Buzz
Dogs possess an extraordinary sense of smell: A dog’s nose is 10,000 to 100,000 times more powerful than that of a human. New studies show that when dogs detect stress in people, they respond to it through their keen sense of smell.
A recent study published in the journal Scientific Reports discovered that dogs tend to show pessimistic behavior after sniffing the sweat of an anxious individual. For the research, a group of scientists in the UK asked 11 volunteers to speak publicly and solve math problems in front of an audience to induce anxiety. In another session, the same participants watched relaxing 20-minute videos featuring calm scenery.
The researchers tracked the participants' heart rates and collected samples of their breath, saliva, and sweat to measure cortisol levels—a stress hormone found in bodily fluids. All participants also completed anxiety questionnaires before and after the study.
In another experiment, 18 dogs were trained to associate food with a specific bowl in a particular location. They also learned that a different bowl in another part of the room never contained food. The researchers then placed new bowls between the two locations to observe how the dogs reacted. The goal was to determine whether the dogs seemed hopeful or doubtful about the chance of food in an ambiguous bowl.
After repeatedly smelling the anxious volunteers’ sweaty clothing, the dogs were more likely to cautiously approach a new bowl placed closer to the empty one. This behavior suggested that the dogs expected there to be no food in the bowl and approached it with a pessimistic outlook. However, their behavior didn’t change when they smelled the sweat of relaxed individuals.
The scent of stressed sweat may affect a dog’s appetite more than their decision-making process. Stress tends to reduce hunger, so the smell of anxious sweat might make the dogs feel uneasy, causing their appetite to diminish. This research indicates that a stressed-out owner can negatively affect their dog’s mood and behavior.
The sensitivity of dogs to their owners' stress levels has been previously confirmed. A 2019 study examining this behavior asked participants about their personalities, such as neuroticism and openness. They also completed personality questionnaires for their dogs, focusing on traits like excitability, fear, and aggression.
The researchers then measured hair cortisol levels in 58 dogs and their owners. The study found that the cortisol levels of the dogs were closely aligned with those of their owners, suggesting that dogs are highly empathetic and experience similar emotional reactions to humans.
