What’s in a yawn?

It’s a reflex action that on average lasts about 6 seconds, it occurs more often than not in our most grueling lectures and at any time throughout the day. Yet yawning seems to be one of those things we find most difficult to explain.

Some articles put it down to tiredness or boredom, which tends to have been accepted as the truth by the general public. However, this theory has no more evidence to support it than any other interpretation of yawning. This leaves us with the difficult question of what really does make us yawn?

In my quest to explain this to my fellow students - who seem to be particularly in love with yawning - I first had to acquaint myself with the mechanics of a good yawn. I finally settled on Discovery Health's definition, that yawning is an involuntary action that causes us to open our mouth and breathe in deeply; a bit like when we read our monthly bank statement).

It goes on to talk in detail about where our diaphragm goes and the flexing of abdominal muscles, which, as interesting as it sounds, is not helpful when thinking about why we yawn. It all sounds easy enough to understand when put so concisely, but when we start to think about the benefits of wasting the bodies precious energy to yawn it starts to become very difficult to prove anything.

Interestingly, yawning is not unique in any way to humans; research has shown that even fish can yawn!

Although how they managed to prove this using specific tests surpasses me, this does support one of the main theories for yawning, called the ‘evolution theory’. As the name implies, it suggests that yawning first started a long time ago with our ancestors to put off any predators by showing them their teeth. The people who support this theory believe that it was also a sign to our ancestors to change activities. However, there are of course some flaws in this theory, one of the main ones being: How often do you see fish in a fish tank breaking their much loved pattern of swimming and eating to try something new?

The most popular theory is the ‘boredom theory’, which suggests that yawning is a result of fatigue; lack of sleep or of course, boredom. This definitely links in with the student theory! This theory does tend to appear true at first, especially as many of you will have experienced the tricky task of holding in a yawn, while having a particularly tedious conversation with someone. Even so, the theory cannot explain why yawning is ‘contagious’ or why you see some students yawning just before an exam, when they should be most alert.

A theory many people probably have not heard of is one that I came across in New Scientist. Psychologists Andrew Gallup and Gordon Gallup looked at the possibility of yawning being linked with boosting blood flow and cooling the brain. This would help to explain why yawning seems to occur at times where we need to be attentive, such as just before exams or during a lecture. It also gives an explanation as to why you can ‘catch’ a yawn, as Gordon Gallup explains ‘we think contagious yawning is triggered by emphatic mechanisms which function to maintain group vigilance’.

Translated into a more appealing version of English, Gallup is saying that yawning can be useful to keep a group of people alert. This therefore helps when trying to explain where yawning started, it would have been useful to our ancestors to remain alert to any potential predators. However in more modern times, predators come in a more complex and varied fashion. I shall let you to consider your immediate predator and you could try yawning them away.

Basically, there are plenty of theories about why we yawn and I will have to leave it up to you to decide which you find most convincing. What can be taken from all the different attempts to discover the meaning behind yawning is that it is definitely a lot more complex than simply taking a particularly deep breath.

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