Can You Really Smell Fear?

Have you ever heard the phrase that you can smell fear? While this may seem like a colloquial phrase or an exaggeration, science shows that there is, in fact, a connection between fear and scent. This intersection of the psychological and the physiological is something that most of us — unconsciously — experience every day, and researchers have gotten a lot closer to finding an answer as to how — and why — this phenomenon occurs.

How Humans Smell Fear

Fear is one of the most primal and powerful emotions we possess. When our bodies encounter panic, we release adrenaline, causing various changes in the body. It's in this heightened state that the body releases specific chemicals through sweat, and, remarkably, these chemicals carry a scent encoded explicitly as a “fear signifier,” which is different from typical body odor. While most of us are unaware of this scent, smelling fear shows us that it’s nearly impossible to hide our emotions.

Psychology Today recently documented this phenomenon, which had participants watch fear-inducing videos while wearing pads under their armpits to collect sweat. When the samples were presented to a different group, the participants could differentiate between fear-induced and non-fearful sweat based on scent alone.

Other Emotions Smell, Too

Many other emotions, such as happiness and sadness, also carry an olfactory component that aids in subconscious communication between two humans known as “chemosignals.” This ability to emit hormonal responses through our scent — and, in return, interpret others’ emotions — is believed to be an evolutionary holdover from our ancestors when language wasn’t developed enough to understand one another on a deeper, personal level. It also starts at birth — babies are instantly drawn to the smell of their mother’s skin — and continues for our entire lives. For example, in adults, men’s testosterone levels rise when they smell a woman who is ovulating. 

We also see this throughout the animal kingdom, which supports the idea that “smelling fear” is a vestigial trait at the base of our evolutionary brand. For example, dogs are some of the best “smellers” in the animal kingdom, being able to sniff out cancer cells and emotional changes in their human companions. While scientific evidence regarding their ability to specifically smell fear in humans remains inconclusive, research does point to a connection between canine responses and changes in owners’ moods that are only found at the molecular level. Whether it's fear, joy, or sorrow, our canine confidantes seem to possess an uncanny ability to sniff out our moods.

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