Polygraph
From Wikipedia, the free encyclopedia
A polygraph (popularly referred to as a lie detector) is an instrument that
measures and records several physiological indices such as blood pressure,
pulse, respiration, and skin conductivity while the subject is asked and
answers a series of questions, in the belief that deceptive answers will
produce physiological responses that can be differentiated from those
associated with non-deceptive answers.
Polygraphy is widely rejected as being pseudoscience by the scientific
community.[1] Nonetheless, polygraphs are in some countries used as an
interrogation tool with criminal suspects or candidates for sensitive public or
private sector employment. US federal government agencies such as the
FBI and the CIA and many police departments such as the LAPD use
polygraph examinations to interrogate suspects and screen new employees.
Within the US federal government, a polygraph examination is also referred
to as a psychophysiological detection of deception (PDD) examination.
History
The idea that lying produces physical side-effects has long been claimed. In
West Africa persons suspected of a crime were made to pass a ostrich's egg
to one another.[citation needed] If a person broke the egg, then he or she
was considered guilty, based on the idea that their nervousness was to
blame. In ancient China the suspect held a handful of rice in his or her
mouth during a prosecutor's speech.[citation needed] Because salivation
was believed to cease at times of emotional anxiety, the person was
considered guilty if by the end of that speech the rice was dry.
Early devices for lie detection include an 1885 invention of Cesare
Lombroso used to measure changes in blood pressure for police cases, a
1904 device by Vittorio Benussi used to measure breathing, and an
abandoned project by American William Marston which used blood pressure
and galvanic skin response to examine German prisoners of war (POWs).[2]
Marston wrote a second paper on the concept in 1915, when finishing his
undergraduate studies. He entered Harvard Law School and graduated in
1918, re-publishing his earlier work in 1917.[3] According to their son,
Marston's wife, Elizabeth Holloway Marston, was also involved in the
development of the systolic blood pressure test: "According to Marston’s
son, it was his mother Elizabeth, Marston’s wife, who suggested to him that
'When she got mad or excited, her blood pressure seemed to climb' (Lamb,
2001). Although Elizabeth is not listed as Marston’s collaborator in his early
work, Lamb, Matte (1996), and others refer directly and indirectly to
Elizabeth’s work on her husband’s deception research. She also appears in
a picture taken in his polygraph laboratory in the 1920s (reproduced in
Marston, 1938)."[4][5] The comic book character, Wonder Woman, by
William Marston (and influenced by Elizabeth Marston[6][7]) carries a magic
lasso which was modelled upon the pneumograph (breathing monitor) test.[6]
[8]
Marston was the self-proclaimed “father of the polygraph” despite his
predecessor's contributions. Marston remained the device's primary
advocate, lobbying for its use in the courts. In 1938 he published a book,
The Lie Detector Test, wherein he documented the theory and use of the
device.[9] In 1938 he appeared in advertising by the Gillette company
claiming that the polygraph showed Gillette razors were better than the
competition.[10][11][12]
A device recording both blood pressure and galvanic skin response was
invented in 1921 by Dr. John A. Larson of the University of California and
first applied in law enforcement work by the Berkeley Police Department
under its nationally renowned police chief August Vollmer. Further work on
this device was done by Leonarde Keeler.[13]
Several devices similar to Keeler's polygraph version included the Berkeley
Psychograph, a blood pressure-pulse-respiration recorder developed by C.
D. Lee in 1936[14] and the Darrow Behavior Research Photopolygraph,
which was developed and intended solely for behavior research experiments.
[14][15]
A device which recorded muscular activity accompanying changes in blood
pressure was developed in 1945 by John E. Reid, who claimed that greater
accuracy could be obtained by making these recordings simultaneously with
standard blood pressure-pulse-respiration recordings.[14][16]
[edit] Testing procedure
Globe icon.
The examples and perspective in this section may not represent a
worldwide view of the subject. Please improve this article and discuss the
issue on the talk page. (April 2010)
Today, polygraph examiners use two types of instrumentation: analog and
computerized. In the United States, most examiners now use computerized
instrumentation.[citation needed]
A typical polygraph test starts with a pre-test interview to gain some
preliminary information which will later be used for "control questions", or
CQ. Then the tester will explain how the polygraph is supposed to work,
emphasizing that it can detect lies and that it is important to answer
truthfully. Then a "stim test" is often conducted: the subject is asked to
deliberately lie and then the tester reports that he was able to detect this lie.
Then the actual test starts. Some of the questions asked are "irrelevant" or
IR ("Is your name Chris?"), others are "probable-lie" control questions that
most people will lie about ("Have you ever stolen money?") and the
remainder are the "relevant questions", or RQ, that the tester is really
interested in. The different types of questions alternate. The test is passed if
the physiological responses during the probable-lie control questions (CQ)
are larger than those during the relevant questions (RQ). If this is not the
case, the tester attempts to elicit admissions during a post-test interview, for
example, "Your situation will only get worse if we don't clear this up".[17][18]
Criticisms have been given regarding the validity of the administration of the
Comparative Questions test (CQT). The CQT may be vulnerable to being
conducted in an interrogation-like fashion. This kind of interrogation style
would elicit a nervous response from innocent and guilty suspects alike.
There are several other ways of administrating the questions.
An alternative is the Guilty Knowledge Test (GKT), or the Concealed
Information Test (CIT). The administration of this test is given to prevent
potential errors that may arise from the questioning style. The test is usually
conducted by a tester with no knowledge of the crime or circumstances in
question. The administrator tests the participant on their knowledge of the
crime that would not be known to an innocent person. For example: "Was
the crime committed with a .45 or a 9 mm?" The questions are in multiple
choice and the participant is rated on how they react to the correct answer.
If they react strongly to the guilty information, then proponents of the test
believe that it is likely that they know facts relevant to the case. This
administration is considered more valid by supporters of the test because it
contains many safeguards to avoid the risk of the administrator influencing
the results.[19]
[edit] Validity
Polygraphy has little credibility among scientists.[20][21] Despite claims of
90-95% validity by polygraph advocates, and 95-100% by businesses
providing polygraph services,[22] critics maintain that rather than a "test",
the method amounts to an inherently unstandardizable interrogation
technique whose accuracy cannot be established. A 1997 survey of 421
psychologists estimated the test's average accuracy at about 61%, a little
better than chance.[23] Critics also argue that even given high estimates of
the polygraph's accuracy a significant number of subjects (e.g. 10% given a
90% accuracy) will appear to be lying, and would unfairly suffer the
consequences of "failing" the polygraph. In the 1998 Supreme Court case,
United States v. Scheffer, the majority stated that "There is simply no
consensus that polygraph evidence is reliable" and "Unlike other expert
witnesses who testify about factual matters outside the jurors' knowledge,
such as the analysis of fingerprints, ballistics, or DNA found at a crime
scene, a polygraph expert can supply the jury only with another opinion..."
[24] Also, in 2005 the 11th Circuit Court of Appeals stated that “polygraphy
did not enjoy general acceptance from the scientific community”.[25] Charles
Honts, a psychology professor at Boise State University, states that
polygraph interrogations give a high rate of false positives on innocent
people.[26] In 2001 William G. Iacono, Distinguished McKnight University
Professor of Psychology and Neuroscience and Director, Clinical Science
and Psychopathology Research Training Program at the University of
Minnesota, published a paper titled “Forensic “Lie Detection": Procedures
Without Scientific Basis” in the peer reviewed Journal of Forensic
Psychology Practice. He concluded that
Although the CQT [Control Question Test] may be useful as an investigative
aid and tool to induce confessions, it does not pass muster as a scientifically
credible test. CQT theory is based on naive, implausible assumptions
indicating (a) that it is biased against innocent individuals and (b) that it can
be beaten simply by artificially augmenting responses to control questions.
Although it is not possible to adequately assess the error rate of the CQT,
both of these conclusions are supported by published research findings in
the best social science journals (Honts et al., 1994; Horvath, 1977;
Kleinmuntz & Szucko, 1984; Patrick & Iacono, 1991). Although defense
attorneys often attempt to have the results of friendly CQTs admitted as
evidence in court, there is no evidence supporting their validity and ample
reason to doubt it. Members of scientific organizations who have the
requisite background to evaluate the CQT are overwhelmingly skeptical of
the claims made by polygraph proponents. [27]
Summarizing the consensus in psychological research, professor David W.
Martin, PhD, from North Carolina State University, states that people have
tried to use the polygraph for measuring human emotions, but there is
simply no royal road to (measuring) human emotions.[28] Therefore, since
one cannot reliably measure human emotions (especially when one has an
interest in hiding his/her emotions), the idea of valid detection of truth or
falsehood through measuring respiratory rate, blood volume, pulse rate and
galvanic skin response is a mere pretense. Since psychologists cannot
ascertain what emotions one has,[29] polygraph professionals are not able
to do that either.
Polygraphy has also been faulted for failing to trap known spies such as
double-agent Aldrich Ames, who passed two polygraph tests while spying for
the Soviet Union.[26][30] Other spies who passed the polygraph include Karl
Koecher,[31] Ana Belen Montes,[32] and Leandro Aragoncillo.[33] However,
CIA spy Harold James Nicholson failed his polygraph examinations, which
aroused suspicions that led to his eventual arrest.[34] Polygraph
examination and background checks failed to detect Nada Nadim Prouty,
who was not a spy but was convicted for improperly obtaining US citizenship
and using it to obtain a restricted position at the FBI.[35]
The polygraph also failed to catch Gary Ridgway, the "Green River Killer".
Ridgway passed a polygraph in 1984 and confessed almost 20 years later
when confronted with DNA evidence.[36]
Conversely, innocent people have been known to fail polygraph tests. In
Wichita, Kansas in 1986, after failing two polygraph tests (one police
administered, the other given by an expert that he had hired), Bill Wegerle
had to live under a cloud of suspicion of murdering his wife Vicki Wegerle,
even though he was neither arrested nor convicted of her death. In March
2004, a letter was sent to The Wichita Eagle reporter Hurst Laviana that
contained Vicki's drivers license and what first appeared to be crime scene
photographs of her body. The photos had actually been taken by her true
murderer, BTK,[37] the serial killer that had plagued the people of Wichita
since 1974 and had recently resurfaced in February 2004 after an apparent
25 year period of dormancy (he had actually killed three women between
1985 and 1991, including Wegerle). That effectively cleared Bill Wegerle of
the murder of his wife. In 2005 conclusive DNA evidence, including DNA
retrieved from under the fingernails of Vicki Wegerle, demonstrated that the
BTK Killer was Dennis Rader.[38]
Prolonged polygraph examinations are sometimes used as a tool by which
confessions are extracted from a defendant, as in the case of Richard Miller,
who was persuaded to confess largely by polygraph results combined with
appeals from a religious leader.[39]
Law enforcement agencies and intelligence agencies in the United States
are by far the biggest users of polygraph technology. In the United States
alone all federal law enforcement agencies either employ their own
polygraph examiners or use the services of examiners employed in other
agencies.[40] This is despite persistent claims of unreliability. For example in
1978 Richard Helms, the 8th Director of Central Intelligence, stated that:
"We discovered there were some Eastern Europeans who could defeat the
polygraph at any time. Americans are not very good at it, because we are
raised to tell the truth and when we lie it is easy to tell [we] are lying. But we
find a lot of Europeans and Asiatics [who] can handle that polygraph without
a blip, and you know they are lying and you have evidence that they are
lying."[41]
[edit] Countermeasures
Several countermeasures designed to pass polygraph tests have been
described. Asked how he passed the polygraph test, Ames explained that he
sought advice from his Soviet handler and received the simple instruction to:
"Get a good night's sleep, and rest, and go into the test rested and relaxed.
Be nice to the polygraph examiner, develop a rapport, and be cooperative
and try to maintain your calm."[42]
Other suggestions for countermeasures include for the subject to mentally
record the control and relevant questions as the examiner reviews them
prior to commencing the interrogation. Once the interrogation begins, the
subject is then supposed to carefully control their breathing during the
relevant questions, and to try to artificially increase their heart rate during
the control questions, such as by thinking of something scary or exciting or
by pricking themselves with a pointed object concealed somewhere on their
body. In this way the results will not show a significant reaction to any of the
relevant questions.[43][44]
[edit] 2003 National Academy of Sciences report
The accuracy of the polygraph has been contested almost since the
introduction of the device. In 2003, the National Academy of Sciences (NAS)
issued a report entitled "The Polygraph and Lie Detection". The NAS found
that the majority of polygraph research was "Unreliable, Unscientific and
Biased", concluding that 57 of the approximately 80 research studies that
the APA relies on to come to their conclusions were significantly flawed.
These studies did show that specific-incident polygraph testing, in a person
untrained in counter-measures, could discern the truth at "a level greater
than chance, yet short of perfection". However, due to several flaws, the
levels of accuracy shown in these studies "are almost certainly higher than
actual polygraph accuracy of specific-incident testing in the field".[45]
When polygraphs are used as a screening tool (in national security matters
and for law enforcement agencies for example) the level of accuracy drops
to such a level that "Its accuracy in distinguishing actual or potential security
violators from innocent test takers is insufficient to justify reliance on its use
in employee security screening in federal agencies." In fact, the NAS
extrapolated that if the test were sensitive enough to detect 80% of spies (a
level of accuracy which it did not assume), this would hardly be sufficient
anyway. Let us take for example a hypothetical polygraph screening of a
body of 10,000 employees among which are 10 spies. With an 80% success
rate, the polygraph test would show that 8 spies and 1,992 non-spies fail the
test. Thus, roughly 99.6 percent of positives (those failing the test) would be
false positives. The NAS concluded that the polygraph "...may have some
utility"[45] but that there is "little basis for the expectation that a polygraph
test could have extremely high accuracy."[45]:212
The NAS conclusions paralleled those of the earlier United States Congress
Office of Technology Assessment report "Scientific Validity of Polygraph
Testing: A Research Review and Evaluation”.[46]
From Wikipedia, the free encyclopedia
A polygraph (popularly referred to as a lie detector) is an instrument that
measures and records several physiological indices such as blood pressure,
pulse, respiration, and skin conductivity while the subject is asked and
answers a series of questions, in the belief that deceptive answers will
produce physiological responses that can be differentiated from those
associated with non-deceptive answers.
Polygraphy is widely rejected as being pseudoscience by the scientific
community.[1] Nonetheless, polygraphs are in some countries used as an
interrogation tool with criminal suspects or candidates for sensitive public or
private sector employment. US federal government agencies such as the
FBI and the CIA and many police departments such as the LAPD use
polygraph examinations to interrogate suspects and screen new employees.
Within the US federal government, a polygraph examination is also referred
to as a psychophysiological detection of deception (PDD) examination.
History
The idea that lying produces physical side-effects has long been claimed. In
West Africa persons suspected of a crime were made to pass a ostrich's egg
to one another.[citation needed] If a person broke the egg, then he or she
was considered guilty, based on the idea that their nervousness was to
blame. In ancient China the suspect held a handful of rice in his or her
mouth during a prosecutor's speech.[citation needed] Because salivation
was believed to cease at times of emotional anxiety, the person was
considered guilty if by the end of that speech the rice was dry.
Early devices for lie detection include an 1885 invention of Cesare
Lombroso used to measure changes in blood pressure for police cases, a
1904 device by Vittorio Benussi used to measure breathing, and an
abandoned project by American William Marston which used blood pressure
and galvanic skin response to examine German prisoners of war (POWs).[2]
Marston wrote a second paper on the concept in 1915, when finishing his
undergraduate studies. He entered Harvard Law School and graduated in
1918, re-publishing his earlier work in 1917.[3] According to their son,
Marston's wife, Elizabeth Holloway Marston, was also involved in the
development of the systolic blood pressure test: "According to Marston’s
son, it was his mother Elizabeth, Marston’s wife, who suggested to him that
'When she got mad or excited, her blood pressure seemed to climb' (Lamb,
2001). Although Elizabeth is not listed as Marston’s collaborator in his early
work, Lamb, Matte (1996), and others refer directly and indirectly to
Elizabeth’s work on her husband’s deception research. She also appears in
a picture taken in his polygraph laboratory in the 1920s (reproduced in
Marston, 1938)."[4][5] The comic book character, Wonder Woman, by
William Marston (and influenced by Elizabeth Marston[6][7]) carries a magic
lasso which was modelled upon the pneumograph (breathing monitor) test.[6]
[8]
Marston was the self-proclaimed “father of the polygraph” despite his
predecessor's contributions. Marston remained the device's primary
advocate, lobbying for its use in the courts. In 1938 he published a book,
The Lie Detector Test, wherein he documented the theory and use of the
device.[9] In 1938 he appeared in advertising by the Gillette company
claiming that the polygraph showed Gillette razors were better than the
competition.[10][11][12]
A device recording both blood pressure and galvanic skin response was
invented in 1921 by Dr. John A. Larson of the University of California and
first applied in law enforcement work by the Berkeley Police Department
under its nationally renowned police chief August Vollmer. Further work on
this device was done by Leonarde Keeler.[13]
Several devices similar to Keeler's polygraph version included the Berkeley
Psychograph, a blood pressure-pulse-respiration recorder developed by C.
D. Lee in 1936[14] and the Darrow Behavior Research Photopolygraph,
which was developed and intended solely for behavior research experiments.
[14][15]
A device which recorded muscular activity accompanying changes in blood
pressure was developed in 1945 by John E. Reid, who claimed that greater
accuracy could be obtained by making these recordings simultaneously with
standard blood pressure-pulse-respiration recordings.[14][16]
[edit] Testing procedure
Globe icon.
The examples and perspective in this section may not represent a
worldwide view of the subject. Please improve this article and discuss the
issue on the talk page. (April 2010)
Today, polygraph examiners use two types of instrumentation: analog and
computerized. In the United States, most examiners now use computerized
instrumentation.[citation needed]
A typical polygraph test starts with a pre-test interview to gain some
preliminary information which will later be used for "control questions", or
CQ. Then the tester will explain how the polygraph is supposed to work,
emphasizing that it can detect lies and that it is important to answer
truthfully. Then a "stim test" is often conducted: the subject is asked to
deliberately lie and then the tester reports that he was able to detect this lie.
Then the actual test starts. Some of the questions asked are "irrelevant" or
IR ("Is your name Chris?"), others are "probable-lie" control questions that
most people will lie about ("Have you ever stolen money?") and the
remainder are the "relevant questions", or RQ, that the tester is really
interested in. The different types of questions alternate. The test is passed if
the physiological responses during the probable-lie control questions (CQ)
are larger than those during the relevant questions (RQ). If this is not the
case, the tester attempts to elicit admissions during a post-test interview, for
example, "Your situation will only get worse if we don't clear this up".[17][18]
Criticisms have been given regarding the validity of the administration of the
Comparative Questions test (CQT). The CQT may be vulnerable to being
conducted in an interrogation-like fashion. This kind of interrogation style
would elicit a nervous response from innocent and guilty suspects alike.
There are several other ways of administrating the questions.
An alternative is the Guilty Knowledge Test (GKT), or the Concealed
Information Test (CIT). The administration of this test is given to prevent
potential errors that may arise from the questioning style. The test is usually
conducted by a tester with no knowledge of the crime or circumstances in
question. The administrator tests the participant on their knowledge of the
crime that would not be known to an innocent person. For example: "Was
the crime committed with a .45 or a 9 mm?" The questions are in multiple
choice and the participant is rated on how they react to the correct answer.
If they react strongly to the guilty information, then proponents of the test
believe that it is likely that they know facts relevant to the case. This
administration is considered more valid by supporters of the test because it
contains many safeguards to avoid the risk of the administrator influencing
the results.[19]
[edit] Validity
Polygraphy has little credibility among scientists.[20][21] Despite claims of
90-95% validity by polygraph advocates, and 95-100% by businesses
providing polygraph services,[22] critics maintain that rather than a "test",
the method amounts to an inherently unstandardizable interrogation
technique whose accuracy cannot be established. A 1997 survey of 421
psychologists estimated the test's average accuracy at about 61%, a little
better than chance.[23] Critics also argue that even given high estimates of
the polygraph's accuracy a significant number of subjects (e.g. 10% given a
90% accuracy) will appear to be lying, and would unfairly suffer the
consequences of "failing" the polygraph. In the 1998 Supreme Court case,
United States v. Scheffer, the majority stated that "There is simply no
consensus that polygraph evidence is reliable" and "Unlike other expert
witnesses who testify about factual matters outside the jurors' knowledge,
such as the analysis of fingerprints, ballistics, or DNA found at a crime
scene, a polygraph expert can supply the jury only with another opinion..."
[24] Also, in 2005 the 11th Circuit Court of Appeals stated that “polygraphy
did not enjoy general acceptance from the scientific community”.[25] Charles
Honts, a psychology professor at Boise State University, states that
polygraph interrogations give a high rate of false positives on innocent
people.[26] In 2001 William G. Iacono, Distinguished McKnight University
Professor of Psychology and Neuroscience and Director, Clinical Science
and Psychopathology Research Training Program at the University of
Minnesota, published a paper titled “Forensic “Lie Detection": Procedures
Without Scientific Basis” in the peer reviewed Journal of Forensic
Psychology Practice. He concluded that
Although the CQT [Control Question Test] may be useful as an investigative
aid and tool to induce confessions, it does not pass muster as a scientifically
credible test. CQT theory is based on naive, implausible assumptions
indicating (a) that it is biased against innocent individuals and (b) that it can
be beaten simply by artificially augmenting responses to control questions.
Although it is not possible to adequately assess the error rate of the CQT,
both of these conclusions are supported by published research findings in
the best social science journals (Honts et al., 1994; Horvath, 1977;
Kleinmuntz & Szucko, 1984; Patrick & Iacono, 1991). Although defense
attorneys often attempt to have the results of friendly CQTs admitted as
evidence in court, there is no evidence supporting their validity and ample
reason to doubt it. Members of scientific organizations who have the
requisite background to evaluate the CQT are overwhelmingly skeptical of
the claims made by polygraph proponents. [27]
Summarizing the consensus in psychological research, professor David W.
Martin, PhD, from North Carolina State University, states that people have
tried to use the polygraph for measuring human emotions, but there is
simply no royal road to (measuring) human emotions.[28] Therefore, since
one cannot reliably measure human emotions (especially when one has an
interest in hiding his/her emotions), the idea of valid detection of truth or
falsehood through measuring respiratory rate, blood volume, pulse rate and
galvanic skin response is a mere pretense. Since psychologists cannot
ascertain what emotions one has,[29] polygraph professionals are not able
to do that either.
Polygraphy has also been faulted for failing to trap known spies such as
double-agent Aldrich Ames, who passed two polygraph tests while spying for
the Soviet Union.[26][30] Other spies who passed the polygraph include Karl
Koecher,[31] Ana Belen Montes,[32] and Leandro Aragoncillo.[33] However,
CIA spy Harold James Nicholson failed his polygraph examinations, which
aroused suspicions that led to his eventual arrest.[34] Polygraph
examination and background checks failed to detect Nada Nadim Prouty,
who was not a spy but was convicted for improperly obtaining US citizenship
and using it to obtain a restricted position at the FBI.[35]
The polygraph also failed to catch Gary Ridgway, the "Green River Killer".
Ridgway passed a polygraph in 1984 and confessed almost 20 years later
when confronted with DNA evidence.[36]
Conversely, innocent people have been known to fail polygraph tests. In
Wichita, Kansas in 1986, after failing two polygraph tests (one police
administered, the other given by an expert that he had hired), Bill Wegerle
had to live under a cloud of suspicion of murdering his wife Vicki Wegerle,
even though he was neither arrested nor convicted of her death. In March
2004, a letter was sent to The Wichita Eagle reporter Hurst Laviana that
contained Vicki's drivers license and what first appeared to be crime scene
photographs of her body. The photos had actually been taken by her true
murderer, BTK,[37] the serial killer that had plagued the people of Wichita
since 1974 and had recently resurfaced in February 2004 after an apparent
25 year period of dormancy (he had actually killed three women between
1985 and 1991, including Wegerle). That effectively cleared Bill Wegerle of
the murder of his wife. In 2005 conclusive DNA evidence, including DNA
retrieved from under the fingernails of Vicki Wegerle, demonstrated that the
BTK Killer was Dennis Rader.[38]
Prolonged polygraph examinations are sometimes used as a tool by which
confessions are extracted from a defendant, as in the case of Richard Miller,
who was persuaded to confess largely by polygraph results combined with
appeals from a religious leader.[39]
Law enforcement agencies and intelligence agencies in the United States
are by far the biggest users of polygraph technology. In the United States
alone all federal law enforcement agencies either employ their own
polygraph examiners or use the services of examiners employed in other
agencies.[40] This is despite persistent claims of unreliability. For example in
1978 Richard Helms, the 8th Director of Central Intelligence, stated that:
"We discovered there were some Eastern Europeans who could defeat the
polygraph at any time. Americans are not very good at it, because we are
raised to tell the truth and when we lie it is easy to tell [we] are lying. But we
find a lot of Europeans and Asiatics [who] can handle that polygraph without
a blip, and you know they are lying and you have evidence that they are
lying."[41]
[edit] Countermeasures
Several countermeasures designed to pass polygraph tests have been
described. Asked how he passed the polygraph test, Ames explained that he
sought advice from his Soviet handler and received the simple instruction to:
"Get a good night's sleep, and rest, and go into the test rested and relaxed.
Be nice to the polygraph examiner, develop a rapport, and be cooperative
and try to maintain your calm."[42]
Other suggestions for countermeasures include for the subject to mentally
record the control and relevant questions as the examiner reviews them
prior to commencing the interrogation. Once the interrogation begins, the
subject is then supposed to carefully control their breathing during the
relevant questions, and to try to artificially increase their heart rate during
the control questions, such as by thinking of something scary or exciting or
by pricking themselves with a pointed object concealed somewhere on their
body. In this way the results will not show a significant reaction to any of the
relevant questions.[43][44]
[edit] 2003 National Academy of Sciences report
The accuracy of the polygraph has been contested almost since the
introduction of the device. In 2003, the National Academy of Sciences (NAS)
issued a report entitled "The Polygraph and Lie Detection". The NAS found
that the majority of polygraph research was "Unreliable, Unscientific and
Biased", concluding that 57 of the approximately 80 research studies that
the APA relies on to come to their conclusions were significantly flawed.
These studies did show that specific-incident polygraph testing, in a person
untrained in counter-measures, could discern the truth at "a level greater
than chance, yet short of perfection". However, due to several flaws, the
levels of accuracy shown in these studies "are almost certainly higher than
actual polygraph accuracy of specific-incident testing in the field".[45]
When polygraphs are used as a screening tool (in national security matters
and for law enforcement agencies for example) the level of accuracy drops
to such a level that "Its accuracy in distinguishing actual or potential security
violators from innocent test takers is insufficient to justify reliance on its use
in employee security screening in federal agencies." In fact, the NAS
extrapolated that if the test were sensitive enough to detect 80% of spies (a
level of accuracy which it did not assume), this would hardly be sufficient
anyway. Let us take for example a hypothetical polygraph screening of a
body of 10,000 employees among which are 10 spies. With an 80% success
rate, the polygraph test would show that 8 spies and 1,992 non-spies fail the
test. Thus, roughly 99.6 percent of positives (those failing the test) would be
false positives. The NAS concluded that the polygraph "...may have some
utility"[45] but that there is "little basis for the expectation that a polygraph
test could have extremely high accuracy."[45]:212
The NAS conclusions paralleled those of the earlier United States Congress
Office of Technology Assessment report "Scientific Validity of Polygraph
Testing: A Research Review and Evaluation”.[46]
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