The Smells Of Human Stress Can Impact The Emotional State Of Our Dogs, Making Them More Cautious And Pessimistic

Seventyfour - stock.adobe.com - illustrative purposes only, not the actual dog
Seventyfour - stock.adobe.com - illustrative purposes only, not the actual dog

Dogs are very in tune with the emotions of humans. They know when we are happy, sad, or even stressed. But how do they know? What kind of canine superpower is this?

Researchers from the University of Bristol in England may have found the answer—and it’s through their powerful sense of smell. In the first study of its kind, the researchers tested how the odors of human stress affect the emotional state of dogs.

Evidence suggests that humans subconsciously react to the smell of a stressed person. Dr. Nicola Rooney, senior lecturer in wildlife and conservation at Bristol Veterinary School, and her team set out to explore whether dogs do the same.

They recruited 18 dog-owner partnerships to participate in a series of trials. During the trials, the dogs were trained to associate the location of a food bowl with the presence or absence of a treat. Once they learned the arrangement, they were faster to approach the bowl with a treat than an empty one.

Then, the researchers switched it up by placing bowls in new, ambiguous locations between the two original bowls. If the dogs approached the bowls in the ambiguous locations quickly, that meant they were “optimistic” about the presence of food—a sign of a positive emotional state.

On the other hand, if they approached slowly, that indicated “pessimism” and a negative emotional state.

Each dog was also exposed to no odor or the odors of human stress, which were sweat and breath samples that were taken after an arithmetic test.

The researchers discovered that when the dogs were exposed to the smell of stress, they became slower to approach the ambiguous bowl location nearest the empty bowl location.

The “pessimistic” response was not seen when dogs were exposed to relaxed smells, which were samples from humans listening to calming soundscapes.

Seventyfour – stock.adobe.com – illustrative purposes only, not the actual dog

These findings suggest that the smell of human stress affected the dogs’ decisions and expectations.

The stress smell may have increased the dogs’ expectations that there was no food to be found in the new location, similar to the empty bowl location.

It appeared that the stress smell made the dogs behave with more caution. The “pessimistic” response could be a way for them to conserve energy and avoid potential disappointment.

Overall, the odor of a stressed human, even unfamiliar, can affect a dog’s emotional state and learning ability.

The team also figured out that the dogs kept improving their learning about the presence or absence of food in the two trained bowl locations. They seemed to learn faster when subjected to the stress smell.

“Understanding how human stress affects dogs’ well-being is an important consideration for dogs in kennels and when training companion dogs and dogs for working roles such as assistance dogs,” Dr. Rooney explained.

The study helps strengthen our bond with dogs and may lead to more effective training and care. It is published in Scientific Reports.

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Emily  Chan is a writer who covers lifestyle and news content. She graduated from Michigan State University with a ... More about Emily Chan

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