A new study suggests that maybe you really can smell human emotion.
Researchers at Utrecht University in the Netherlands found that it's possible for people to "smell" emotions like fear or disgust through excreted chemical signals. In turn, smelling those chemosignals provokes the same sort of emotional response: Smelling "fear" chemosignals provokes a facial expression indicative of fear, for example.
For the study, published in the journal Psychological Science, researchers had male study participants watch movies that either induced feelings of fear, or feelings of disgust. For the two days before the movie watching, the participants were instructed to be very careful about smell contamination -- meaning they couldn't eat smelly foods, drink alcohol, smoke, exercise a lot or use their own hygiene or detergents (they had to use odor-free ones provided for the study).
After the male study participants watched the fear- or disgust-inducing movies, the researchers gathered samples of sweat from them. Then, researchers gathered female study participants to do a visual task, all while being exposed to the men's sweat samples. As they did the task, their facial expressions and eye movements were monitored.
Researchers found that the women's facial expressions and eye movements were indicative of the kind of sweat sample that they smelled -- when they smelled the sweat taken from men watching the fear-inducing movie, they produced facial expressions indicative of fear. And likewise for the women who smelled the sweat from the men who watched the disgust-inducing movie.
This is not the first time it's been shown that it's possible to smell the emotions of other people. A study presented at the Association for Psychological Science meeting in 2010 by Rice University researchers found that people in a close romantic relationship are able to smell emotions like fear, happiness and sexual arousal in each other, Science News reported.
"Familiarity with a partner enhances detection of emotional cues in that person’s smell," study researcher Denise Chen, a psychologist at Rice University, told Science News.