If you have ever wondered why we yawn and also had your suspicions that it might be infectious or contagious the latest research on the topic will interest you.
In a study of autistic children, researchers at Birkbeck College, London say showing empathy has a lot to do with yawning.
The researchers tested the reaction of autistic children and normal children when watching video clips of people yawning and then simply moving their mouths.
They say what they discovered supports evidence that people who identify better with others are more prone to contagious yawning.
Atsushi Senju, a researcher at the university says scientists have always known that one yawn often leads others to follow suit but what triggers the phenomenon is unclear.
A yawn, when the mouth is opened wide is a reflex of deep inhalation and exhalation associated with being tired, with a need to sleep, or a lack of stimulation.
A yawn gives a powerful non-verbal message with several possible meanings, depending on the circumstances and some people believe a mechanism in the brain that makes people feel empathy also causes them to yawn when they see others doing the same.
Another speculated reason for yawning is nervousness which encourages the notion that yawning is a form of communication.
On average a yawn lasts about six seconds and 55 percent of people will yawn within five minutes of seeing someone else yawn; reading about yawning will make you yawn and Olympic athletes often yawn before competition.
For the study the researchers showed videos of people yawning or making other mouth movements to 24 children with autism spectrum disorder and to 25 normally developing children.