A new study has identified a “Pinocchio effect” that can be used to tell if a person is lying. Though the nose of fibbers doesn’t actually grow, the temperature rises around the nose and the orbital muscle in the inner corner of the eye. This could allow someone with a thermographic camera to identify liars.

The researchers stated that thermography, a technique that uses body temperature to detect changes in the body, can be used to identify a wide range of mental states. Changes in temperature are associated with the physical, mental, and emotional status of a person. Psychologists in the Department of Experimental Psychology at the University of Granada used thermography to determine the temperature changes in humans who are thinking hard, lying, exercising, or sexually excited.

Different types of exercise have different types of thermal “footprints.” This was demonstrated in the study by different types of dance.

“When a person is dancing flamenco the temperature in their buttocks drops and increases in their forearms. That is the thermal footprint of flamenco, and each dance modality has a specific thermal footprint,” said the study’s authors.

When thinking hard or expending significant mental effort, the temperature of the face was shown to drop. This contrasts with the emotional state of anxiety (such as lying), which raises the temperature of the face. The Granada researchers stated that an area of the brain called the “insula” is also activated when lying. The insula is involved in both the regulation of body temperature and the brain reward system. It only activates when “real” feelings are experienced, and the more active the insula is, the lower the temperature change is.

As for sexual excitement, the researchers stated that chest and genital temperature increases were observed in both men and women. The study claims to show that men and women get excited at the same time, even when women say they are not excited, or are only slightly excited.

(Image courtesy the University of Granada)