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A dog’s nose knows when you’re stressed, according to a new study fromQueen’s University Belfast.
“While it is likely that in a real-life context, dogs are picking up on our stress from a variety of context cues, we have shown using a laboratory study that there is a confirmed odor component that is likely contributing to dogs' ability to sense when we are stressed,” animal psychologist Clara Wilson wrote, perNBC News.
In test sessions for the study, researchers presented dogs with samples from humans before they did a math problem and after. The samples were taken just four minutes apart from humans who had to count backward from 9,000, using in units of 17, and who had to do so in front of two researchers. Heart rate and blood pressure measurements were also taken, and participants also filled out questionnaires asking about their stress after the fact.
“If the participant gave a correct answer [to the math question], they were given no feedback and were expected to continue, and if they gave an incorrect answer, the researcher would interrupt with ‘no’ and tell them their last correct answer,” Wilson toldCNN.
The test started with 20 dogs, trained to point their noses at the samples, but 16 dogs were removed from the study for different reasons, including lack of attention and boredom. The four remaining dogs were presented with a machine containing an unused piece of gauze, a sample from a stressed person, and one from the same person when unstressed. Remarkably, 96.88 percent of the time, the dogs correctly identified the stressed sample.
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These findings could lead to scent-based training for PTSD service dogs, Wilsonshared on Twitter. Researchers could not determine whether the dogs in the study felt empathy toward stressed individuals.
“Because the dogs were trained with positive reinforcement to find their target, they were visibly excited when they found it in the line-up, rather than showing any kind of stress themselves,” Wilson said.
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Dogs have far more smell receptors than humans, Virginia Tech professor Mark Freemantold CNN, which makes canines “extremely effective at differentiating and identifying odors,” he said.
“While we can’t know with certainty why dogs developed such keen olfactory senses, it is very probably related with the need to identify prey, potential threats, reproductive status, and familial relationships in a pack setting, among others,” Freeman, who was not involved in the study, said.
source: people.com
