It's a popular misconception that dogs will chase after a person who fears them. A dog would rather avoid someone emitting fear chemicals, as described in the article below.
Learn how a dog's nose allows them to pick up on chemical changes in our bodies and how they combine this with other sensory information to determine our mood.
Can Dogs Smell Fear?
Dogs have an incredible sense of smell possessing around 200 million scent receptors (in comparison, humans have about six million), leading many people to question what this heightened sense of smell does for them.
In a 2017 piece by the New York Times, one columnist wrote that, in theory, a chemist could isolate the sweat of a scared person and test a dog's reaction to it, though no such research had been done at that time.
So, the following year a bunch of researchers decided to challenge that premise and conducted a study that would determine a dog's reaction when exposed to the sweat of people who were feeling happy or scared.
This research demonstrated that dogs react differently to the human emotions of happiness and fear. While happiness promoted greater interaction between the dog and the stranger, fear made the dog less likely to approach the human. Instead, smelling fear increased the dog's heart rate and made them feel more stressed.
How Do Dogs Smell Fear?
Smell is the primary sense that dogs use to understand the world around them, and it is thousands of times more acute than our own. While our nose may be able to detect a teaspoon of sugar that's been added to a cup of coffee, a dog could sense one teaspoon of sugar diluted in one million gallons of water (the equivalent of two Olympic-sized swimming pools).
Dogs can detect which part of the human body an odor derives from and use positive emotions to respond to the scent of a familiar person, so it's not too difficult to believe that they could also smell fear.
The study by Biagio D'Aniello and his team suggests that a sense of chemo signals may be released by the body, which allows for the communication of emotions between various species. Dogs can detect these chemicals thanks to Jacobson's organ. This unique organ, located in the dog's nasal passage, allows them to detect chemicals, pheromones, and other scents which are undetectable to humans.
How Do Dogs Use Their Extraordinary Sense of Smell?
Dogs quite literally "see" the world through their noses, and they can detect more than human emotions with this incredibly powerful organ. Dogs use their nostrils independently to detect exactly what a smell is and where it's coming from. Unlike humans, they exhale through a different part of their nose, allowing them to perceive smells more clearly.
Once a dog receives a scent, it transmits signals to its brain to understand precisely what these scents mean. As these signals travel, they reach the olfactory bulb, an area of neural tissue responsible for processing scents. What's impressive is that a dog's olfactory bulb is 40 times larger than a human's when compared in relative size.
Thanks to this super sense, dogs can track drugs, explosives, or missing people; they can detect "invisible" illnesses such as post-traumatic stress disorder or early-stage cancer, and they are even helping to fight the COVID-19 pandemic.
Can Dogs Distinguish Between Fear and Other Emotions?
Dogs can indeed smell fear and other human emotions, but they combine these scents with various clues to differentiate between an array of human feelings.
Like people, dogs have five senses - smell, hearing, sight, taste, and touch - and they can use a combination of these to decipher a person's mood. Using your posture, gestures, voice tone, and body language, dogs can better determine how you are feeling.
These canines can help you recognize your emotional states much better; if your dog is in tune with your emotions, they can signal you that you have oncoming stress and anxiety and help you work through it more effectively.
How Do Dogs Respond to Fear?
People experiencing cynophobia may believe that no matter how calmly they act, a dog will sense fear in them and start to behave aggressively. This exacerbates the already existing dog fear and puts the person in a perpetual state of anxiety, so is there any truth to this belief?
In a study, researchers found that dogs are less likely to approach someone emitting the fear odor. Instead, they're more likely to stay close to their owners and avoid the stranger. So, what's really going on here?
Well, people who experience a fear of dogs are more likely to inadvertently engage in aggressive behaviors towards them, such as standing face on or looking them directly in the eyes. And these perceived aggressive behaviors cause a dog to react rather than the fear scent that the person transmits.
Dogs can smell fear, but they are very unlikely to react aggressively. To decrease tension, ensure you stand side-on, keep still, and avoid direct eye contact. A dog will be far more comfortable staying with its owner's familiar scent than chasing someone feeling scared.