The image of a twitchy nervous liar touching his nose and stroking his hair may itself be a lie, a study says. Italian and British researchers found when people lied they tended to stay still as they were acutely aware their body language might give them away.

“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.”

Those under strong suspicion used certain types of hand gestures more in order reinforce the point. The use of metaphoric gestures – such as touching the heart to show love and or the holding of hands apart to indicate size – were used 25% more often when people lied.

Rhythmic gestures such as repeated pointing to emphasise statements were also used more often by liars.

Uh-huh.