Owners report that their dog notices a bad day, and earlier work suggests dogs pick up on human stress. Posture, voice and face all leak the same information, so a dog watching a person has plenty to go on. Smell alone, with the person absent, is a harder test.
It can, from breath and sweat alone. Four dogs picked the over the same person’s calm sample and a blank on 93.75 percent of 720 trials, well above the one in three expected by chance. An acute stress response therefore changes the a body gives off.
Previous research suggests that dogs can detect when humans are experiencing stress. Whether the odour alone carries that information is a separate question, since a dog in the room can also read a face, a voice and a posture.
The design strips all of that away. Combined breath and sweat samples came from participants at baseline and again after a stress-inducing mental arithmetic task, with each person’s stress confirmed by self-report and by physiological measures recorded through a Biopac MP150 system.
Thirty-six participants’ samples went to four dogs across thirty-six sessions. Each session ran ten , in which the dog learned to alert on a stress sample set beside two blanks. Twenty discrimination trials followed, in which the stress sample appeared alongside the same person’s and a blank.
Performance ranged from 90.00 percent to 96.88 percent accuracy, with a combined accuracy of 93.75 percent across 720 trials. A binomial test against a one in three chance of success put the proportion of correct trials far above chance, which points to applications for emotional support and post-traumatic stress disorder service dogs.
wat. Breath and sweat alone told the dog which sample came from a stressed person.
wat wat
It separates what a dog smells from what a dog sees, which matters for training assistance dogs to respond to a person rather than a scene.
How do we know?
Wilson and colleagues took breath and sweat from thirty-six people before and after a mental arithmetic task, confirmed the stress with self-report and physiological recordings, and ran a double-blind three-alternative forced-choice test.
What is still unknown
Four dogs, one kind of laboratory stressor, and a pair of samples taken minutes apart.
Learn something?
Where to next
Why do some people insist asparagus does nothing to their urine?smell
Can you smell that somebody has come down with something?smell
Can you tell where a smell is coming from with your nose alone?smell