How we change what others think, feel, believe and do
Seven Facial Characteristics of Liars
Ekman (2003) describes seven facial characteristics that can be used to differentiate between voluntary (deceptive) and involuntary (natural) facial expressions. Here is a discussion of each.
When we express emotions, the face distorts and forms distinct shapes for each emotion, such as the smile of happiness or the sneer of contempt.
This is a complex activity involving clusters of many muscles. The natural smile, for example, uses around 20 muscles. Liars have problems managing all these and their expressions may seem somehow false. Watch particularly for the fake smile as liars try to cover their deception with friendliness.
Also watch for the blank stare as they try to hold their face still to avoid morphological errors. Particularly notice elements that cannot be controlled, such as pupil size in the eyes.
Natural expressions tend to be more symmetrical, while deliberate expressions are more asymmetrical.
This may be a small variation which is difficult to measure. It also varies with the person, for example where they have a natural lop-sided smile, so be careful and only use this as an adjunct to other indicators.
Natural expressions tend to be between about half a second and four seconds. Deliberate expressions may be very brief or very long.
Very brief, fleeting expressions (or micro-expressions) are a strong giveaway. Watch for flashes of the downturned mouth as the subconscious shows its disgust at the person telling lies. Also watch for the quick smug grin of duper's delight. Longer emotions, such as a smile that is held for too long are typical of forced, deliberate expression.
Watch carefully for micro-expressions and note fixed, longer expressions.
Natural emotions tend to appear smoothly and may even spread slowly, such as a gradual grin. Deliberate expressions tend to appear quickly, as if the person has suddenly remembered to smile or physically show other feelings.
Although it can vary greatly with social situations, watch for a delay between the words and the action of the expression as the person concentrates first on the words and then on the body language. Also notice how quickly the face goes from one expression to another.
In natural expressions when there are multiple independent facial actions, the most intense points of each expression will often overlap. Deceptive multiple expressions will be separated sequentially in time.
Expression of multiple, possibly interacting, emotions requires complex dynamic distortions of the face. This is quite common in emotional situations as we struggle with a mix of love, fear, anger and so on.
If it is hard for a liar to fake individual expressions, it is far harder to shape multiple simultaneous emotions. It takes a great actor to convincingly express such complex, intertwined feelings.
Watch also for sequential switching between multiple emotions rather than seeing them all interact as this can also indicate conscious thinking about expressions.
Facial expressions have a 'trajectory' of gradually appearing, peaking and fading. In natural expressions this will be a smooth process. In deliberate expression, it will be more jagged or offset, with more sudden changes.
As the brain experiences an emotion, it receives injections of neurotransmitters and hormones which build up and fade in a natural, smooth flow. This does not happen in the cognitive movement of deception.
Although natural emotions can appear quickly, they take more time to cool down and fade. Watch for other sharp changes in facial dynamics that seem unlike that which you would seen in a normal emotion.
In a natural expression of emotions, it will align closely with the words spoken and other expressed feelings. In a deceptive situation, expressions may be missing, too short, too long or out of step with the spoken words.
Lying is hard work! The liar has to think carefully about what to say as well as how to express it. It is no wonder that they easily fall out of step.
Watch for a discontinuous flow of words and expressions that do not fit easily together. Note pauses as the person tries to get it all together. Spot hurried added emotional expressions and inserted words that try to paper over the cracks. Beware of them trying to distract you from their inner confusion and exhaustion.
Watch for each of these variables when a person may be lying. if you see one or two transgressions, this may not mean much, but if you detect more of the seven characteristics then you may well have a liar on your hands. Note also where they lie to find out more about what exactly they are trying to cover up.
Ekman, P. (2003). Darwin, Deception, and Facial Expression, Annals of New York Academy of Sciences, 1000: 205–221