Where do we stand with polygraphs?

November 2005

Where do we stand with polygraphs?

bouton-vers-francaisA polygraph is a machine also commonly referred to as a “lie detector” which, some say, allows one to determine whether or not a person is telling the truth. It is used occasionally at the request of claims adjusters and, less often, by individuals wishing to add weight to their insurance claims. However, the courts have been reluctant to admit into evidence polygraph tests—whose results are interpreted by an expert polygraphist who determines whether or not a person is telling the truth—because the majority of courts do not want to relinquish their power to determine the quality and credibility of testimony.
A polygraph is a machine and was described as follows by Mr. Justice Chevalier in Blanchette v. La Garantie, Compagnie d’assurance de l’Amérique du Nord1

“The person being questioned is hooked up to the machine:

  • First by two rubber tubes that are placed on the thorax and record changes in the person’s breathing
  • Second by electrodes that are attached to two fingers of the left hand and react to the sweat released through the pores
  • Thirdly by an armband filled with air that is placed around the person’s arm and measures the blood flow and reverse blood flow and that is of the same nature as the cuffs used by doctors to check a patient’s blood pressure
  • The reactions are recorded on four separate lines. Starting from the top, the first two lines record upper and lower thoracic breathing. The third records sweating. The fourth records blood pressure.”

Although this description of the “mechanics” dates back to 1984, for 2005 purposes it is sufficient to note that all the information collected during a test is now recorded on computer and displayed by way of computer graphics.
Finally, it should be noted that polygraph tests are generally recorded with a video camera equipped with sound.

Scientific proof

A recent judgment confirms the reluctance of the courts to admit evidence of a polygraph test to prove the credibility of a witness.
In Hydro-Québec v. Michel Désaulniers, (judgment dated July 8, 2005, The Honourable Raynald Fréchette, Superior Court, 455-05-000053-962), the court rejected the results of a polygraph test and the testimony of the polygraphist.
Mr. Désaulniers had been sued by Hydro-Québec for stealing electricity. He contested Hydro-Québec’s claim and filed a counterclaim. Hydro-Québec alleged he had tampered with the meter.
To prove his honesty and the fact that he had not had anything to do with the modifications made to the meter, Mr. Désaulniers submitted to a polygraph test.
The majority of caselaw has set aside such evidence (Hôtel Central (Victoriaville) inc. v. Compagnie d’assurance Reliance).2 The reasons were repeated and further clarified in Vêtements Paul Allaire inc. v. Citadelle, compagnie d’assurances générales inc.3 and in Dunn v. Compagnie d’assurance Missisquoi,4 where the lack of scientific evidence capable of supporting polygraphs was raised:


“No evidence was provided regarding the reliability of the machine used which, unlike a breathalyser, has not received government certification. Furthermore, no scientific or medical evidence was presented to support the premise that a person who is lying has measurable physiological responses (heart rate, breathing, blood pressure and sweating) that differ from those of a person who is telling the truth but is under stress. It is certainly not the testimony of Mr. Tremblay, regardless of the fact that he may be an expert in operating the machine or analyzing the results, that will establish the soundness of this premise; indeed, on this point, the testimony of Mr. Tremblay is merely hearsay with no evidentiary weight.”

In Hydro-Québec v. Désaulniers, scientific evidence was submitted to the court.
Mr. Désaulniers called as a witness John Galianos whom the Honourable Judge Fréchette recognized as an “expert polygraphist witness.”
In his judgment of close to 150 pages, Mr. Justice Fréchette related almost all of the testimony (which certainly explains the length of the judgment). Among other things, he recounted the training which Mr. Galianos had undergone to become a polygraphist. The training consisted of a period of six (6) weeks spent in Chicago in 1976.
Answering the question of what purpose a test given by a polygraphist serves, Mr. Galianos testified as follows:


“To determine whether the person is telling the truth when relating his version of the facts. Using para-medical instruments, we record blood pressure, pulse, blood flow and reverse blood flow, changes in breathing and sweat gland activity.”

To satisfy the requirement of scientific or medical evidence imposed by Mr. Justice Dalphond in Vêtements Paul Allaire,5 the defendant, Désaulniers, called as a witness Doctor François Jolicœur, the holder of a masters in psychology and a diploma in psychophysiology. Doctor Jolicœur testified as to the physiological responses of an individual based on the individual’s psyche, in order to explain an individual’s state when telling the truth.
To counter this evidence, the lawyer for Hydro-Québec called as a witness Mr. François Lepore, a professor in the department of psychology at Université de Montréal. By contesting the soundness of Mr. Jolicœur’s testimony, the counter-evidence tended to show that polygraphs are not very useful. Mr. Lepore contested the literature cited by the adverse party, adding: [translation] “The research is often carried out by people who have an interest in such research being fruitful."

In summary, this witness did not agree that a physical reaction could be clearly influenced by a person’s psyche to such an extent as to allow one to detect a truth or a lie.

Judges decide the value of proof

Mr. Justice Fréchette’s ruling on the matter of polygraphs was very brief.

He dismissed this means of proof on the following grounds:

First, [Translation] “one must realize that, to date, polygraphs have not attained the status of pure science whose results would be as categorical as the answer to a mathematical operation.

Second, [Translation] “there is a fundamental rule of law regarding credibility which holds that the discretion to determine credibility lies with the courts.”

To support this conclusion, he referred to Professor Léo Ducharme’s work entitled Précis de la preuve (a work which nevertheless dates back to 1986), of which he cited the following passage, among others:


“But, as our courts have indicated, this is not a matter on which expert opinion may be heard, given that it is the exclusive role of the court to determine the truthfulness of a person’s statements.”

However, more recently, in his work Preuve civile, 3d Edition (2003), Professor Jean-Claude Royer stated the following:


“However, since the introduction of Article 2871 C.C.Q., Québec courts have admitted the results of lie detector tests, although, at times, they have given such evidence little probative value.”

He cited a series of judgments, including Hôtel Central (Victoriaville) inc.;6 however, this is merely an interlocutory judgment which provides no ruling on the merits as regards the probative value of a polygraph test.

Decisions on the merits regarding the admissibility of polygraph tests are rare.

Another recent decision, one rendered by the Court of Appeal in Brès v. Compagnie d’assurance générale Cumis,7 rejected such evidence.

Mr. Brès had refused to submit to a polygraph test. The trial judge had held this against him and had assimilated his refusal to a lie. The Court of Appeal reversed this decision and discussed the scientific value of polygraph tests:


“In general, the courts have been reluctant to use lie detectors for the following reasons: (1) their questionable degree of reliability; (2) the applicable rules of evidence; and (3) the fact that such a process cannot be substituted for the judge’s function of assessing the evidence, in general, and the credibility of witnesses, in particular.”8

The futur of the polygraph

 How can an insurer use a polygraph test if the person asked to submit to the test accepts? Besides the intimidation resulting from the test itself, it would seem that only confessions obtained before or after the test could, at the very most, be introduced into evidence. And even here, the issue of voluntary confessions arises: it might be difficult to introduce such a confession into evidence if the person having made it later retracts the confession on the very basis of the atmosphere surrounding the polygraph test when the confession was made.
The use of a polygraph test can certainly allow an insurer to complete its investigation or, to the extent possible, allow a claimant to support his sincerity and credibility. However, until the requirements set out by Mr. Justice Dalphond have been satisfied, it is doubtful that a court will accept such evidence in the future, even if the evidence is accompanied by a video tape showing the entire polygraph test process.


[1] [1984] C.S. 671.  
[2] J.E. 98-1363.  
[3] The Honourable Pierre Dalphond, then of the Superior Court, June 27, 2000, 540-05-000928-956.  
[4] The Honourable Jean-François De Grandpré, May 23, 2001, 700-05-006586-980.  
[5] See note 3.  
[6] See note 2.  
[7] (2004) R.R.A. 318.
[8] R. v. Béland, [1987] 2 S.C.R. 398.

This bulletin provides general comments on recent developments in the law. It does not constitute and should not be viewed as legal advice. No legal action should be taken on the basis of the information contained herein.



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