When threatened, many animals release chemicals as a warning signal to members of their own species, who in turn react to the signals and take action. Research by Rice University psychologist Denise Chen suggests a similar phenomenon occurs in humans. …
Exposure to the smell of fear biased women toward interpreting facial expressions as more fearful, but only when the expressions were ambiguous. It had no effect when the facial emotions were more discernable.
Chen’s conclusion is consistent with what’s been found with processing emotions in both the face and the voice. There, an emotion from one sense modulates how the same emotion is perceived in another sense, especially when the signal to the latter sense is ambiguous.
“Our findings provide direct behavioral evidence that human sweat contains emotional meanings,” Chen said. “They also demonstrate that social smells modulate vision in an emotion-specific way.”
Smell is a prevalent form of social communication in many animals, but its function in humans is enigmatic. Humans have highly developed senses of sight and hearing. Why do we still need olfaction? Findings by Chen and Zhou offer insight on this topic. “The sense of smell guides our social perception when the more-dominant senses are weak,” Chen said.