Ever wondered why most people yawn after someone else has yawned?
The Naked Scientist Chris Smith says while there is no definite answer, there are plenty of theories on why yawning is contagious.
It's a visual thing, when we see people yawn it makes us want to yawn.— Chris Smith, Naked Scientist
One suggestion is that if you are in a group of people, if one person is feeling fatigued, it is likely that the others are too. So if one person yawns and makes themselves more alert then other people catch that yawn and other people yawn sympathetically, they also will become more alert....— Chris Smith, Naked Scientist
Smith says animals can also pass it on.
It doesn't appear to be just humans, you can catch yawns off your pets and your pets can catch yawns off you.— Chris Smith, Naked Scientist
Click on the link below to listen to hear more from Smith....