Our body also responds to impersonal touches

Increased temperature in the face indicates unconscious arousal

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Even an impersonal touch by another person makes us hot in the truest sense of the word: the facial skin warms up measurably, indicating an unconscious bodily reaction. British researchers have found this out in an experiment. In this case, they briefly touched the skin of female subjects in various places with a supposed skin test device. Meanwhile, an infrared camera recorded the temperature changes in the face of the subjects. In response to the touch, the women's skin warmed to the forehead, mouth and nose. The result shows that skin contact causes even physical reactions, if it takes place in a less emotional context such as a laboratory situation, the researchers report in the journal "Biology Letters" of the British Royal Society.

It has long been known that sexual or emotional arousal causes physical reactions that also alter the skin temperature of a person: "For example, anxiety causes a rapid warming around the eyes while the temperature of the cheeks decreases slightly, " explain Amanda Hahn and her colleagues the University of St Andrews. Sexual arousal, however, increase the circulation of the facial skin, especially on the forehead and in the mouth area. It was unclear, however, whether even simple touches in everyday situations without accompanying emotions can cause such a reaction.

Skin test pretended

To test how the body and the unconscious react to non-emotional touches, the researchers resorted to a trick: they pretended to their 39 test subjects, they would examine their skin health with a novel device. An experimenter - male, female - touched the skin of women's hands, arms, sternum and face briefly with a small, glowing device.

The result: Especially with touches on the breastbone and on the face - rather more intimate parts of the body - the face temperature of the subjects increased significantly, as the researchers report. This effect was particularly strong when the experimenter was male. "These thermal changes show that even social touches provoke an excitatory response, and that it's stronger when we interact with the opposite sex, " says Hahn. Although the experiments were initially conducted only with women, but Hahn considers it very likely that men show the same reactions. For in other experiments on the thermal reaction both sexes would have reacted similarly.

Unconscious signals could act as social key stimuli

Whether this unconscious physical reaction can also be perceived by the respective counterpart is still unclear at the moment, the researchers say. However, it is quite possible, because the wetter skin is better supplied with blood. This could be manifested in subtle changes in skin color, such as a mild flush. display

"The changes in skin temperature could thus definitely act as a social key stimulus that signal subliminal feelings to the observer, " says Hahn. This could change their behavior and, for example, influence how attractively two people find each other. Whether this really is the case must now be further investigated. (doi: 10.1098 / rsbl.2012.0338)

(Biology Letters, 30.05.2012 - NPO)