10 December 2012

The nose knows: Pinocchio effect reveals liars

by Will Parker

Applying thermography techniques to the field of psychology, Spanish scientists have observed the "Pinocchio effect," where a person's nose becomes warmer when they are lying. The researchers, from the University of Granada, also found that our face temperature drops when we are performing challenging mental tasks.

Thermography was developed in the USA during World War II to detect enemy movement at night and, now, researchers Emilio Gómez Milán and Elvira Salazar López are pioneering its use in measuring physiological changes under a variety of stimuli.

Salazar said that when we lie, the temperature around our nose rises and a part of the brain known as the insula is activated. The insula is a component of the brain reward system, and it only activates when we are experiencing "real" feelings. The insula is also involved in the detection and regulation of body temperature and there is a strong negative correlation between insula activity and temperature increase. "The more active the insula [the more real the feeling] the lower the temperature change, and vice versa," she explained.

Salazar added that sexual excitement and desire can also be identified using thermography. "They induce an increase in chest and genital temperature. Our study demonstrates that - in physiological terms - men and women get excited at the same time, even although women say they are not excited or only slightly excited," she noted. The researchers also demonstrated that thermography can be used to measure empathic states. Salazar said that in experiments where a subject received an electric shock to the arm, an empathic observer would experience a rise in temperature in their arm.

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Source: University of Granada