When someone nearby yawns, we often feel as if we've lost bodily control. Our jaws open involuntarily, overcome by some unseen force and compelled to mimic the gaping mouth in our midst. Merely thinking about yawning can cause you to yawn — an unrelenting problem for anyone pondering and writing about the subject.
No one knows for sure what triggers this automatic (and often unconscious) response, but experts have proposed a few theories. Whether simultaneous yawning raises our collective awareness or strengthens our social connections, it certainly seems that the behavior is infectious.
To understand why we find yawning so contagious, it's important to consider what causes yawns in the first place. For such a common phenomenon — the healthy average is up to 20 times per day — yawning remains somewhat mysterious. So what does yawning do?
One hypothesis is that yawning is simply your brain's way of regulating ...
