A yawn is an involuntary reflex that involves opening the mouth wide and taking in a deep breath, followed by a slow exhale. Several theories exist about why we yawn, but researchers have not proven ...

Does looking at an image of a person yawning make you yawn? About half of adults yawn after someone else yawns due to a universal phenomenon called “contagious yawning.” Contrary to popular belief, a ...

Many theories have been proposed to explain why animals yawn, such as replenish oxygen supplies, cool the brain and even stretch the lungs. Now, a new study claims yawning evolved as a social cue to ...