Our happy hour fact to amaze your drinking buddies with.

The odor of sweat can reveal when humans are fearful.

Researchers at Rice University had male volunteers keep gauze pads in their arm pits as they watched movie scenes that were known to inspire fear. Afterward, the same pads were fitted under the noses of female volunteers as they viewed a series of facial images, ranging from happy to ambiguous to fearful.

The sweaty pads didn't have any influence on the women's ability to identify the happy or scared faces, but they did lead the participants to identify the ambiguous faces as being afraid. "The sense of smell guides our social perception when the more dominant senses are weak," the study's author concluded.

Of course, while smelling fear is really interesting, it's not even half as fascinating as people volunteering to sniff armpit pads.

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