Many animals are known to sense fear and other emotions. As it turns out, humans can smell fear in one another too. We can unconsciously identify stress or fear in our peers through the smell of a chemical pheromone released in sweat. Pheromones are chemicals secreted by an animal that can be picked up on by another animal of the same species.
“Humans can smell fear in one another too.”
Pheromones have become an evolutionary advantage for helping animals in the wild. When a European honey bee stings, it releases a mix of compounds, including isopentyl acetate. This chemical alerts other honey bees of danger. Additionally, a change in organic compounds coming from a human’s breath or sweat due to stress can be picked up by dogs, which makes them great emotional support and PTSD service animals.
The idea that humans can smell the pheromones associated with fear has been heavily debated by scientists, with many not believing it to be true. However, research conducted by Dr. Lilianne Mujica-Parodi seems to have proven that humans can, in fact, smell each other’s fear. Mujica-Parodi’s team gathered sweat from novice skydivers through absorbent pads taped to each skydiver before and while they jumped. As a control group, sweat was also collected from the same individuals while they ran on a treadmill. Next, volunteers in a brain scanner breathed in the sweat after it went through a nebulizer. In volunteers who breathed in the sweat of the skydivers the regions of the brain associated with fear, the amygdala and the hypothalamus, were much more active.
The ability to smell fear can impact our flight or fight reflexes, as well as our mental health. When exposed to the fear pheromone, anxiety is triggered. This is especially apparent when in busy crowds, as emotions can be contagious because of this finding.
Amphibians, reptiles, and mammals use the vomeronasal organ to detect pheromones, this is a group of sensory cells located in the nasal chamber. These cells can detect moisture-borne odor particles, such as pheromones. Scientists are still researching this area and how it relates to humans as the vomeronasal organ is not connected to the human brain, unlike other animals. So, the way in which humans identify the smell of fear is still up in the air.
The applications of fear pheromones in humans are rather interesting. There have been concerns of isolating the fear pheromone for use in warfare to induce terror. However, psychiatrist Simon Wessely at King’s College London stated that using this as a chemical weapon wouldn’t work since it would induce physiological symptoms of fear but that wouldn’t be enough to actually make people afraid.
While fear pheromones activate regions of our brain associated with terror, they are extremely impacted by context and in many cases the fear they actually induce can be considered minimal. As seen through animals in the wild, the ability to smell each other’s fear is a useful tool to keep individuals alert when exposed to potential threats. The smell of fear makes regions of our brain that are associated with terror more active, keeping us aware.
“As seen through animals in the wild, the ability to smell each other’s fear is a useful tool to keep individuals alert when exposed to potential threats.”
