Spill coffee on your pants during a presentation or get asked out on a date by the person you've always had a crush on, and your face might turn bright red. But a new study reveals that even far more subtle social interactions can raise our temperatures. Researchers used thermal imaging (pictured above) to track the face temperatures of 23 women while they spoke with an experimenter asking them neutral questions about their demographics. During all of the encounters, facial temperature increased by an average of 0.1°C. When the experimenter touched the subject's face or chest under the guise of using a device to test skin temperature, the participant's facial temperature rose more, by as much as 0.4°C. This is as much as the temperature change seen when someone is embarrassed or aroused, but in this case, the subjects reported none of these emotions. And when the participant was interacting with a male, the rises in temperature were more extreme than when the experimenter was a woman, the scientists report online today in Biology Letters. The study is the first to show that facial temperature rises even when someone isn't experiencing strong emotions. Among other applications, the findings may help scientists develop better lie detector tests, as fibbing has also been shown to raise the temperature of the face.
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