Why Is Yawning So Contagious?

Yawning: A reflex act of opening one’s mouth wide and inhaling deeply.  

Why do we yawn? Snakes do it, fish do it, even babies in the womb do it – but the truth is nobody really knows why.  However the emergence of the new discipline of neuroscience – the scientific study of the nervous system – is investigating why we humans yawn – and the answers might surprise you.

Time to yawn

It happens on hot days more than on cold, which leads to speculation that yawning cools the brain. On the other hand, someone running a fever yawns less than normal, while uncontrollable yawning maybe a symptom of diabetes or a stroke. Yawning often peaks just before bed-time but then, oddly enough, stops when we are lying down – still awake – in bed. Yawning is also common just after we get up – when, presumably, we are not tired at all.  

Theories abound

Different species do it for different reasons – birds may use it as a cooling mechanism while snakes appear to use it to readjust their detachable jaws after swallowing a large meal. In humans yawning is believed to have evolved as a social cue to signal to others – an expectation that something different or novel is about to happen – a kind of non-verbal way of saying ‘time for us all to go to bed’. This might explain the increase in yawning observed in parachutists about to jump and in negotiators – the moment talks take an unexpected turn.

Yawning is catching

But there is another unexpected twist to yawning. Like laughing and vomiting – yawning in humans is a contagious behaviour. Once we see someone else do it we are inclined to copy it.  Yawning is in fact by far the most contagious behaviour for us humans and such a spontaneous copying response to a second person’s signal of mood is an unmistakable sign of empathy; the ability to understand and to react to someone else’s state of mind. This might explain why people with autism or with schizophrenia find it hard to yawn – and they respond less to the yawns of others than do most of us.

Show you care – yawn back

Empathy is what makes us kind and people-friendly and the speed and extent with which a person yawns in response to your yawn may be a fast way of finding out if he or she is on your emotional wavelength – a kind of non-verbal way of saying ‘I feel you brother’.  In this way, yawns are most contagious within families but are less inclined to be copied by strangers. The captain of a football team might yawn in the dressing room before an important game and then watch to see who is ‘with him’.  

Mirror mirror on the wa…. yawn

The recent discovery of the so-called mirror neuron system in the brain which helps us to respond sympathetically and empathetically to others may help explain why yawning is associated with empathy, Mirror neurons help connect us emotionally to other people. They help us to respond sympathetically towards others and allow us to anticipate others intentions. When you watch a good movie with good actors then that’s why you feel the way you do. In this way, yawning may be a powerful non-verbal activator of the mirror neuron system in others – explaining why it is so contagious.

He who dares – yawns

Far from being bad manners, yawning is a sign of our deep humanity. So, go on give a giant yawn for mankind.