Clearly, such tricks may already be used by some expert detectives – but given the folklore surrounding body language, it’s worth emphasising just how powerful

Clearly, such tricks may already be used by some expert detectives – but given the folklore surrounding body language, it’s worth emphasising just how powerful persuasion can be compared to the dubious science of body language. It strikes me to the degree that the folklore is mixed with the (so called dubious) science. I was always interested in the topic, and had indeed read a book when I was teenager, with ideas such as the iconic example of Clinton touching his nose. About 5 years ago I went to the topic again; learned that one of the biggest authority in the topic was Paul Ekman and read a couple of his books Surprise surprise, the main takeaways were ideas such as: (...) not to jump to early conclusions: just because someone looks nervous, or struggles to remember a crucial detail, does not mean they are guilty. Instead, you should be looking for more general inconsistencies. Or There is no fool-proof form of lie detection, but using a little tact, intelligence, and persuasion, you can hope that eventually, the truth will out. Ekman repeated all over the place that there is no body language for lies, only for emotions, and that the emotions can have a variety of causes. And that was already clear the last century! If some security entity has bought something that promised to spot lies, it was probably folklore-based and no science-based.