The respectability of polygraph evidence, at best, remains an open question, and any litigant seeking to invoke it for any legitimate purpose, must, needs be, adduce expert evidence of its conceptual cogency and the accuracy of its application in every given case.

The cardio-pneumo-psychograph and the thief

In the spring of 1921, a women’s-only private dorm at the University of California was rocked by a crime wave. It started small: silk undergarments, books, registered letters, items whose absence could be attributed to carelessness. On the night of 30 March 1921, Ethel McCutcheon, a sophomore from Bakersfield, returned to her room to find that her evening dresses had been removed from her closet and spread out on the bed. A textbook with $45 tucked inside had been taken and her bureau had been ransacked. McCutcheon was not the only victim that evening. Rita Benedict, a freshman from Lodi, had more than $100 in jewellery and cash go missing. Margaret Taylor, a first-year student from San Diego, could not find her diamond ring. She had no choice but to contact the police who decided to bring in John Larson, a college cop with a background in science, who, at the time, was building a strange device which the police hoped could help wrap up the case.

Police officer Jack Fisher decided to call in his colleague, John Larson, a 29-year-old with a doctorate in physiology who had joined the police force in search of real-world experience before embarking on a career in criminology. He had a device, the “cardio-pneumo-psychograph”, which Fisher suggested he should take to the dormitory and test all 90 residents. They all agreed – perhaps because refusing to be tested would have seemed like a clear indication of guilt.

Larson attached his machine to woman after woman, repeating his list of questions again and again. Then he came to Helen Graham who showed no emotion as Larson worked his way through the list of questions – until he got to ones about the missing money and jewellery. “Did you take Miss Taylor’s ring?” Larson asked. After she responded with a quick “no,” he glanced at the chart.

“The test shows you stole it,” he said flatly. The next day, Graham turned up at the police department, demanding to speak to Larson and asking to see the chart. Larson and a colleague then interrogated her for 12 hours while she continued to maintain her innocence. Eventually, though, she broke into “an attack of sobbing” and conceded that it was possible that she might have taken the items in her sleep. Graham finally admitted to taking the money and the ring as well as some items of clothing. In exchange for the confession, she wanted guaranteed immunity from prosecution and to avoid being named publicly.

The lie detector had solved its first case. As Larson’s work with the lie detector progressed, he tried to rule out external factors that might influence or even throw off the tests. He started to suspect that in some cases it might be the questioner and not the questions that elicited an emotional response. To test this theory, he asked Margaret Taylor to come back to the lab for a follow-up experiment. “I thought you’d told me that I had passed,” she said when she arrived. “Now what’s wrong?”

“Nothing,” he said. “But I’ve got a new question here that’s not on the list I first prepared.” Seating Taylor in front of the lie detector again, he went through the preamble of the experiment. Then he asked her to lie to him on purpose, and he tried to tell when she was doing it.

Larson had discovered during his experiments that short, basic queries were the best questions to ask. The one he had written down for Taylor could not have been more simple: “Do you love me?” She quickly said “no,” but Larson did not need a machine to tell that she was lying. For a moment, she looked across at the rookie detective, his eyes fixed on hers. Then her gaze flicked over to the rolling drums of the apparatus and the black paper that had opened a window to her heart. According to The San Francisco Examiner, “the wings of the ‘lie detector’ trembled, fluttered, waved a frantic SOS.” That story was published 16 months later, on the day of Larson and Taylor’s wedding. (https://www.wired.com/story/lie-detector-never-very-good-at-telling-truth/)

Convicting the innocent

After the naked body of 16-year-old Teresa Fusco had been discovered on 5 December 1984 in a wooded area of Lynnbrook, New York, the help of the polygraph was called in.

The cause of death was ligature strangulation and in the light of semen and sperm found on the victim’s vaginal swabs, it was believed she had been raped.

During March 1985, John Kogut was taken to the police headquarters for a polygraph examination which indicated that he was lying when he denied involvement in the victim’s murder. After being interrogated for about 18 hours and repeatedly being told that he had failed the polygraph, Kogut eventually signed a confession that had been handwritten by a detective. He was tried and convicted of rape and murder in March 1986.

However, new DNA evidence later showed that the semen found on the victim’s body was from another man. It took almost two decades for Kogut to win a retrial after a series of post-conviction DNA tests excluded him as the rapist and proved that the semen from the victim’s body had come from an unknown assailant.

After a three-month bench trial, John Kogut was found not guilty by Nassau County Judge Ort on December 21, 2005.

Place in the sun

Although polygraph tests are administered on suspects and are used by employers to determine whether an employee is lying, experts have advised against using such tests for any reason since the accuracy and reliability of their results have come into question. According to Leonard Saxe, a psychologist at Brandeis University, there is no unique physiological sign of deception. And there is also no evidence whatsoever that the things the polygraph measures – heart rate, blood pressure, sweating and breathing – are linked to whether you are telling the truth or not. Professor Tredoux, head of the Department of Psychology at UCT, is in agreement. He too is of the opinion that polygraph testing has not been scientifically shown to be a reliable, accurate and valid means of detecting deception.

Recently, yet another case involving polygraph testing came before the Metal and Engineering Industries Bargaining Council. In Endeto Engineering v MEIBC [2023] ZALCJHB 26 Mr Nkabinde, an employee of Endeto Engineering was charged with:

• Gross misconduct: Dishonesty in that you made a false accusation against the CEO of the Company (Mr Raymond Lovett) to the effect that Mr Lovett was watching you relieve yourself in the bathroom on the 31st of October 2019, and/or alternatively
• Gross misconduct: Breach of an agreement signed by yourself in that you refused to undergo a Polygraph Examination on the 18th of November 2019 despite agreeing to do so on the 4th of November 2019.

According to Mr Nkabinde, he had been using a stall in the bathroom when the owner of the business, Mr Lovett, peeked over the stall wall and looked at him while he was relieving himself. Mr Nkabinde’s union addressed an email to Mr Lovett that evening, calling for an apology concerning the incident. When an apology was not forthcoming, a formal grievance was lodged by Mr Nkabinde against Mr Lovett. The outcome of the grievance was that both parties must submit to polygraph testing.

Polygraph testing was arranged to take place on 18 November 2019. On 4 November 2019, Mr Nkabinde signed a “Consent to [Undergo] Polygraph Examinations As Part Of Grievance Enquiry”. The terms of the “consent” are as follows:

1. The parties agree that the employee shall undergo a polygraph examination on a date and time to be determined as part of an ongoing grievance investigation, where it has been determined that the Cautionary Rule applies.
2. The employee acknowledges that he/she has been placed in a position of trust within the company, as a result, the employee is required to always act in the best interest of the employer, and at all times be honest.
3. Refusal to undergo a polygraph test in any manner will constitute a breach in the trust relationship between yourself and the employer, and will result in the inference being drawn that the allegations made by the employee are untrue.
4. The employee agrees to undergo a polygraph test, where the employer is investigating any incident of the commission of fraud and/or theft and/or gross dishonesty and/or gross negligence in which the employee or others may be implicated.

Mr Lovett attended the polygraph testing and the outcome was that no deception was detected. Mr Nkabinde did not attend. Following the disciplinary hearing, Mr Nkabinde was dismissed whereafter he referred an unfair dismissal dispute to the Metal & Engineering Industries Bargaining Council. The arbitrator found that Mr Nkabinde’s dismissal was substantively unfair and awarded compensation.

Dissatisfied with the outcome, the employer brought a review application – its main concern was the arbitrator’s assessment of credibility, and his disregard of Mr Lovett’s polygraph test results.

Regarding the polygraph, the Labour Court pointed out that:

… the inclusion of clause 3, as set out above, in a document intended to be a consent to undergo polygraph testing is loaded and heavy-handed, to say the least. That the employee signed this consent is neither here nor there in the circumstances where clause 3, among others, is not only offensive to public policy, but also offends the principles of natural justice and the interest of justice.

Even if I were wrong on the reasonableness of the arbitrator’s assessment of credibility, having regard to the heavy-handed terms of the consent, Mr Nkabinde’s grievance being transformed into a disciplinary hearing against him, and the disproportionate reliance on the result of Mr Lovett’s polygraph test results, it is clear that dismissal was wholly unfair in these circumstances. After all, the grievance could not have simply concluded with polygraph testing and not have provided for further steps once this was done.

The Court referred to DHL Supply Chain (Pty) Ltd v De Beer NO and Others [2014] 9 BLLR 860 (LAC) where it was pointed out that:

These considerations beg the question about what a failed polygraph test really produces by way of usable information. Only the inference to be drawn from the failure of the test is useful as material to determine probabilities. In the absence of expert evidence to explain what that inference is, either generically, or within the bounds of the specific instance itself, and also to justify the explanation of what that is, there is nothing usable at all that might contribute to the probabilities. In this appeal, DHL’s consent form, signed by the two respondents, states that the test would indicate that the worker was either involved or not involved in the stock loss. That premise is questionable, and to belabour the point, required the kind of expert evidence mentioned above to render it worthy of consideration.

In summary, the respectability of polygraph evidence, at best, remains an open question, and any litigant seeking to invoke it for any legitimate purpose, must, needs be, adduce expert evidence of its conceptual cogency and the accuracy of its application in every given case.

It seems that there might be a place for polygraph tests in labour law matters – however, it seems not to be a very special place.

Written by Nicolene Erasmus, Director, Labour Guide