Dog owners have long believed in their pets' uncanny ability to sense their moods. Now, scientists have proven that dogs really are affected by their owners' emotions. Researchers from the University of Bristol discovered that dogs' behaviour changes when they smell the stress in our sweat and breath, making them more 'pessimistic.'
Dr Nicola Rooney, the lead author of the study, explains, "Working dog handlers often describe stress travelling down the lead, but we’ve also shown it can travel through the air." Previous research suggested that dogs are particularly sensitive to the moods and actions of those around them. However, it was not clear if smell played a role in spreading these emotional states.
Dr Rooney adds, "Dog owners know how attuned their pets are to their emotions, but here we show that even the odour of a stressed, unfamiliar human affects a dog’s emotional state, perception of rewards, and ability to learn."
To test this theory, the researchers recruited 18 human and dog pairs for a series of trials. Initially, the dogs were trained to recognize the difference between a good and bad situation. When a food bowl was placed in one location, it contained a treat, but when an identical bowl was placed in a second location, it was empty. The dogs quickly learned to approach the location containing the treat.
In the next part of the trial, the dogs were exposed to the odours of sweat and breath samples taken from humans who were either relaxing to soundscapes or stressed by taking an arithmetic test. The researchers found that dogs exposed to stress smells were significantly less likely to investigate the bowls, regardless of location. Conversely, when given the smell of a relaxed human, the dogs approached the bowls more frequently.
Dr Zoe Parr-Cortes, the primary author, explains that dogs have co-evolved alongside humans for thousands of years, leading to a phenomenon called 'emotional contagion,' where they pick up the moods of their owners. "This can be beneficial as a threat perceived by another group member could indicate a threat to themselves; therefore, detecting and responding to fear or 'alarm' in others can be advantageous in avoiding a common threat," she explains.
The researchers suggest that dogs may have developed a 'pessimistic response' to human stress to conserve energy and avoid disappointment. This discovery could help professional dog handlers and owners understand how their own emotions affect their dog's training. This is particularly important for working dogs in high-stress roles such as police work or search and rescue operations.
Dr Parr-Cortes adds, "It [human stress] can make them less likely to try something risky if they think they will be disappointed. Relaxed odour did not have this effect, so keeping calm or doing a relaxing activity before training your dog could reduce this effect."
While previous studies have shown that dogs react to human emotions, there has been limited research on how these emotions affect optimism and pessimism in dogs. The researchers hope to explore the effects of emotions like happiness or deep relaxation on dog moods in future studies.