"The dog smells fear" .. a new study confirms the "historical advice"
A recent study has proven the "old myth" that dogs can smell fear.
The study confirmed that exposure to stress in all kinds of physiological shifts in the human body, from heart rates to chemicals released into the bloodstream, can be smelled by dogs, especially stress-related changes.
This is the first time that researchers have explored in laboratory experiments how dogs can recognize smells and how they can identify when a person is in a stressful situation.
Besides giving us a deeper understanding of the relationship between dogs and their owners, the research can be used to improve training for dogs involved in anxiety support, panic attacks and PTSD.
Animal behavior researcher Clara Wilson from Queen's University Belfast in the UK said: "The results show that as humans, we produce different odors through our sweat and breath when we're stressed, and dogs can tell this apart from our scent when we're relaxed."
The research highlights that dogs do not need visual or sound cues to pick up on human stress.
The study involved four dogs - Treo, Fingal, Soot and Winnie - and 36 people, with a total of 720 smell tests performed in total.
Human volunteers were asked to complete a challenging math problem and self-report their stress levels at the same time.
Once the blood pressure and heart rate of each human participant were increased, sweat and breath samples were taken, and these were then shown to the dogs to see if the canines could alert the researchers to stress samples among the baseline control samples: relaxed samples taken 4 minutes before the task began.
Sure enough, that's exactly what the dogs did, with a high level of accuracy. In 94% of the 720 trials, the dogs were able to correctly alert the researchers to the stress sample.
"It was very surprising to see her so confident," Wilson told The Guardian.
It appears that chemical changes caused by stress can be picked up by dogs, and smells are the information dogs receive.
Previous studies have shown that dogs can reverse our stress levels and detect emotions like happiness and fear through the scents we give off, and this new research ties these two findings together well with some detailed data collection.
The new study could provide some useful insights into how dogs see the world and interact with the people they meet along the way.
"This is the first study of its kind, and it provides evidence that dogs can only smell stress from breath and sweat, which can be useful when training service dogs and therapy dogs," Wilson says.
He emphasized that the study helps shed more light on the relationship between humans and dogs and adds to our understanding of how dogs interpret and interact with human psychological states.