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The Polygraph as a Truth Detector
by William Trevino
1984
Summary
The B.C. Civil Liberties Association believes that there is convincing evidence
to suggest that the use of the polygraph is arbitrary, subjective, biased toward
accusations of guilt and claims of very high validity are scientifically
indefensible. However, even if one is not willing to be persuaded by evidence on
these matters, one must admit, at the very least, that there is no scientific
opinion whatsoever concerning the validity of polygraph testing. In fact, there
is extremely wide divergence over the validity of the test.
In these circumstances, the onus is clearly on the proponents of the polygraph
test to establish a convincing scientific case for the claims of high validity
that are made by polygraph operators. In other words, the burden of proof rests
with the lie detector industry to satisfy the scientific community and
legislators that there is convincing evidence to support claims of ninety
percent or greater accuracy that are commonly made by polygraph operators.
Without such agreement, it seems utterly irresponsible to allow the use of such
a device in situations where it may ultimately interfere with the liberty of
innocent citizens.
The B.C. Civil Liberties Association urges the Government of British Columbia to
follow the example of Ontario in banning the mandatory use of polygraphs by
employers in the province. We would go further: since the evidence we have
presented throws considerable shadows of doubt on the usefulness of the
polygraph test per se, we see no useful purpose for the procedure as either
screening procedure for police candidates, or in the court system generally,
both of which are uses allowed by Ontario, though there is no convincing
evidence in support of the test in any situation. Ontario's compendium of
information, including the Morand Report, in their 1983 amendment to their
Employment Standards Act leads one to conclusions very similar to the B.C. Civil
Liberties Association's: the polygraph test is a humbug of subjective, arbitrary
and contradictory procedures that does not detect lies or guilt any more
effectively, and in many cases not as well (because of procedural and machine
bias), as interviews and cross examination that are already common tools of
psychology, police work and the courts. The compounded danger in the instances
of polygraphs lies in the sanctioned role that untrained persons with crude
devices play in harrying innocent persons in commercial and legal settings. To
paraphrase an expert, it is the idiocy of idiocies. We urge its removal as an
avenue of arbitrary persecution.
The background
The polygraph procedure and machine is an accretion of 1930s technology and
popularized psychology rooted not in practices of modern science, but rather
based on the traditions of polygraph testing itself. In that sense, a polygraph
examination is a self-fulfilling process, "measuring" a series of physical signs
without the machine and drawing subjective, psychological sounding conclusions
in varying ways depending upon the mental state and set and training of each,
and the rapport between both, the examination subject and the examiner. The
result of this exercise, associative of the monitoring machines of Scientology,
is a series of conclusions about the veracity of specific statements or guilt
generally, conclusions unsupportable by consistent scientific logic or by
confirmation by other means. In fact, there is convincing evidence to suggest
that the procedure is much more likely to create victims of false allegation
than it is likely to detect purveyors of falsehood or paragons of guilt-however
falsehood or guilt may be defined. The statistical illustration at the end of
the paper provides an illustration of this phenomenon.
To read the rest of this article go to http://www.police-test.net/polygrapha1.htm
William Trevino
Retired air force master sergeant who now offers advice to discredit the
polygraph machine as a truth detector.
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