In the world of dogs and cats, it wouldn't be a stretch to say that canines seem more optimistic and felines less so. But a dog's optimism can apparently be dampened by their human's emotional state, according to new research.
If you've ever gotten bummed out from hanging with a negative friend all weekend, then you've experienced what's known as "emotional contagion." This term refers to the way in which the olfactory, visual, and auditory cues coming off the people around us can affect our own emotional states.
Science has already uncovered the fact that dogs are also prone to a degree of emotional contagion from humans. For example, one study showed that their heart rate climbs and they exhibit an increase in stress-related behaviors when smelling odors from humans who are in a fearful state.
While we've known that dogs can pick up on our cues, what we haven't been able to see is how their awareness of our emotional signals might affect their cognition. A new study out of the UK's University of Bristol attempted to find out exactly that.
A research team there decided to gauge a dog's degree of optimism or pessimism after they had sniffed odors of sweat and breath samples taken from humans who were either in a stressed state (induced by needing to complete an arithmetic test) or in a relaxed frame of mind (induced by listening to soundscapes).
Because dogs can't self-report on their degree of optimism or pessimism, the researchers came up with a proxy. They placed two bowls in one room. In one location, the bowl always had a treat while in the other, it was empty. After the dogs had learned to favor the treat-containing bowl, the scientists then exposed them to the different stressed or calm odors and put them back in the same room.
This time though, a third bowl was added between the two they were already familiar with.
If the dogs approached the third bowl quickly, it was seen as a sign of optimism as in: "Wow, there's another bowl here; it's gotta have a treat!" If, however, the dog approached the bowl more slowly, it was seen as a sign of pessimism as in: "Aw, nothing ever good happens to me, so I don't need to waste any energy running over to a bowl that's probably empty."
When the dogs first sniffed the relaxed odors before entering the room, they approached the third bowl more quickly, and therefore more optimistically. When they sniffed the stressed odors before investigating the room, they made a much slower approach to the third bowl, which the researchers took as a pessimistic mindset.
“Dog owners know how attuned their pets are to their emotions, but here we show that even the odor of a stressed, unfamiliar human affects a dog’s emotional state, perception of rewards, and ability to learn," said lead study author Nicola Rooney, Senior Lecturer in Wildlife and Conservation at Bristol Veterinary School. "Working dog handlers often describe stress traveling down the lead, but we’ve also shown it can also travel through the air."
A total of 18 canines were involved in the study, representing a range of purebred and mixed breed dogs. Rooney says the research could help in our training and caretaking of the animals.
"Understanding how human stress affects dogs' wellbeing is an important consideration for dogs in kennels and when training companion dogs and dogs for working roles such as assistance dogs," she said.
The research has been published in the journal, Scientific Reports.
Source: University of Bristol
