The big pause: Lying is quite a complex process for the body and brain to deal with. First your brain produces the truth which it then has to suppress before inventing the lie and the performance of that lie.
This often leads to a longer pause than normal before answering, plus a verbal stalling technique like ‘Why do you ask that?’ rather than a direct and open response.
The eye dart: Humans have more eye expressions than any other animal and our eyes can give away if we’re trying to hide something.
When we look up to our left to think we’re often accessing recalled memory, but when our eyes roll up to our right we can be thinking more creatively. Also, the guilt of a lie often makes people use an eye contact cut-off gesture, such as looking down or away.
The lost breath: Bending the truth causes an instant stress response in most people, meaning the fight or flight mechanisms are activated.
The mouth dries, the body sweats more, the pulse rate quickens and the rhythm of the breathing changes to shorter, shallower breaths that can often be both seen and heard.
Overcompensating: A liar will often over-perform, both speaking and gesticulating too much in a bid to be more convincing. These over the top body language rituals can involve too much eye contact (often without blinking!) and over-emphatic gesticulation.
The poker face: Although some people prefer to employ the poker face, many assume less is more and almost shut down in terms of movement and eye contact when they’re being economical with the truth.
The face hide: When someone tells a lie they often suffer a strong desire to hide their face from their audience. This can lead to a partial cut-off gesture like the well-know nose touch or mouth-cover.
Self-comfort touches: The stress and discomfort of lying often produces gestures that are aimed at comforting the liar, such as rocking, hair-stroking or twiddling or playing with wedding rings. We all tend to use self-comfort gestures but this will increase dramatically when someone is fibbing.
Micro-gestures: These are very small gestures or facial expressions that can flash across the face so quickly they are difficult to see. Experts will often use filmed footage that is then slowed down to pick up on the true body language response emerging in the middle of the performed lie.
The best time to spot these in real life is to look for the facial expression that occurs after the liar has finished speaking. The mouth might skew or the eyes roll in an instant give-away.
Heckling hands: The hardest body parts to act with are the hands or feet and liars often struggle to keep them on-message while they lie.
When the gestures and the words are at odds it’s called incongruent gesticulation and it’s often the hands or feet that are telling the truth.