*YAWN*

You know how yawns are contagious? You see someone yawn, and you can't help but want to gape one too. Well, the other day, the CEO yawned in his office next door. I yawned in response, but only because I heard him yawn.

So if you record a yawn sound, would hearing it make you want to too? Or is it a more sub/super-sonic signal sent that humans pick up, but recordings can't? (This was at the same distance as the one he let rip, so evidently the yawn reach at least as far as odourous travel range.) Do pets get affected too? I wonder.