UK researchers have determined that dogs can accurately identify changes in human breath and perspiration caused by processes connected to psychological stress with a 93.75% accuracy rate.
Image Credit: asia.marangio via Shutterstock / HDR tune by Universal-Sci
The study
Our bodies emit chemical messages in the form of scents that have mainly evolved for communication between humans. However, as dogs have a long history of domestication, living side by side with humans, researchers asked themselves if dogs are capable of connecting these chemicals to conditions like panic, stress, and anxiety.
For their study, the team took sweat and breath samples from people both before and after a fast-paced math assignment. In addition, self-reported stress levels were taken into account alongside objective measurements based on blood pressure and heart rate.
From all the samples, the team picked 36 samples of people that reported high-stress levels (verified by the blood pressure and heart rate data). The samples were exhibited to 4 different dogs of varying breeds within a few hours of collecting. The dogs had been trained, employing a clicker and a kibble, to match scents in a discrimination task.
During the test, the trained dogs needed to find the stress sample and disregard the relaxed sample, taken from the same person, which was also part of the lineup.
One of the dogs dat particpated in the study, sniffing a sample. - Image Credit: Kerry Campbell, CC-BY 4.0
Impressive results
In general, dogs were able to recognize and act in an attentive manner on the sample collected under stress in 675 out of 720 trials, or 93.75% of the time, which is significantly more often than would be predicted by chance (p 0.001). The difference in precision between individual dogs ranged from 90% to 96.88%.
The authors come to the conclusion that dogs are capable of smelling scents linked to changes in the Volatile Organic Compounds (VOCs) that humans produce in response to stress.
The findings shed new light on the relationship between humans and dogs and may provide a meaningful addition to future training programs for service dogs specializing in PTSD and anxiety problems, as they are currently trained to respond predominantly to visual cues.
If you are interested in more details about the study, be sure to check out the paper (published in PLOS ONE) listed below.
Sources and further reading:
Dogs can discriminate between human baseline and psychological stress condition odours (PLoS ONE)
Research links owning a dog with living a longer life (Universal-Sci)
Is your dog happy? Ten common misconceptions about dog behaviour (Universal-Sci)
Dogs can distinguish between humans doing something on purpose and doing something by accident (Universal-Sci)
How old is my pet in dog years or cat years? A veterinarian explains (Universal-Sci)
Why cats are fussy eaters but dogs will consume almost anything (Universal-Sci)
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