Even non-sexual social contact can raise body temperature

(Medical Xpress) -- Researchers at the University of St Andrews found that non-sexual social interactions with men caused a noticeable rise in the temperature of a woman's face, without them even noticing.

The research was conducted by Amanda Hahn, Carmen Lefevre and David Perrett from the University's Perception Lab. The team used thermal imaging to monitor temperature changes in women during interactions with a man or another woman.

The findings could be important for the development of thermal imaging in monitoring changes in levels of stress and emotion, for example in lie detection tests, where the merest increase in temperature would be picked up.

Lead author Amanda Hahn, explained, "We used a thermal camera to record skin temperature during a standard 'social interaction' where we measured participants' skin colour at 'non-personal' (i.e. the arm and palm of the hand) and 'personal' (i.e. the face and chest) locations on the body. The thermal response was dramatic when the male experimenter made contact at 'personal' locations."

While it may not be surprising that people have a physiological response to social contact, the size of the reaction was surprising. Hahn commented, "We observed some women whose facial temperature increased by an entire degree (Celsius) during interaction with the male experimenter.

"This thermal change was in response to simple social interaction, without any experimental change to emotion or arousal. Indeed our participants did not report feeling embarrassment or discomfort during the interaction."

The study, published later this month in Biology Letters, shows that gender alone influenced the reaction of women, who showed no response to interaction with other women.

Professor David Perrett, who runs the Perception Lab added, "This finding is interesting and important for future work. Thermal imaging is a relatively new technique employed to monitor emotion and stress. We are only just beginning to understand the potential uses of thermal imaging in medicine and it can be very useful in areas of national security, where changes in skin temperature can be gauged as part of lie detection tests."

The research team’s next goal is to work out whether or not these physiological changes are detected by others and whether they affect social interactions. Study co-author Carmen Lefevre concluded, "We are currently exploring the link between changes in skin temperature and skin colour. A slight increase in blood flow may cause the skin temperature to rise; this increase in blood flow may also cause the skin to become redder. We do not yet know if these changes are evident to others or how they affect perceptions of attractiveness."