The Knowing Nose: Chemosignals Communicate Human Emotions

Many animal species transmit information via chemical signals, but the extent to which these chemosignals play a role in human communication is unclear. In a new study published in Psychological Science, a journal of the Association for Psychological Science, researcher Gün Semin and colleagues from Utrecht University in the Netherlands investigate whether we humans might actually be able to communicate our emotional states to each other through chemical signals.

Existing research suggests that emotional expressions are multi-taskers, serving more than one function. Fear signals, for example, not only help to warn others about environmental danger, they are also associated with behaviors that confer a survival advantage through sensory acquisition. Research has shown that taking on a fearful expression (i.e., opening the eyes) leads us to breathe in more through our noses, enhances our perception, and accelerates our eye movements so that we can spot potentially dangerous targets more quickly. Disgust signals, on the other hand, warn others to avoid potentially noxious chemicals and are associated with sensory rejection, causing us to lower our eyebrows and wrinkle our noses.

Semin and colleagues wanted to build on this research to examine the role of chemosignals in social communication. They hypothesized that chemicals in bodily secretions, such as sweat, would activate similar processes in both the sender and receiver, establishing an emotional synchrony of sorts. Specifically, people who inhaled chemosignals associated with fear would themselves make a fear expression and show signs of sensory acquisition, while people who inhaled chemosignals associated with disgust would make an expression of disgust and show signs of sensory rejection.