According to the researchers behind a recent study, dogs can tell when we are upset.
It is well known that dogs have the ability to detect diseases including cancer, malaria, and Parkinson’s disease. “Man’s best friend” can also spot the signals that someone is about to have a migraine, an epileptic seizure, a narcoleptic episode, low blood sugar, or other medical emergencies.
Researchers recently discovered that canines can recognise variations in human breath and perspiration linked to stress in a study that was published in PLOS ONE. Additionally, the dogs are almost 90% accurate in their ability to spot these alterations.
“Body smells constitute chemical cues that have developed for communication, primarily within species,” the authors wrote. The researchers questioned whether dogs could be sensing chemical signals to respond to their owners’ psychological states given their involvement in supporting human psychological illnesses such as anxiety, panic attacks, and post-traumatic stress disorder (PTSD).
Tested and Trained
In order to conduct their study, researchers from Queen’s University Belfast took samples of non-smokers’ breath and perspiration before and after they completed a demanding arithmetic exercise. Participants’ physiological measurements, such as heart rate and blood pressure, as well as their self-reported stress levels, were also noted.
Four of the 20 dogs who were selected as pet dogs from the Belfast community made it to the testing stage. These four dogs ranged in age from 11 months to 2.25 years and included a cocker spaniel, a cockapoo, and two unknown breeds (lurcher-type and terrier-type). They were trained to match odours in a discriminating task using a clicker and food.
In order to be certain that a dog’s performance during the testing phase dropped to chance at the testing phase, this was because the stress and baseline samples were indistinguishable to the dog, and not because the dog “didn’t know how to do the task,” the authors stated that performance at above 80% correct (chance level) was needed in the training stages before the testing stages started.
The samples of 36 individuals who reported feeling more stressed as a result of the task as well as experiencing an increase in heart rate and blood pressure throughout the task were given to trained canines within three hours after being collected during the testing phase. Dogs were instructed to locate the participant’s stress sample, which was collected at the conclusion of the session. The same person’s relaxed sample, which had been taken minutes before the activity began, was also included in the sample options for the dogs.
In 675 out of 720 trials, or 93.75% of the time, the researchers discovered that dogs could detect the sample obtained under stress and execute their alert behaviour on it.
The dogs accurately alerted to the stress sample 94.44% of the time the first time they were exposed to a participant’s relaxed and stressed samples, according to the study’s authors. The accuracy of the individual dogs ranged from 90% to 96.88%.
This study shows that dogs can distinguish between human breath and sweat samples obtained before and after a stressful task, according to the study’s authors. According to them, dogs are able to detect changes in the olfactory profile of our breath and sweat caused by a “acute, negative, psychological stress response.”
They noted that their findings add to the body of knowledge on the “human-dog relationship” and that they could be used to improve the training of service dogs for PTSD and anxiety who are now only taught to respond to visual cues.