Reading: True/False - 2023 tavaszi

Scientists ran an experiment which showed that dogs can tell the difference between the smell of a person when they're relaxed and when they're stressed. Researchers at Queen's University Belfast worked with four dogs and 36 humans. The dogs included in the study were pets, volunteered by their owners. First, researchers taught the dogs to use a special smell-testing device. Then, they collected sweat and breath samples from the human participants under two different conditions: in a non-stressful and a stressful situation. When people were calm, their blood pressure and heart rates were measured and then they were asked to wipe their skin with a clean piece of cloth. Then they had to put the cloth sample in a tube and breathe on it hard three times. The study team then collected another round of breath and sweat samples a few minutes later, after the people had completed a difficult maths task, counting backward in their heads from 9,000 in units of 17 in front of two researchers for three minutes. The researchers kept telling the people to hurry up. After the task the participants reported feeling stressed, and their blood pressure and heart rate had gone up. Then the dogs were given a relaxed and a stressed sample from each person. The dogs correctly identified the stressed sample in 94% of 720 tests. The study provides evidence that dogs can smell stress from breath and sweat. Researchers say the skill could be useful when training therapy dogs.