Theories abound about why people yawn? Dogs do it, lions do it, babies in the womb do it -- but nobody knows why.

If you think yawning is simply bad manners, think again, for scientists say that it’s part of what makes us human.

Theories are abound about people yawn? Dogs do it, lions do it, babies in the womb do it -- but nobody knows why.

Now, a team, led by Professor Steve Jones at University College London, has claimed that far from being bad manners, yawning is a sign of our deep humanity, ‘The Daily Telegraph’ reported.

According to Prof Jones, yawning is catching and this may be a hint that the action evolved as a social cue -- “time for us all to go to bed” -- though as usual when evolution and human behaviour meet, the tie is speculative at best.

“However yawns arise, and whatever they signify, such a spontaneous copying response to a second person’s signal of mood is an unmistakable sign of empathy; of an ability to understand and to react to someone else’s state of mind.

“Empathy is what makes us into social and cooperative beings, and the speed and extent with which a person yawns in response to another’s involuntary gape may be a quick and objective measure of to what degree he or she might be blessed with those useful talents.

“Chimps do yawn, and they, like us, respond in kind when shown a computerised avatar indulging in the pastime. For them, though, the gesture is a statement of dominance rather than sympathy and in other primates it may even be a sign of an imminent attack.

“Perhaps what most people regard as an impolite act, to be disguised with a strategically placed hand when in company, is instead a deep insight into what it means to be human. Man as a yawning rather than thinking ape may lack dignity, but reveals a new and attractive side to his personality,” Prof Jones said.

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