[Animals]Dogs can smell when we're stressed out, a new study shows

[Dr@g0n]

It’s long been widely believed that dogs can detect extreme emotions by smell. Now scientists at Queen's University Belfast in the U.K. have proven that a dog's nose knows. Acute stress changes the compounds found in human sweat and breath, research has shown. For the new experiment, four dogs were presented with sweat and breath samples collected from human volunteers — before and after the people engaged in a difficult math exercise. The canine participants were able to detect with a greater than 90 percent accuracy which samples came from before and which came from after the 36 human volunteers had spent three minutes trying to count backward, aloud, from 9,000 in units of 17, according to the report published Wednesday in the scientific journal PLOS One. “This study provides further evidence of the extraordinary capabilities of ‘man’s best friend,’” said the study’s first author, animal psychologist Clara Wilson.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,” Wilson said in an email. For their study, Wilson and her colleagues first set out to train a variety of 20 pet dogs to point with their noses at samples from a person who was stressed. (By the end of the training period, 16 dogs had been withdrawn for a variety of reasons, including attention issues and boredom.) The researchers tested the trained dogs with a machine that offered three choices: an unused piece of gauze, a sample from a stressed person and one from the same person when unstressed.
link:https://www.nbcnews.com/health/health-news/dogs-can-smell-stressed-new-study-shows-rcna49472