A recent study conducted in the United Kingdom shows that four-legged friends can smell stress in humans, something that appears to affect their emotions and reactions.
The study, published in the journal "Scientific Reports", is the result of a collaboration between "University of Bristol", "Cardiff University" and a charitable association oriented towards animals, mainly dogs.
The researchers collected sweat and breath samples from 36 volunteer participants before and after doing a difficult math exercise. They reported their stress levels before and after the task, and the researchers only used samples where the participants' blood pressure and heart rate had increased. Four puppies were also included in this study.
"No one had really looked at how the smell of human stress affects the emotions of puppies," says veterinarian Zoe Parr-Cortes. It's been proven that dogs can be trained to detect changes in levels of cortisol, a hormone that floods the body in times of stress, but researchers wonder how smelling stress-related changes might affect dogs' emotional state.
"Being a type of animal that has coexisted with humans for many years, it makes sense that dogs can read their owners' emotions to understand if they are in a truly threatening or stressful environment," continues the doctor.
The dogs were trained to search for a range of scents and alert researchers to the correct sample, and this is the first study to show evidence that dogs can smell stress from people's breath and sweat.
The fact that the study relies on volunteers who are unfamiliar with the dogs shows that the dogs' response is universal and not learned.
So this study points out that dogs don't need visual or auditory cues to perceive human stress.
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Source: NPR
