So some scientists wondered how much these chemosignals might play a role in emotional contagion among humans. In a 2012 study, one team of researchers designed an experiment to find out. In it, one set of participants watched videos that would provoke either fear or disgust, while wearing sweat pads in their armpits. Afterward, a second set of participants were asked to smell those sweat pads, and the experimenters recorded their emotional state. Conveniently, the emotions of fear and disgust tend to provoke opposite physical responses. When you’re scared, your body will typically try to take in more sensory information. So your face will open up as you breathe more deeply and scan the environment with your eyes. On the other hand, when you’re disgusted, you’ll generally reject sensory information. Like, you'll walk past a row of portapots and you'll scrunch up your face, take really shallow breaths, and look around less. Now, these reactions aren't always super visible to the eye, but by monitoring their eyes and facial movements, the researchers could tell which facial muscles were activated in each person, and which emotional state their expressions reflected. And the authors found that participants who sniffed disgust sweat tended to display disgust which, you know, seems like a normal reaction when you're sniffing sweat pads, but also, those who sniffed fear sweat would also display fear.