Dogs Can Detect our Stress and it Profoundly Impacts Them

Dogs can detect human stress, and a new study shows that this scent may cause dogs to make ‘pessimistic‘ decisions, reflecting a similar emotional effect. This is the first scientific evidence that human stress odors influence dogs’ emotions and learning, according to UK researchers, and it may provide valuable insights into the ancient bond between our species.

While it may not surprise dog owners that their pets can sense human moods, the study indicates that this ability is stronger than many realize.

“Owners know how attuned their pets are to their emotions, but we demonstrate that even the odor of a stressed, unfamiliar human impacts a dog’s emotional state, perception of rewards, and ability to learn,” says Nicola Rooney, a senior author and human-animal interactions researcher at the University of Bristol.

Chemosignals in Human Sweat Can Subconsciously Influence Emotions and Decisions

Previous human studies have shown that we can subconsciously detect chemosignals in others’ sweat, which can subtly influence our own emotions and decisions.

Recent findings reveal that dogs also pick up these signals from us, but Rooney and her team wanted to understand how our stress odors affect them.

Given dogs’ proficiency at reading human verbal and non-verbal cues, the researchers chose not to expose them directly to stressed humans.

Instead, the researchers gave dogs sweat and breath samples from three unfamiliar volunteers, collected while the volunteers were either relaxing or undergoing stress.

The relaxing activity involved watching a nature video, while the stress test involved frustrating math instructions and public speaking.

Eighteen Dog-Human Pairs Tested with Odor Samples to Assess Food Bowl Preferences

The researchers recruited 18 dog-human pairs to participate in trials with the human odor samples. During training, dogs learned that a food bowl at one location always contained a treat, while a bowl at a second site was always empty.

The dogs quickly approached a bowl in the positive location (P) associated with treats, while they were slower to approach a bowl in the negative location (N) with no treats.

This eager behavior indicates “optimism,” reflecting an animal’s emotional state, based on previous research linking positive and negative emotions to “optimistic” or “pessimistic” decisions.

After training, the researchers placed bowls in new locations between the original two to see how quickly dogs approached.

The researchers introduced three new locations, labeled near-positive (NP), middle (M), and near-negative (NN), based on their proximity to the original sites.

They repeated these experiments while exposing dogs to odor samples from stressed or relaxed humans, or to no odor at all.

Dogs Avoided Near-Negative Bowl Position When Exposed to Stress Scent

Dogs approached a bowl in the near-negative position less frequently when they smelled the scent of a stressed stranger, compared to when they smelled the scent of a relaxed stranger or a blank cloth.

The stress odor was less discouraging when the bowl was in the middle or near-positive position, but when the bowl was near the foodless zone, the odor was enough to dampen their hopes.

When dogs weren’t exposed to the stress odor, the near-negative bowl location didn’t dissuade them as much. This suggests that dogs consider ambient odors along with the bowl’s position to estimate the likelihood of finding food.

“Working dog handlers often describe stress traveling down the lead, but we’ve shown it can also travel through the air,” Rooney says.

The subdued response from dogs exposed to human stress odor qualifies as pessimism, hinting at a negative emotional state. This may be adaptive, helping dogs conserve resources or avoid frustration.

Much of this dynamic is still poorly understood, and more research is needed to clarify how our odors affect the way dogs feel and learn.

Given the importance of dogs to humans globally – as co-workers, partners, and friends – it’s wise to follow clues that might bolster our bond.

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

Read the original article on: Science Alert

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