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Trial By Ordeal? Polygraph Testing In Australia

Author: Ben Clarke LLB (Tasmania) LLM (Bristol)
Lecturer, Notre Dame University of Australia School of Law
Issue: Volume 7, Number 1 (March 2000)



Trial By Ordeal? Polygraph Testing In Australia

    What are Polygraphs?

  1. A Polygraph or "lie detector" is "an instrument used to measure the autonomic nervous system responses in terms of blood pressure, pulse rate, respiration rate and galvanic skin response. In theory when a person tells a lie, fear of detection causes uncontrollable reactions in these physiological areas which the polygraph indicates with inked lines on a moving paper scroll". [1]

  2. The use of polygraphs in sensitive areas such as the questioning of suspects in criminal cases, recruitment processes (eg by the FBI), investigation of insurance fraud and interrogation of current or potential employees raises certain ethical issues. In particular, the appropriateness of compelling, or coercing people to undertake such testing needs to be examined. The use of polygraphs also raises the broader question of whether we want to live in a society that is dominated by this type of testing.

    Validity and Accuracy

  3. There is considerable debate about the validity and accuracy of lie detector tests in the questioning of crime suspects and others[2] and indeed about the validity of the technique as a whole.[3]

  4. The most obvious concern is that lie detectors do not actually tell you whether the subject has lied but rather feed on physiological responses recorded during the questioning of a person.

  5. An example of where polygraphs can give erroneous "results" is when nervous persons are tested. Persons of a nervous disposition may display galvanic responses, which may be interpreted as indicating that the person is lying when they are answering questions truthfully but are feeling stressed.

  6. Others are able to 'beat the lie detector'. One method may be for a person to state a proposition numerous times until the person accepts its validity and consequently passes a lie detector test. Eg "the earth is square, the earth is square....".

  7. Even proponents of polygraphs recognize a large number of categories of people have been deemed unsuitable for polygraph testing.[4]

  8. Concerns about the validity and use of polygraph testing have been voiced by the American Medical Association, the American Civil Liberties Union, psychologists, and congressional representatives.[5]

  9. In 1988 the United States Congress passed the Employment Polygraph Protection Act which protects most private sector employees from polygraph testing, except in a few sensitive fields of employment (eg where national security is at stake).

    Admissibility of Polygraph Results

    The American Approach

  10. In the United States of America, (where polygraph testing is a growth industry) the admissibility of lie detector test results is determined by courts and legislators on a State by State basis.

  11. In the Federal legal system, test results are inadmissible as substantive evidence.[6] Whilst some States have allowed test results in criminal trials, States such as such as California have prohibited the admission of such evidence unless all parties consent to its admission.[7] Other States such as Illinios completely bar the use of such testing in criminal trials. This prohibition extends to requesting, requiring or suggesting that a defendant submit to such a test.[8]

  12. The preponderance of authority in the United States is against the admission of polygraph evidence with a variety of grounds having been asserted for refusing its admissibility including: -

    1. It intrudes on the ultimate issue which the Court must determine.
    2. It does not fulfil the criteria of the Supreme Court of the United States test in Frye Case[9] with regard to admitting scientific evidence.
    3. It is hearsay evidence.
    4. It relates to the credit of witnesses not suffering psychiatric illnesses and is therefore not a proper matter for expert evidence.
    5. The elicitation of the responses is unfair because of the trickery and deceit necessary to obtain responses.
    6. The testimony is self-serving for the Defendant.[10]

    In Fryes Case[11] the court held that evidence obtainable from the use of scientific instruments or techniques is admissible if the instrument or technique has a reasonable measure of precision and is accepted in its scientific field or profession.

  13. More recently, the approach of US courts has been to admit evidence where there is recognition by specialists within a profession or field of science, even though the wider professional or scientific group may be unfamiliar with the technique.[12]

    The Common Law Approach

  14. The Supreme Court of Canada in Phillion's case rendered evidence of the results of a lie detector test inadmissible. [13]

  15. A Scottish Court has followed this approach noting that the use of such techniques distorts the adversarial trial process.[14]

  16. Neither the Privy Council nor the House of Lords have had the opportunity to consider this question.

    The Australian Approach

  17. The admissibility of polygraph tests has not yet been considered by the High Court of Australia. It has however been raised in inferior courts.

  18. In Raymond George Murray[15] His Honour Judge Sinclair DCJ of the New South Wales District Court applied Phillion and held that results from polygraph examinations undertaken by an accused (with a view to substantiating his denial of the substance of the charge against him) were inadmissible evidence in the course of a criminal trial.[16]

  19. In that case His Honour Mr Sinclair DCJ heard evidence on a voir dire from an expert witness who described himself as a Polygraph Examiner.

  20. A Mr. Glare gave evidence of having tested the accused by asking a series of questions and monitoring the accused's respiration, blood pressure, pulse rate and galvanic skin reaction of the accused. The questions went to the heart of the charges for which the accused stood trial and were as follows:-

    1. At 6.30pm on 7 July 1980 at Cremorne did you fire any shots from a firearm? Answer - No.
    2. At about 6.30pm on 7 July 1980 at Cremorne did you point a firearm at these Police? Answer - No.
    3. At about 6.30pm on 7 July 1980 at Cremorne did you say to those Police "You are not going to arrest me. I'm not going to jail". Answer - No.
    4. Did you say to these Police "I mean I tried to shoot him"? Answer - No.

    The responses were recorded on a polygraph chart, which Mr Glare interpreted as disclosing that "In his opinion the accused was speaking the truth in regard to the relevant questions".[17]

  21. His Honour held that as a question of law this evidence was inadmissible for the following reasons: -

    1. The sole purpose of the evidence is to bolster the credit the accused as a witness. However, the veracity of the accused and the weight to be given to his evidence, and other witnesses called in the trial, is a matter for the jury to assess and on general principals such evidence as adduced by Counsel is excluded.
    2. The witness seeks to express an opinion as to ultimate facts in issue, which is peculiarly the providence of the jury to determine on facts presented by them by witnesses who perceive them by the exercise of their physical senses.
    3. It purports to be expert evidence by the witness is not qualified as an expert, he is merely an operator and assessor of a polygraph. Furthermore the scientific premise upon which his assessment is based has not been proved in this Court or in any Court in Australia. (italics added)
    4. Devoid of any proved or accepted scientific basis, the evidence of Mr Glare is simply hearsay which is inadmissible and of no probative value.[18]

    In referring to the Canadian authority of Phillian His Honour noted that in the Canadian case the polygraph operator "like Mr Glare was neither a psychologist nor a psychiatrist though he had considerably more experience in the operation of an interpretation of the readings of the polygraph than Mr Glare".[19]

  22. His Honour went on to note that "Whatever may be the situation in some States of the United States of America, this "evangelical sideline", as it was described, in passing, by Mr Glare, which no doubt holds a genuine fascination for some people, has no place in a criminal trial in New South Wales.".[20]

    Statutory Restrictions on Polygraphs

  23. With the exception of the New South Wales Lie Detectors Act (1983), there is no legislation in Australia specifically prohibiting the admission of lie detector evidence in criminal trials. It would be interesting to see how a Court outside of New South Wales would respond to a case where all parties consented to the admission of lie detector evidence interpreted by an experienced well qualified and recognised Psychiatrist or Psychologist.

  24. It may be the case that a Prosecutor who doubts the veracity of a complainant's account may wish to invite a complainant to undertake a lie detector test. The defence may well support such an approach, as a finding that the complainant "had lied" on the lie detector test may well persuade the prosecution to proceed no further with the case.

  25. Such examination of the complainant would be a double-edged sword. If the complainant "passed" the lie detector test, then if this evidence was deemed admissible in the criminal trial, the defendant's position could be severely prejudiced. It would therefore seem unlikely that defence lawyers would support the admissions polygraph evidence, unless the accused or other defence witnesses had "passed" the test, or prosecution witnesses had "failed it".

    The Lie Detectors Act 1983

  26. Concern in New South Wales about the use or misuse of lie detectors by employers, insurance investigators and others has led to the enactment of the Lie Detectors Act 1983 (NSW). ("the Act")

  27. The Act prohibits requesting or requiring another person to undergo an examination based on the use of instruments or apparatus which monitor the physical reactions of the body or elements of stress, tone or variation or vibration in the voice for any prohibited purpose. [21]

  28. Prohibited purpose is defined in the Act to mean any purpose connected with:-

    1. Matters relating to employment including application for or offer of employment, honesty and other means related to character terms of employment, promotion and other employment related benefits, transfer of employment, training in or continuation of employment.
    2. Consideration of the acceptance of risk under a proposal for a contract or policy of insurance.
    3. Consideration of a claim under an insurance policy or payment of compensation for loss or damage under an insurance policy or an application for any form of financial accommodation.
    4. Establishing whether or not a person is guilty of an act or admission that is punishable by a fine or imprisonment.[22]

  29. Given the difficulties associated with lie detector tests, it would be appropriate for similar legislation to be enacted throughout Australia. Further, such legislation should include an additional category extending the prohibition on the use of lie detectors to the questioning suspects in criminal matters.

    Polygraphs in Civil Litigation

  30. Putting aside the difficulties of the rule against hearsay and expert evidence, polygraph test results could prove extremely useful in civil trials, particularly small debt claims and other relatively minor civil matters. Where parties to a dispute consented to testing by an independent suitably qualified psychiatrist or psychologist, should a Tribunal have regard to the results of these tests in weighing all of the evidence? It may be that such an approach would save court time and be of great assistance in minor matters such as small claim disputes. It would appear from the following case, that such innovation has already attracted the interest of at least one American court.

  31. In a New York civil suit, it was ordered that both parties were to submit to polygraph examinations. The case concerned an alleged oral loan of $1,010.00. The Judge explained his ruling by stating:

    "Even the wisdom of a King Solomon would be tried in a case such as this and that the particular situation presented an ideal situation for the use of such tests".[23]


  32. It is doubtful that results from lie detector tests will ever be held admissible in Australian criminal courts. While proponents of polygraph evidence claim that test results are a definitive indication of the veracity of an accused's denial of guilt, such the results are hearsay and amount to a self-serving statement which is inadmissible at both common law, and pursuant to statutory rules of evidence. Further, there does not appear to be any general acceptance of the validity and reliability of polygraphs within the Australian scientific community.

  33. It is extremely doubtful that polygraphs will ever gain general acceptance within the scientific community. There are simply too many reasons why polygraphs results or interpretations of test results may be flawed. Indeed reliance on these instruments as an indicator of the veracity of a subject's testimony is reminiscent of archaic judicial methods of determining guilt or innocence.

  34. Does the coercion of people to undertake lie detector tests vary significantly from subjecting hapless women in the dark ages to trial by ordeal? Do these devices any more accurately determined truth? Or have we simply invented a modern form of witch dunking?

  35. While the scientific merit of witch dunking would be hard to fathom in any era, the reliability and accuracy of polygraph machines has been extensively tested.[24] The results of these tests have produced little scientific support for polygraphs as a method of detecting the truth. Stories about the inaccuracy of these devices are legion.

    In a deserving study, Patrick and Iacono (1989) offered prison inmates, half of the psychopaths, $20.00 to beat the polygraph. The psychopath did a little better than the non -psychopath but the significant finding was that, using the control question technique, the polygraph examiners wrongly classified 45% of innocent subjects as guilty of crimes. In a later experiment conducted with the polygraph division of the Royal Canadian Mountain Police [Patrick and Iacono (1991)] the experimenters found further evidence to support the contention that the control question technique misidentified nearly half of innocent suspects as liars.[25]

  36. The problematic nature of polygraphs goes beyond the ability of participants to trick lie detector machines. Different conclusions may be drawn from the same polygraph data - leading to interpretations being challenged on the grounds of their subjectivity.[26] The lack of validation of industry standards for polygraphs further undermines attempts to admit polygraph results as evidence in courts of law.

  37. There is a need for uniform national legislation to prevent invasive polygraph testing from impinging upon the privacy rights of employees, accused persons and the public in general in their dealings with various public and private sector agencies.

  38. Polygraphs could only be admitted into evidence in Australian courts if there is: 1. significant re-writing of the common law rules of evidence, and 2. general recognition of the validity, reliability and accuracy of polygraph testing within the Australian scientific community.

  39. Until that time, Australian courts will continue to rely on that tried, trusted and time-honoured common law lie detector, the 12 men and women of the jury.

Acknowledgment: Many thanks to Ian Deardon, and also my sister Kirsty Clarke, for her useful comments on an earlier draft of this paper. Thanks also to Professor Neil McLeod for his helpful comments on a previous version of the paper.


[1] Brian Lane, Encyclopedia of Forensic Science (Headline Book Publishing PLC,1992), p 321.

[2] American Civil Liberties Union (ACLU)Briefing Paper No 4 : Lie Detector Testing (Internet) URL:

[3] Susan McCarthy "The Truth about the Polygraph", Health & Body March 2 2000 (Internet) URL:

[4] Psychopathic liars, demented or abnormal persons, persons who are emotionally unfit, a heart condition, who have been in prison for a long time, who are hungry or thirsty, alcoholics, children under the age of reason, persons under medication or narcotics, over tired persons or people with colds, sneezing or coughing or suffering from emphysema are all unsuitable to be tested by polygraph. supra Lane page 322

[5] Supra ACLU p 1

[6] United States v Hunter 672F.2d815 [TENTH CIR.1982]

[7] Wests Ann.Evidence Code 351.1

[8] Illinios Rev.Stats., ch.38,155-11

[9] Frye v United States, 54 App.D.C. 46, 293 F. 1013 (1923)

[10] Page LBC Update Freckelton and Selby 1-1890

[11] Supra n9

[12] People v Williams 164 Cal. App. 2nd Supp. 858, 331 P.2nd 251 (1958)

[13] Phillion v R 1978 1SCR 18

[14] Meehan (Petitioner) 1970 JC11

[15] Raymond George Murray 1982 7A Crim R48

[16] ibid. p48

[17] ibid. p49

[18] ibid.

[19] Ibid. p50

[20] ibid

[21] Section 5(2) of the Lie Detectors Act 1983

[22] Section 6 of the Lie Detectors Act 1983

[23] Walther v O'Connell, 72MISC.2D316, 339 NYS2d 386 [Queens County Civil CT., NY City 1972]

[24] supra ACLU p1

[25] OPSIT Page 1/189 [LBC]

[26] cf: Lykken, D.T., A Tremor in the Blood, Uses and Abuses of the Lie Detector (1980)

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