The conventional wisdom of the twitchy nervous liar who touch his nose and play with his hair is bunk.
Samantha Mann and colleagues monitored 130 volunteers as they were asked to lie - she found that liars actually tended to stay still as they were aware that their body language might be giving them away!
She added: "People expect liars to be nervous and shifty and to fidget more, but our research shows that is not the case.
"People who are lying have to think harder, and when we think harder we tend to be a lot stiller, with fewer movements, because we are concentrating harder."
She added: "As soon as we know that we are lying we suddenly become very aware of our behaviour.
"Most people tend to refrain from making movements at all."