Have no shame: Sweat odor conveys positive emotions
The chemical compounds -- called chemosignals -- that we produce when we're happy are detectable by those who smell our sweat, according to a new study.
"This suggests that somebody who is happy will infuse others in their vicinity with happiness," says senior researcher GĂźn Semin of Utrecht University in the Netherlands. "In a way, happiness sweat is somewhat like smiling -- it is infectious."
In fact, previous studies have demonstrated that negative emotions related to fear and disgust could be communicated in the same way.
The research team set out to examine whether happy people's sweat would influence those around them by recruiting 12 Caucasian males who provided sweat samples.
Participants were non-smokers, were not taking medications and had not been diagnosed with psychological disorders.
Researchers forbid them from drinking alcohol, having sex, eating smelly foods or exercising excessively.
Presumably happy despite the restrictions, participants rinsed and dried their armpits, and researchers attached absorbent pads to each armpit.
Wearing a prewashed T-shirt, they were asked to watch a video intended to induce fear, happiness or a neutral emotional state.
Next, they were asked to view Chinese symbols and rate how pleasant or unpleasant they found each one in an assessment of implicit emotion, which demonstrated that their feelings corresponded with the film clip they had watched.
Sweat pads were then removed and placed into vials.
The second part of the study focused on women, for they are thought to have a better sense of smell and be more sensitive to emotional signals than men.
Working with 36 healthy Caucasian women, researchers conducted a double-blind exposure to the sweat samples previously conducted meaning neither participants nor researchers knew whose sweat a given woman was sniffing.
With a five-minute break between each odiferous experience, they were exposed to three sweat samples, each bearing one of the three emotional states induced in the men upon watching the video clip: Happy, scared or neutral.
A facial expression analysis revealed that those who sniffed fear sweat demonstrated tension in the medial frontalis muscle, a common condition of scared faces.
A Duchenne smile, characterized by a width so broad it makes the eyes crinkle, is well known to signify happiness and that's exactly what the women who had sniffed happy sweat demonstrated.
The women's facial responses did not correspond with their explicit ratings of how enjoyable they found the sweat odor.
Yet the findings suggest synchronization in behavior between the men who produced the sweat and the women who sniffed it.
The paper "A Sniff of Happiness" was published in the journal Psychological Science.
