We all know the story of Pinocchio since we were children, the character created by the Florentine writer Carlo Collodi whose nose grew every time he lied, which left him completely uncovered by his father and creator, Geppetto. Well, in real life, logically our nose does not grow when we are wrong, but it does give us away in another way, since its temperature changes , according to the study just published by a group of researchers from the University of Granada (UGR) in the Journal of Investigative Psychology and Offender Profiling .
These scientists, who work at the Mind, Brain and Behavior Research Center (CIMCYC) of the UGR, have just designed the most accurate laboratory model that exists to date to find out whether an individual is lying or not. This system, which uses thermography – a technique that allows us to graphically record the temperatures of the different areas of the body – is based on the ‘Pinocchio Effect’, which indicates that when someone lies there are various thermal changes in their face : for example , the temperature of your nose drops, while that of your forehead rises.
This system would be more accurate than the polygraph – an instrument popularly known as a lie detector that measures the changes experienced by the cardiovascular system and the body’s reaction when we lie – and other neuroimaging techniques, such as functional magnetic resonance imaging (fMRI). – there are those who defend the use of the data obtained by fMRI to detect, in the legal field, if a person has lied. The reason is that thermography offers an accuracy level of up to 80 percent, “10 percent more than the polygraph,” they explain from the UGR through a press release.
Emilio Gómez Milan, principal investigator of this work, highlights that the nose and forehead are the two key facial regions to measure the ‘Pinocchio Effect’ . “When we lie, the temperature of the tip of the nose drops between 0.6 and 1.2 degrees Celsius, while that of the forehead rises between 0.6 and 1.5 degrees. The greater the difference in temperature change between the two regions of the face, the more likely that person is lying ”, says the expert.
What is this about? On those occasions when we lie, an emotional response is produced in our body, we feel anxiety, and this is manifested through the temperature of the nose . “But there is also a cognitive response, because to lie we have to think, plan our excuses, analyze the context …, and this causes us a cognitive load or a strong demand for attention control that translates into an increase in the temperature of the front ”, adds Gómez Milan.
To carry out this study, they started an experiment in which sixty psychology students from the UGR participated. Among the tests they had to make, a phone call to a loved one, lasting between three and four minutes, in which they had to tell a significant lie invented by them – for example, that they had just seen a famous person or who had suffered a traffic accident – while being monitored with a thermal camera. Instead, they asked the control group to make a similar call, but telling their interlocutor what they were seeing on the computer screen: very unpleasant images of mutilated bodies and car accidents. As the researcher explains, “in both cases, the circumstances caused them anxiety, but in the experimental group there was the so-called ‘Pinocchio Effect’ on the nose and the ‘mental effort’ effect on the forehead that allows us to monitor the lie.”
Its possible applications
The techniques that the investigators use in the laboratory to catch a liar are very different from those used by the Police , since they use strategic interviews, with trick questions and the request of numerous details.
“The ideal would be to combine both techniques, strategic interviews with thermography, transferring our method, for example, to a police station, airports or refugee camps, to know when a criminal is lying, or what is the real objective of the people who try to cross the borders between countries ”, says Gómez Milan.
The author of the study acknowledges that “there is no method that is one hundred percent correct (in detecting lies) because the difference between the truth and the lie is quantitative, not qualitative.” Of course, with this new system they have managed to increase accuracy “and reduce false positives , something common in methods such as the polygraph,” he concludes.
Images: University of Granada
