activity is, however, modulated by a
range of other factors beyond this basic mechanism.

14. Perceived threats, increased physical or mental activity, the anticipation of a threat or
activity, and effectively any form of specific or general arousal can affect heart rate, blood
pressure and other cardiovascular processes in a range of waysThey can differ subtly or
radically amongst individuals (especially for those with active mental illnesses or anxiety
disorders) and even for the same individual under different circumstances. This has obvious
implications for polygraph practitioners, who employ techniques that assume certain
patterns of cardiovascular activity to be characteristic of certain psychological states (e.g.
deceptiveness) across individuals and situations.
Respiratory activity is even more problematic in this regard as it is affected by both the
autonomic and the central nervous system. In the autonomic nervous system, breath
intakes are initiated in the medulla and pons by the spontaneous firing of neurons, and
then modified based on carbon dioxide and oxygen concentrations in the blood, as
respectively detected by central and peripheral chemoreceptors, while stretch receptors
monitoring lung inflation modulate respiration further.

15. The central nervous system allows an individual to easily bring respiratory activity under
voluntary control, which represents a problem for polygraph examiners due to the fact
that both heart rate and GSR can be affected by changes in breathing, e.g. a sharp intake
of breath reliably produces an electrodermal response (EDRs) due to respiratory sinus
arrhythmia.
Electrodermal activity has long been regarded the most sensitive and reliable of the three
channels of the polygraph.The electrical resistance and conductance of the skin is largely
determined by the activity of the sweat-producing eccirine glands, which are controlled by
the sympathetic nervous system. However, due to eccirine glands having acetylcholine as
their postganglionic neurotransmitter, they are not affected by epinephrine (commonly
known as adrenaline) or norepinephrine level fluctuations in the blood, like cardiovascular
and respiratory activity . While this does make the GSR channel less prone to being
affected by extraneous factors, it in no way eliminates the inherent problems associated
with any attempt to infer psychological states based on peripheral nervous system activity.

17. REFERENCES
• S.2000 Polygraph testing and the DOE national
laboratories.science.
• 1973 Polygraph Examiner's training model.mew York:
backster school of lie detection.

18. THANK YOU