2. The polygraph technique uses the principle that the
body functions of a person are influenced by his mental
state. The physiological changes accompanying
deception are capable of being recorded, measured and
interpreted with reasonable certainty. Base on my
understanding, many observable signs have been linked
to lying, but they are not always shown by everyone. The
absence of these signals does not mean a person is
honest, but their presence, especially when there are
multiple signs, is very suggestive of potential deceit.
When lying, the face often shows messages and that is
what the liar wants to show and what the liar wants to
conceal. Some person who is lying shows Involuntary
facial expression revealing true emotion.
I. PSYCHOLOGY OF THE LYING PERSON
3. Telling a lie is usually an emotional experience causes the mind of the examinee, which produces an emotion of fear or
anxiety, manifested by fluctuations in pulse rate, blood pressure, breathing and perspiration. Knowing that dishonesty
risks irrevocable damage to one’s reputation, lying is an inherently stressful activity. When we engage in deceit, our
respiratory and heart rates increase, we start to sweat, our mouth goes dry, and our voice can shake. Some of these
physiological effects form the basis of the polygraph examination.
Here, I outlined and shortened form the related topics that I understood connected to our system:
The Central Nervous System (CNS) – is composed of the brain and the spinal cord. All other nerve ways are within the
peripheral nervous system which separates into two: The Somatic Nervous System and the Autonomic Nervous System.
1. Somatic Nervous System – is involved with voluntary comparative over skeletal muscles.
2. Autonomic Nervous System – involved those involuntary physiological functions of the body and has considerable
psychological impact as well.
TWO DIVISIONS OF AUTONOMIC NERVOUS SYSTEM
1. Parasympathetic Nervous System (PNS) – the housekeeping or braking system. It is responsible for conserving energy
and making sure necessary bodily functions.
-restrains sympathetic arousal and attempt to maintain homeostatic(homeostasis)normal.
2. Sympathetic Nervous System (SNS) – is our emergency, or action system.
-a system which causes the sudden and dramatic change.
4.
5. In my own understanding, when the subject of the examination fears being discovered,
this fear results in a detectable physiological response when the subject acts deceitfully.
Thus, in this theory, the polygraph instrument is measuring the fear of detection rather
than deception per se. And the examiner infers deception when the physiological
response to questions about the crime or unauthorized activity is greater than the
response to other questions. However, the examinee’s intelligence level, state of
psychological health, emotional stability, and belief in the “machine" are among the
several other factors that may, at least theoretically, affect physiological responses.
A stronger theoretical base is needed for the entire range of polygraph applications.
Basic polygraph research should consider the latest research from the fields of
psychology, physiology, psychiatry, neuroscience, and medicine; comparison among
question techniques; and measures of physiological response.
THEORY OF POLYGRAPH EXAMINATION
6. TRIPOD FOUNDATION OF POLYGRAPHY
1. Psychological Leg Premise – states that specific nervous
system component whose stimulation can thus be
diagnosed are so stimulated by the involuntary and
emotional processes of the individual who is continuously
attempting concealment of deception especially if that
individual has something at stake and the prevailing
circumstances lead him to believe that exposure to
deception is quite possible although undesirable.
2. Physiological Leg Premise – among the physiological changes
that may be recorded and identified are those that
automatically occur only following the stimulation of specific
nervous system component and from which stimulation of
those specific nervous system components can be reliably
diagnosed.
3. Mechanical Leg Premise – polygraph is capable of making
graphic record containing reliable information regarding
physiological responses of the subject.
7. GENERAL PURPOSES OF USING POLYGRAPH
1. Security Risk- Leakage of Information, Intelligence and Counter-Intelligence The use of polygraph testing
for preemployment screening is even more complicated because it involves inferences about future
behavior on the basis of information about past behaviors that may be quite different, for example of types
of questions is: does past use of illegal drugs, or lying about such use on a polygraph test, predict future
spying?
2. Criminal Law Infraction- Murder, Robbery, Theft, Rape etc.
3. Personnel Screening
4. Misconduct
5. Medical Measurements
