The smell of fear modulates our perception of threat in faces

This is kind of neat: Zhou and Chen collected gauze pads that had absorbed sweat from the armpit apocrine glands of men (because they sweat more) watching a horror movie or a happy or neutral movie. Women sniffed the extracted smells (versus neutral controls) while watching a face morph from happy to frightened (women have more sensitive sense of smell and sensitivity to emotional signals). The chemosignal of fearful sweat biased the women toward interpreting ambiguous expressions as more fearful, but had no effect when the facial emotion was more discernible. This shows that fear-related chemosignals modulate humans' visual emotion perception in an emotion-specific way