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Throughout the history of human kind, man has been looking for ways to verify the truthfulness of ones' statements. In 1730, Daniel Defoe suggested 'taking
the pulse' of a suspicious fellow as a practical and more humane method
of identifying a criminal. It was an early suggestion to employ medical
science in the fight against crime. In 1878, Italian physiologist Angelo
Mosso reported experiments in which he observed that the breathing pattern
changed, while blood volume increased due to certain stimuli. His observations
were the result of his studies of emotion, fear and its influence on the
heart and respiration with an instrument called 'plethysmograph'. Mosso
latter devised a 'scientific cradle', which was designed to measure the
flow of blood while a person lay on his back in a prone position, as it
concentrated first on one part of the body and than in other. (Herbold
- Wootten 1982) In 1879, F. Galton developed a much
acclaimed psychological test whereby the subject was presented with a
group of words sufficiently separated in time to allow the subject to
utter his first though generated by each word. For this reason it was
called the word-associated test. The premise of this test is that a guilty
examinee when confronted with a relevant word will suffer from an inner
conflict in his attempt to alter an associated word lacking in culpability.
(Trovillo 1939) In 1895, an Italian criminologist
Cesare Lombroso published the research papers in which he relates his
use of a plethysmograph and sphygmograph (which he developed) during the
interrogation of criminal suspects. Lombroso applied the blood pressure
pulse to actual criminal suspects on several occasions while assisting
the police in the identification of criminals. He developed a device called
hydrosphygmograph, where the suspect's fist would be placed in a water-filled
tank sealed across the top by the rubber membrane. Pulsations of blood
in the fist were transferred to the water and the changes in water level
were carried over into an air-filled tube, which in return recorded the
pulsation on the revolving smoked drum. (Trovillo 1939) In 1892, James Mackenzie, an English
clinician and cardiologist described his 'clinical Polygraph' as an 'ink
Polygraph' with an accurate clock work which drives a paper ribbon with
time markers at one-fifth of a second. (Mackenzie 1908; Reid, Inbau 1977;
Ansley 1992) In 1908, Hugo Munsterberg, a Harvard
psychology professor introduced the forensic application of the word association
technique in detecting deception in the U.S. and further suggested possibilities
in detecting deception through the recording of physiological changes.
(Trovillo 1939); Wootten 1982) In 1913, Vittorio Benussi presented
a paper before the second meeting of the Italian Society for Psychology
in Rome, on the subject of his experiment regarding the respiratory symptoms
of lying. Benussi was possibly the first to employ more than one physiological
measure in the detection of deception by recording heart rate and blood
pressure curve in addition to respiration. (Benussi 1914) In 1915, an American scientist Dr.
William M. Marston devised the systolic blood pressure deception test.
This consisted of intermitted recordings of a suspects' systolic blood
pressure during questioning, using a standard medical blood pressure cuff
and a stethoscope. The cuff required repeated inflation of pressure to
obtain readings at intervals during the examination. During the World
War 1, a committee of psychologists formed by the National Research Council
for the purpose of evaluating the known deception test for possible use
in counter-intelligence investigations determined after a number of experiments
that the systolic blood pressure deception test was superior to other
deception tests and enjoyed 97 percent reliability. As a result, Marston
was recommended for appointment as Special Assistant to the Secretary
of War with authority to employ his technique in counter-intelligence
investigations. It is said that the first use of Polygraph in an espionage
case was conducted by Dr. Marston in 1917-1918. (Ansley 1955) In 1921, psychologist John Larson,
employed by Berkley California Police Department developed an instrument
that continually and simultaneously measured respiration and cardiovascular
changes on a Jacquet Polygraph, which was used extensively in criminal
cases with much success. (Larson 1932, Barland 1988) In 1925, Leonarde Keeler, a Sandford
University psychology major who gained firsthand experience in Polygraph
interrogations from Larson at the Berkley Police Department, developed
an improvement of Larson's apparatus. In 1938, he added a third physiological
measuring component to his Polygraph instrument the Psychogalvanometer,
known as the galvanic skin reflex (GSR). By 1942 Keeler was teaching a
two week Polygraph course for police and military examiners in the USA,
he then expanded it to a six week formal course of instruction in 1948.
(DOD 1984; Barland 1988) In 1938, the FBI uses the Polygraph in espionage investigation for the first time. Special Agent Coffey was the first FBI Polygraphist and probably the first examiner in the (US) Federal Government, who also established the first Federal Polygraph research program. (Ansley & Furgenson 1987; Ansley 1992)
The term Polygraph derives from the Greek words Poly (many) and Graph (writing) - many writings. The name refers to the manner in which selected physiological activities are simultaneously recorded. A Polygraph instrument will collect physiological data from at least three systems in the human body. Convoluted rubber tubes that are placed over the examinees' chest and abdominal area will record respiratory activity. Two small metal plates, attached to the fingers, will record sweat gland activity, and a blood pressure cuff, or similar device will record cardiovascular activity. A typical Polygraph examination will include a period referred to as
a pre-test phase, a chart recording phase and a chart interpretation phase.
The whole examination could take between 2.5 - 3 hours.
The purpose of the pre-test phase is to inform an examinee about the processes and conditions of the Polygraph examination. During the pre-test phase the main issue that will be the subject of a Polygraph examination will be discussed and clarified, and questions may be asked to familiarise the examinee with the testing procedure. In the pre-test phase the Polygraph examiner gathers background information from the examinee and the examinee's version of the event. During this period the examinee will also complete the required paperwork as well as clarify all relevant issues regarding the examination. During the pre-test period all relevant and profile questions are formulated in front of the examinee. Special care is taken to make sure that the examinee understands all the questions, so that there is no opportunity for misunderstandings. The questions are strictly related to the matter of investigation or issue. They should not include personal issues; such as sexual habits or preferences, religious beliefs or opinions regarding racial matters, political beliefs, affiliations and/or financial status, (unless of course the examinee is accused of sexual misconduct). Only after the examinee is fully aware and understands all of the questions
that would be used on the Polygraph examination, and is still willing
to voluntary participate in the examination by signing a consent form,
will the psychophysiologist proceed with the Polygraph testing.
The examinee will be connected to an instrument by two pneumograph tubes, connected around the upper and lower rib cage (measuring breathing pattern), a cardiograph, which consist of a medical blood pressure calf, (measuring cardio vascularity activity), and a two electrodes attached to fingers (measuring sweat gland activity). During this period a minimum of three charts will be recorded from the Polygraph instrument as a result of an examinee's physiological reactions. It could take between 5-7 minutes to record each chart. It is imperative that an examinee sits completely still for that period of a time. Any movement of an examinee's body would be considered as a purposeful attempt of an examinee to disrupt the exam, which in itself is a sign of deception. An examinee would be given two warnings when such behaviour is detected, and after the third warning the test will be cancelled and the result of the test will be"examinee deliberately disruptive".
After collecting Polygraph charts the examiner will analyse them and render an opinion as to the truthfulness of the person taking the test. The Polygraph examiner, when appropriate, will offer the examinee an opportunity to explain physiological responses in relation to one or more questions asked during the test. A final result will be given the same day when appropriate, or sent to the examinee on the next working day in the form of a written report.
A Polygraph test result is a strictly confidential statement and its result can only be disclosed to the examinee or a third party nominated in writing by the examinee. They are four possible results:
It is perfectly normal to assume that examinee is nervous. As a matter of fact a professional Polygraph examiner knows that every examinee is nervous, regardless if the person is guilty or innocent of an accusation. While the guilty person is afraid to be caught, the innocent person is nervous, fearing what if a Polygraph examiner is not professional enough to prove his/her innocence.
Termination of a Polygraph Examination At any time or phase of the Polygraph examination an examinee can terminate the test, by telling the examiner that he/she does not want to continue with the test. In this case the fees payable for the test are not refundable.
Global Polygraph is using the latest available computer technology in the hands of qualified Polygraph examiner (Forensic Psychophysiologist) to determine the truthfulness of a person's statement(s).
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