How you smell makes a difference to those around you — a spritz of cologne could remind someone of an important memory and the scent of your hormones could be what attracts your next lover. Accordingly, if you walk through a haunted house and come out smelling particularly dank, your crew will know you’re lying when you say it was no big deal. The stench of fear attaches itself to you, whether you like it or not.
Increasing evidence shows that humans can still smell when someone is afraid, and researchers are on the hunt for the molecules in human sweat that actually correspond to fear and anxiety. They already know that body odor that emerges after a workout is a byproduct of apocrine gland sweat in an attempt to keep your body cool. The smell that emerges when you’re afraid, some scientists believe, is a way of telling people that there’s danger nearby.
“If you find yourself in a fearful situation you might want your cohorts to know about it, but without calling your attention to yourself by screaming or jumping around,” Charles Wysocki of the Monell Chemical Senses Center told Popular Science.
In 2009, Rice University psychologist Denise Chen and her team tested whether smell could affect emotion perception in humans, much like it does with animals. To test this, they collected sweat samples of male volunteers after they were shown frightening films. Next, they exposed female volunteers to chemicals derived from this “fear sweat” while showing them images of happy, ambiguous, and fearful faces. The smell captured when the men were scared, Chen believes, led the majority of women in the study to interpret the ambiguous faces as fearful. This, she writes, provides “direct behavioral evidence that human sweat contains emotional meanings” and demonstrates that “social smells modulate vision in an emotion-specific way.”
A similar experiment was conducted in 2012 by researchers from the Netherlands. In this study, researchers showed ten men films that induced fear or disgust, then collected and froze their sweat samples. They then had a sample of 36 women complete visual tasks while being exposed to either fear sweat or “disgust sweat.” The sweat samples caused the women’s facial expressions to match the emotion of the men who gave the sample; for example, when they smelled a man’s fear, they too looked afraid. This signaled to the researchers that humans can communicate through unconscious “emotional synchrony” via chemosignals.
Smelling of fear may have helped our evolutionary ancestors survive, but whether it’s still useful now is up for debate. If you’re an ancient hominid whose scent could warn your tribe that there’s a predator nearby, the smell of fear could very well be a blessing. But if you’re a modern-day human on a date to see Oujia: Origin of Evil — not so much. Regardless, a fearful human is going to be a smelly one.