One of the most common yet enigmatic human actions is yawning. When we're bored, exhausted, or even just notice someone else yawning, we do it. Excessive yawning is usually innocuous, but ...

Bournemouth University neuropsychologist Simon Thompson is an expert on yawning. In 2011, he posited that high levels of the stress hormone cortisol may be a direct cause of yawning. “We believe that ...

But why? Surely we cannot all be that tired. The truth is the science behind yawning is much more complex than just a few hours too little sleep. Even more complex? Why we seem to yawn because ...