New Thermography Tech Catches Liars Using "Pinocchio Effect" - More Accurate than Polygraph

Two thermal images corresponding to the beginning and the end of the lie: the decrease in the temperature of nose and hands and the increase in the temperature of the forehead are noticeable

Credit: University of Granada

Emilio Gómez Milán, lead researcher of this study, points out that the two facial regions key for measuring this ‘Pinocchio Effect’ are the forehead and the tip of the nose. “When we lie, the temperature of the tip of the nose decreases between 0.6 ºC and 1.2 ºC, while that of the forehead increases between 0.6 ºC and 1.5 ºC. The greater the difference in temperature between both facial regions, the more likely the person is lying,” the expert points out.

The reason for this phenomenon to occur is quite simple. When someone lies, the body experiences an emotional response, anxiety, which is revealed in the temperature of the nose. “Besides, a cognitive response also occurs since, for lying, we have to think, to plan our excuses, to analyze the context…, and that causes a cognitive charge in us, a strong demand for attentional control which translates into an increase in the temperature of the forehead,” Gómez Milán explains.

One of the subjects participating in the study makes a phone call lying to the person at the other end of the line. In the thermal image, the temperature of the nose has decreased while that of the forehead has increased

Credit: University of Granada

In other words, according to the author, “one has to think in order to lie, which rises the temperature of the forehead; but at the same time we feel anxious, which lowers the temperature of the nose.”

The UGR researcher warns that it is necessary to differentiate between the study of lying in a laboratory and in real life. “The methods we use in the laboratory are very different of those used, for example, by the Police, which uses the so‑called strategic interviewing (with questionnaires including ‘tricky’ questions and demanding a lot of details) to try and catch a liar.” True detection of lies, even carried out by professionals, is only slightly higher than pure chance (54%), and the rate rises to 60%‑70% with strategic interviewing.Its use in airports and refugee camps

“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. 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,” Gómez Milán says.

In order to carry out this study, published in theJournal of Investigative Psychology and Offender Profiling, the researchers worked with a sample of 60 Psychology students from the University of Granada, who underwent a series of tasks with the thermographer.

One of those tasks was to make a telephone call of about 3 to 4 minutes to a close person (partner, mother, friend, etc.), in which they should tell a significant lie made up by themselves (e.g., that they saw a celebrity or that they had had a car accident).

On the other hand, the control group, also monitored by the thermal camera, would make a similar call, but telling to the person at the other end of the line what they were watching on the computer (that is, gross images of mutilated bodies and car accidents).

Emilio Gómez Milán, UGR researcher

Credit: University of Granada

“In both cases, the circumstances made them feel anxious, 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,” the researcher explains.

The author warns that, despite the fact that this new method for detecting lies is an improvement on existing ones, “there’s no method with an accuracy of 100%, since the difference between truth and lie is quantitative, not qualitative. However, 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.”

Contacts and sources:
University of Granada

Citation:   The Mental Nose and The Pinocchio Effect: Thermography, planning, anxiety and lies
Moliné, E. Dominguez, E. Salazar‐López, G. Gálvez‐García, J. Fernández‐Gómez, J. De la Fuente, O. Iborra, F.J. Tornay, E. Gómez Milán
Journal of Investigative Psychology and Offender Profiling, Volumen 15, Issue 2, 2018.
DOI: https://doi.org/10.1002/jip.1505   .

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