Study: Variation in the Smell of Our Sweat Can Convey Fear or Disgust

Lindsay Abrams Nov 7 2012, 10:02 AM ET

Subjects were able to communicate emotions to one another using only perspiration.

Public Domain Photos/Flickr

PROBLEM: Some animals can communicate their emotional states through chemical signals called chemosignals. Can human animals do so as well?

METHODOLOGY: Researcher Gün Semin and company at Utrecht University in the Netherlands induced strong feelings in their subjects by showing them fear- or disgust-inducing films, then collected and froze their armpit sweat . The 10 male "sweat donors" had been decontaminated in the days leading up to the experiment by avoiding smoking, exercise, strong-smelling foods, and alcohol. The researchers then exposed their 36 female subjects -- all of whom met the threshold for having a normal sense of smell -- to the men's defrosted, fear or disgust-containing perspiration. The women's facial expressions and eye movements were carefully monitored as they completed a visual search task.

Worth noting: The women, who were tasked with smelling the men's sweat, were paid less than half of what the men received for their participation. A wage gap.

RESULTS: To a significant extent, receivers produced the same "facial-muscle configuration" made by the senders: The women who had been exposed to "fear sweat" reflected that fear in their faces, while those exposed to "disgust sweat" displayed facial expressions indicating revulsion.

The women's eye movements also varied depending on which stimuli they encountered. Those exposed to fear sweat displayed "sensory acquisition," their eyes widenly and moving more rapidly in accordance with the way those who are in danger need to be more aware of their environment. The others exhibited behaviors of "sensory rejection," lowering their eyes in a disgusted response.

CONCLUSION: Humans communicate in ways that aren't verbal or visual, unconsciously achieving "emotional synchrony" through the actions of chemosignals.

IMPLICATIONS: Our emotions (potentially including others like happiness and anger, that have yet to be studied) have transmittable biomarkers. The authors suggest that this may be part of the mechanism behind emotional contagion, wherein people "catch" the feelings of others.

The full study, "Chemosignals Communicate Human Signals" is published in the journal Psychological Science.