Have you ever wondered why you yawn when you’re nervous or stressed? Did you know that athletes do it before competitions, musicians do it before going on stage, even paratroopers do it before jumping out of a plane for the first time, but is there a reason why?

Of all the involuntary physical reflexes humans experience before stressful events, yawning seems not only improbably, but a little bit ridiculous! Most people would think you yawn because your tired, but according to Robert Provine, a University of Maryland neuroscientist, yawning can occur due to arousal or de-arousal.

“Nervous people will definitely yawn more,” says Provine, “but there haven’t been a lot of formal studies investigating why.” That might be why the TSA includes “exaggerated yawning” in its 920point checklist of suspicious passenger behaviors.

Read the full story here :: Big Question: Why Do I Yawn When I’m Nervous or Stressed?