The reverse Pinocchio effect: Your nose actually SHRINKS when you lie because its temperature drops

  • Scientists showed the temperature of your nose lowers when you tell a lie
  • This causes it to shrink - though the change is imperceptible to the human eye 
  • The team designed a lie detector test that tracks the temperature of your face
  • It picked out fibbers with an accuracy rate of 80 per cent 

Pinocchio tells the story of a wooden boy whose nose grew when he lied, but in reality the opposite is true - for 'real boys' at least.

Scientists have shown that your nose actually shrinks when you tell porkies because its temperature drops.

They designed a lie detector test that tracked the temperature of people's noses and say it picked out fibbers with 80 per cent accuracy.

The test is the 'world's most reliable lie detector' - 10 per cent more accurate than the famous polygraph test, researchers claim.

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Experts showed that your nose cools down when you lie. They developed a lie detector test that uses thermography to track whether people were telling porkies. Pictured is a participant before (left) and after (right) they told a lie. Red regions are hotter than orange and yellow

Experts showed that your nose cools down when you lie. They developed a lie detector test that uses thermography to track whether people were telling porkies. Pictured is a participant before (left) and after (right) they told a lie. Red regions are hotter than orange and yellow

Scientists at the University of Granada investigated the so-called 'Pinocchio effect'.

When we lie, the temperature of the tip of the nose drops up to 1.2C (2.16F), while the forehead heats up up to 1.5C (2.7F).

The greater the difference in temperature between both facial regions, the more likely the person is lying.

This strange reaction is triggered by the brain power we exert when telling a lie, as well as an anxiety we'll be found out.

'One has to think in order to lie, which rises the temperature of the forehead,' said study lead author Dr Emilio Gómez Milán.

'At the same time we feel anxious, which lowers the temperature of the nose.'

The phenomenon causes your nose to shrink slightly - though the difference is imperceptible to the human eye.

Researchers asked 60 students to complete a number of tasks while they were scanned by thermal imaging technology. 

One task saw participants make a phone call of about 3 to 4 minutes to a partner, parent or close friend in which told a significant lie.

Test subjects made up the lie by themselves, for instance that they saw a celebrity or that they had been in a car accident.

The lie detector test tracked the temperature of people's noses and was able to pick lies from the truth with an accuracy of 80 per cent

The lie detector test tracked the temperature of people's noses and was able to pick lies from the truth with an accuracy of 80 per cent

A control group, also monitored by thermal camera, made a similar call told the recipient what they were watching on the computer - distressing videos that showed mutilated bodies and car accidents.

'In both cases, the circumstances made them feel anxious,' Dr Gómez Milán said.

But the experimental group experienced the so‑called 'Pinocchio Effect' in the nose and the effect of 'mental effort' in the forehead, which allowed us to monitor the lie.'

He said the temperature change was picked up in 80 per cent of the liars - an accuracy rate better than any modern lie detector.

'With this method we have achieved to increase accuracy and reduce the occurrence of "false positives", something that is frequent with other methods such as the polygraph,' he said.

Dr Gómez Milán said police interviewers could one day combine current methods with images from a thermal camera to help catch lying criminals.

'The ideal case would be to combine both methods, strategic interviewing and thermography, moving our system to, for example, police stations, airports or refugee camps,' he said.

'That way, it would be possible to detect if a criminal is lying or to know the true intentions of people trying to cross the border between two countries.'

WHAT ARE THE NINE WAYS TO SPOT A LIAR?

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 more someone gesticulates, the more likely it is they might be fibbing (stock image)

The more someone gesticulates, the more likely it is they might be fibbing (stock image)

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.

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