A team of researchers from the University of Bristol, Cardiff University and British charity Medical Detection Dogshave studied the impact of the smell of stressed humans on dogs. According to the study, published in the Scientific Reports journal, pets can indeed detect the smell of stress and this affects their decision making.
The fact that dogs can detect the human smell of stress isn’t new. Cortisol, one of the hormones released during a stress reaction, can be picked up by dogs and this ability is amongst others used by service dogs in order to guide their masters. However, no research had been carried out as far as the dog’s emotional reaction to human stress goes.
“Some people have looked at, can dogs actually detect differences in odour. And they have. But nobody had really looked at how that affects the dog’s emotions”, said Dr Zoe Parr-Cortes from the Bristol Veterinary School, lead author of the study. “Being a species that we’ve lived and co-evolved with for thousands of years, it kind of makes sense that dogs would learn to read our emotions because it might be helpful to them to know if there’s something threatening in the environment or some stressor that they need to be aware of.”
In order to study the impact of human stress on dogs, a test very similar to the human ‘glass half full / glass half empty’ experiment was run. The researchers first trained 18 dogs to know that a bowl on one side of a room was always full, while one on the other side was always empty. Once they successfully understood this principle, the bowl was placed at three ambiguous locations (“near-positive”, “middle” and “near-negative”) instead to see with how much confidence the pooches would approach it.
“When exposed to stress odour during session three, dogs were significantly less likely to approach a bowl placed at one of the three ambiguous locations (near-negative) compared to no odour, indicating possible risk-reduction behaviours in response to the smell of human stress”, Parr-Cortes explained.
Even though more research is needed to fully grasp the meaning of the results, according to Parr-Cortes, it already shows the importance of positive reinforcement while training your dog. “Importantly, it highlights how in-tune dogs are at picking up on mood. So keeping your relationship with your dog (…) based on positive reinforcement and happy, fun engagement is the best way to have a good relationship and a happy dog”, she said.
