I want to detect lying during trials

Vincent Denault

Vincent Denault

Credit: Amélie Philibert - Benoît Gougeon

In 5 seconds

As part of his PhD, Vincent Denault explores why witnesses lie in court.

When a witness lies in court, the search for the truth is compromised, and this can result in a serious miscarriage of justice. My doctorate deals with this situation. In Canada, perjury is a criminal offence punishable by imprisonment.

Who lies? And in what ways do witnesses who lie actually do it? How do judges conclude that a witness has lied? And is that conclusion based on the witness’s body language? These are the questions that interest me and which I intend to probe.

My analysis will be based on written court judgments and on false testimonies which were recorded during trials and which led to charges of perjury. The aim of my research is to provide an overview of lying in court, from a communication perspective. The idea came to me after practicing law for six years and studying the effect of non-verbal behaviour of witnesses during trials.

Vincent Denault

To find out more

Thesis supervisor


  • Fonds de recherche du Québec – Société et culture


  • Delmas, H., et autres. «Évaluation de la crédibilité des témoins: l’influence des croyances», dans Puigelier, C., et C. Tijus (dir.). L’esprit au-delà du droit: pour un dialogue entre les sciences cognitives et le droit, Paris, Mare et Martin, 2016, pp. 205-224
  • Denault, V., et autres. «La synergologie, une lecture pseudoscientifique du langage corporel», Revue de psychoéducation, vol. 43, no 2, 2015, pp. 425-455
  • Denault, V. Communication non verbale et crédibilité des témoins, Montréal, Éditions Yvon Blais, 2015, 246 pp.
  • Denault, V. «Le polygraphe devant les tribunaux civils québécois: croyances, science et jurisprudence», Revue du Barreau, vol. 73, no 1, 2014, pp. 33-58

In the media


Interview by Mathieu-Robert Sauvé