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Now there’s scientific evidence that sheds more light on one of Barkley’s impressive skills in a long list of endearing traits: the ability to smell when you’re stressed.
Dogs can smell the difference between a human’s smell when they’re stressed and when they’re calm, according to a study published Wednesday in the journal Nature. PLOS ONE magazine.
Earlier research showed that canines can smell when a person is happy or scaredbut this latest study removed other competing scents and measured participants’ stress levels to increase the accuracy of the results.
First, the researchers collected breath and sweat samples from study participants to use as a baseline. The subjects then performed a mental calculation, counting down from 9,000 to 17 in front of two researchers for three minutes.
“If the participant gives the correct answer, they are given no feedback and are expected to continue, and if they give the wrong answer, the researcher interrupts with “no” and gives they know their final correct answer,” said Clara Wilson, lead author of the study. , a PhD candidate at Queen’s University Belfast in Northern Ireland.
The team collected another batch of breath and sweat samples after completing the task.
In addition, the researchers collected reports of stress levels, heart rate, and blood pressure before and after performing the assigned task. Thirty-six participants who reported feeling stressed, increased heart rate, and blood pressure showed their samples to the dogs.
The researchers presented breath and sweat samples after completing the task from one person to 20 people dogs along with two other blank controls. The canines are needed to select the correct sample at least seven out of 10 times to move on to the next stage.
In the second and final stages, the research team gave four dogs that had passed stage one the same sample they sniffed in stage one along with a sample from the same individual collected before the task. service and a blank form. Presented with these options 20 times, the dogs needed to successfully identify the initial “stressful” scent after the task at least 80% of the time to produce results.
The dogs picked the right samples in 93.8% of the test, which suggests that the stress smell was quite different from the original samples, Wilson said.
“It is fascinating to see how dogs are able to distinguish between these odors when the only difference is the psychological stress response that has occurred,” she said.
Dogs have 220 million won olfactory receptors compared to humans’ 50 millionsMark Freeman, assistant clinical professor in the department of small animal clinical sciences at Virginia Tech in Blacksburg. He was not involved in the study.
Olfactory receptors are tiny nerve endings located inside the nostrils that allow you to smell, he says.
“While we can’t know for sure why dogs have developed such keen olfactory senses, it is most likely related to the need to identify prey, threats, and threats,” says Freeman. latent, reproductive status and familial relationships in a pack with other animals.
Twenty pet dogs were recruited from across Belfast, Northern Ireland, and four completed the entire study.
Most dogs don’t finish because they show signs of anxiety when separated from their owners, or they can’t concentrate all the time.
If the canines in the study were raised from birth for the purpose of stress sniffing, it’s likely more dogs would complete the study, he said.
There is a cocker spaniel, a female parakeet, a male terrier, also known as a terrier, and a type of female terrier. Their age ranges from 11 to 36 months.
All dogs have a strong sense of smell, but spaniels, terriers, and hounds are likely to use olfactory receptors more often than hounds, Freeman says. This may have been a factor in their success in the study, or it may have been coincidental because other breeds such as retrievers also have excellent smelling skills.
Service dogs that support people with mental health conditions such as anxiety and post-traumatic stress disorder may benefit from the findings, Wilson said.
“Knowing that there is a detectable odor component to stress could increase discussion about the value of scent-based training using samples from individuals over time,” she said. stress points versus calm.
More tests outside the lab are needed to see how the results of this study apply in the real world, Wilson said.
The findings also open the door for future studies to investigate whether dogs can distinguish between emotions, plus time can detect odors, she said.