New research: The smell of human stress can affect dogs' emotions
The new research at the University of Bristol is the first to examine how the smell of human stress affects the learning and emotional state of dogs.
Evidence in humans suggests that the smell of a stressed person subconsciously affects the emotions and choices of those around them.
Researchers at the Bristol Veterinary College used a test of 'optimism' or 'pessimism' in animals, based on findings that optimistic or pessimistic choices in humans indicate positive or negative emotions. "Phys.org".
18 owners and dogs were recruited to participate in a series of trials with different human odors. During these tests, the dogs were trained that the container contained snacks when placed in one location, but that it was empty if placed elsewhere. The dogs approached the location with the snacks faster. Then it was tested how quickly they approached the new, uncertain location of the vessel, between the two original ones.
Fast access reflected optimism regarding the presence of food in a new location – a sign of a positive emotional state, while slow access indicated pessimism and negative emotions. The tests were either unscented or scented with sweat and breath samples of people in a stressed or relaxed state.
The researchers found that because of the scent of stress, dogs approached a new bowl location more slowly than the nearest empty bowl location. This effect was not observed in the case of the scent of a relaxed person.
These findings indicate that the stress odor may reinforce the dogs' expectation that there is no food in the new location, as in the case of a nearby location with an empty bowl.
A pessimistic reaction reflects a negative emotional state and may be a way for the dog to conserve energy and avoid disappointment. It was also found that the dogs continued to improve their knowledge of the presence or absence of food in the two familiar locations and that they made faster progress when the stress odor was present.
Understanding how human stress affects dog behavior is an important factor in dog training. Dog owners know that their pets are in tune with their emotions, but now it's being shown that even the smell of a stressed-out stranger affects a dog's emotional state, perception of reward and ability to learn. Stress not only goes through the leash, but also through the air.
