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Can You Catch A Yawn?

Can You Catch A Yawn?

By Gavin Hammond

Whether or not we want to do it, we do. So do cats, fish and even eleven week-old foetuses. Involuntarily pandiculation is nothing to be ashamed of; it's just a posh way of saying yawning.

You’ll yawn at least once while reading this article. I don't mean to bore you, I'm simply exploiting the suggestive nature of your brain, just as if I was to mention chocolate you would develop a cocoa craving.

Why do we yawn?

Physiologically, it is often quoted that our bodies induce the yawn reflex to take on board more oxygen and expel large volumes of carbon dioxide from our lungs. This would explain why we yawn in groups, especially if there is a lack of oxygen in the corner of the pub where you and your mates are (yes, scientists do go to the pub and some even have friends).

Fact Box

  • You are less likely to yawn if you are schizophrenic.
  • Excessive yawning can be a sign of radiation poisoning.
  • 5% of patients using the anti-depressant drug clomipramine become aroused every time they yawn.
But then, surely, yawning to gain more oxygen would make us yawn during exercise which isn’t the case (no, not all scientists exercise). In fact, research has shown that pumping a room full of clean, breathable oxygen does not reduce the amount of yawning.

Perhaps the most believable theory behind yawning is that of boredom. I routinely yawn when reading articles published elsewhere than at the Null.

However, Olympic athletes yawn immediately before they compete in their event, as paratroopers before leaping out of a plane. How can they possibly be bored? In fact, a single yawn can increase your heart rate by as much as 30%, so yawning could be the body's subconscious way of preparing you for action.

It is even hypothesised that yawning is an ancient form of communication. Maybe yawning was how cavemen showed their alertness levels to one another, just like laughing shows others we are happy and crying shows that we are sad. Yawning could also have been a way of intimidating others since it causes us to bear our teeth.

Is yawning contagious?

We've all noticed that when one person yawns, it sets off a chain reaction of yawns amongst others in the group. Why does this happen? And is yawning really contagious?

"Yawning dogs are able to incite yawning in humans"
Responsibility could lie with the human brain's mirror neuron system (MNS – not to be confused with a popular internet chat program or a UK high street store).

The MNS hosts special brain cells which are activated when we do something, or when we sense someone else doing that very same thing. When we consciously imitate the action of someone, the mirror neurons become active.

However, research has shown that the cells in the MNS show no more activity during contagious yawning than during non-contagious events.

During the research, volunteers reported a large desire to yawn when seeing someone else yawn, coupled with a large deactivation of a second site in the brain, the left periamygdalar region.

This region has been previously linked with unconscious emotional expressions recorded in faces. What is fascinating is that yawning dogs are able to incite yawning in humans, meaning that the contagion of the yawning reflex is not restricted to one’s own species.

To summarise: we don’t really know why we yawn or why it’s contagious. Ladies and gentlemen, there’s research to be done. Send us your ideas and let’s get cracking.

Let Gavin enlighten you on the subject of spare body parts or visit his page to see what else he's been up to.

Or try some more infectious science:

- Bizarre - Honey trap for viruses
- Sad - Big blow for lovers
- Interesting - E. coli: friend or foe?
- Pleasing - Laughter is the best medicine

External link:

Go here for the biggest collection of pictures of yawning animals in the world.

Image: Hilary Quinn

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17 May 2010
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