A yawn in response is a normal reaction of the body, but the absence of such a reaction is a cause for concern.
We'll tell you why you should be wary of people who don't yawn back.
According to a 2015 study by American scientists, there is a link between the lack of responsive yawning and psychopathy.
As part of the study, subjects, students at Baylor University in Texas, were shown videos of people yawning.
The study participants were also tested for their tendency to be cold-blooded and self-centered.
Subjects who yawned less often than others or who did not experience any emotions while watching the video received high scores in the test.
Earlier we talked about how to avoid emotional burnout.