Dogs can actually smell when a human is stress, according to a recent study. They can tell the difference between when a human is calm and when they are stress. Amazing right?
As a starting point, Clara Wilson and her team of researchers obtained breath and sweat samples from study participants.
Then, they spent three minutes in front of two researchers doing a mental arithmetic test. The respondents had to count backward from 9,000 using increments of 17.
If the respondent got it right, they were left in silence. However, the researchers would interrupt them, if they got it wrong. After finishing the task, the research team took another set of breath and perspiration samples.
The researchers took the participants’ levels of stress, heart rates, and blood pressure before and after the experiment.
Thirty-six people who said they were anxious, with elevated heart rates and blood pressure, had their samples exhibited to dogs.
One person’s breath and perspiration after the test were shown to 20 dogs. Two blank samples are used as a control. In order to advance, the dogs needed to make the right choice seven times out of ten.
The last step of the research included showing the four dogs who had completed the first phase the same samples they had smelled in the first phase, coupled with a sample from the same person gathered before the test and a blank.
To draw any conclusions, the dogs had to correctly identify the original post-task “stress” aroma at least 80% of the time when presented with these alternatives 20 times.
The researchers noted that in 93.8% of trials, the dogs correctly identified the test sample. This indicates that the stress scents were distinctive from the control samples.
Helping in real-world situations
Wilson speculated that the results might be useful for service dogs that help individuals with mental health disorders including anxiety and post-traumatic stress disorder.
She said that “Knowing that there is a detectable odor component to stress may raise discussion into the value of scent-based training using samples from individuals in times of stress versus calm”.
These results give way for more studies to determine whether dogs are able to distinguish between different moods, and how long the scents remain noticeable.