Body language experts have been having a field day since the U.S. presidential debate. They want us to believe that it’s possible to tell what Donald Trump and Kamala Harris are thinking, but not saying, just by looking at their body and facial movements.

As the election approaches, every move the candidates make will be “decoded” and broadcast in the media. But how good are these analyses?

For over 10 years now, I’ve been looking at the influence of beliefs on non-verbal communication, in the particular context of legal trials. My work has shown that when it comes to judges assessing the credibility of witnesses, some apply unsubstantiated beliefs, or beliefs that have been proven false. These beliefs can then lead them to disbelieve honest witnesses and to believe dishonest ones.

Read more: Regards fuyants, nervosité, hésitation... Comment le non-verbal peut influencer la justice, à tort

Non-verbal communication, i.e. communication by means other than words, has been the subject of thousands of scientific publications for decades now.

From the role of facial expressions in developing a bond of trust between doctors and patients, to the impact of gestures in public speaking and assessing the credibility of witnesses in trials, non-verbal communication is studied in a multitude of disciplines, including communications, psychology, criminology and computer science. Researchers around the world publish peer-reviewed articles on non-verbal communication.

Here are some of the findings that merit........

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