liegen (gezicht)

Want to know whether someone is lying to you? Just look at the person’s eyebrows and lips, they can give you the answer, scientists say.

A team from the University of British Columbia in Canada claimed to have identified four facial muscles that can “leak” a person’s true feelings like guilt, amid intense emotional pressures.

While liars were betrayed by tiny movements that caused them to raise their eyebrows in surprised expressions and smile slightly, innocent people tended to furrow their brow in genuine “expressions of distress”, the researchers found.

A person’s lack of control over their facial expressions meant genuine feelings could be differentiated from fake emotion, they said. Most humans, according to them, can control lower face muscles to talk or eat but those in the upper face are difficult to manipulate and can spark involuntary behaviour.

“Our research suggests that muscles of the face are not under complete conscious control and certain muscles are likely to betray the liar, particularly in high-stakes and highly emotional situations,” Dr Leanne ten Brinke, who led the study, told The Daily Telegraph.  “Facial cues are an important, but often ignored, aspect of credibility assessments where an emotional issue is in question,” she said.  “Cues to emotional deception are likely to occur when the underlying emotion a liar is attempting to mask, is relatively strong.”

In the study, published in the journal Evolution and Human Behaviour ( april ’12), the researchers analysed facial expressions of a group of people — half of whom were later proved to be lying — as they made emotional televised pleas for the safe return of a missing relative.  They found that deceptive pleaders raised their forehead muscles, called the frontalis, which gave off surprised expressions.

Liars also had increased activity of the “zygomatic majormuscles”, located around the mouth, which caused them to inadvertently lift their lips into a smile, found the team that also viewed over 23,000 frames of video from real-life cases in Britain, America, Canada and Australia.

Dr ten Brinke, from the university’s Centre for the Advancement of Psychological Science and Law (CAPSL), said the study found muscles “leaked” signs of true emotion because of the person’s subconscious actions.

This compared to “genuine pleaders”, who activated their inner frontalis and “corrugator supercilli”, located between the eyebrows, which caused them to frown and furrow their brow in a genuine “an expression of distress. While genuine pleaders show real distress on their face, the deceptive pleaders are unable to replicate that same activation,” Dr ten Brinke said. While the findings were important for “lie catchers”, she cautioned they did not provide a “Pinocchio’s nose”.

“Not everyone will leak their true emotions, and some people are better than others at adopting a false face (such as) psychopaths,” she added.