Why do we yawn? Nothing to do with boredom - we're just cooling our brains, say scientists
A new study has suggested that the reason we yawn has nothing to do with tiredness or boredom, but actually works in order to cool down our brains and help us think a little clearer.
Like any computer the brain has an optimal working temperature and when it becomes too hot yawning helps cool it down, increasing both the heart rate and blood flow while delivering a big gulp of air to the head, cooling the blood in that area.
Previously it’s been thought that yawning served a respiratory function, helping to wake us up with a jolt of oxygen when we were feeling sluggish, but studies have shown that yawning doesn’t actually increase oxygen levels in the body; something that tallies with the simple observation that we don’t yawn when we exercise, a time when we definitely need more oxygen.
So why do we yawn when we’re tired? Well, both sleep deprivation and exhaustion are known to increase brain temperature, so while it’s true that we yawn to combat lack of sleep, yawns don't make us ‘more awake’ but instead help keep our brains operating at the right temperature.
Yawning isn't limited to humans - most animals with a spine yawn.
Researchers from the University of Vienna observed pedestrians’ yawning habits in both Austria and the US and found that contagious yawning was most frequent in a ‘thermal window’ when it was cold enough outside for the yawned air to cool the body down, but not so cold (or so hot) that the air would have harmful consequences. This meant that citizens in sweltering Arizona yawned more in winter while in chilly Vienna they yawned more in summer.
The research, published this May, tallies with a number of previous studies such as one from the University of Albany that found that contagious yawning could be directly influenced using hot and cold packs. Researchers found that subjects watching a video of people yawning were 41 per cent likely to yawn themselves when holding warm pack to their head, but only nine per cent likely to yawn when holding a cold pack.
This theory of yawning-as-thermoregulation also tallies with explanations of the behaviour as ‘positively contagious’; aka a herd behaviour that helps keep every member of the group alert, as well as having the beneficial side effect of stretching out bodies to keep them limber (word fact: yawning accompanied by stretching is known as ‘pandiculation’).
Our susceptibility to contagious yawning is also affected by our capacity for empathy. Studies have shown that contagious yawning first begins in children at the same age as they learn to identify others’ emotions (about 4 to 5 years old) and that children with autism (a neural condition that impairs social interaction) are less likely to yawn when shown videos of others yawning.
Yawning is so contagious that we only need to read about it to want to yawn ourselves. In fact, you’ve probably yawned at least once since reading this article. At least we know that that’s not because you’re bored – in fact, thanks to the yawning and your newly-cooled brain, you’re probably more alert than you were before.
- 1 End of the licence fee: BBC to back radical overhaul of how Corporation is funded
- 2 Raif Badawi, the Saudi Arabian blogger sentenced to 1,000 lashes, may now face death penalty
- 3 PornHub turns masturbation into energy in bid to save the planet
- 4 Dakota Johnson's 'It's only Isis' Saturday Night Live sketch sparks controversy
- 5 The remarkable archaeological underwater discovery that could open up a new chapter in the study of European and British prehistory
End of the licence fee: BBC to back radical overhaul of how Corporation is funded
Raif Badawi, the Saudi Arabian blogger sentenced to 1,000 lashes, may now face death penalty
PornHub turns masturbation into energy in bid to save the planet
Dakota Johnson's 'It's only Isis' Saturday Night Live sketch sparks controversy
White and gold or blue and black – what colour is the dress? An eyewitness gives a definitive answer
New theory could prove how life began and disprove God
This is what it's like to be dead, according to a guy who died for a bit
'Jihadi John': CAGE representative storms off Sky News accusing Kay Burley of Islamophobia
Ukip would cut billions from Scottish budget to fund English tax cuts
End of the licence fee: BBC to back radical overhaul of how it is funded
Russia's roadmap for annexing eastern Ukraine 'leaked from Vladimir Putin's office'
£40000 - £50000 per annum + benefits: Ashdown Group: Senior Systems Administra...
£35000 - £45000 per annum: Recruitment Genius: A fantastic opportunity for a t...
£14616 per annum: Recruitment Genius: This leading specialist in Electronic Ci...
Negotiable: Recruitment Genius: With year on year growth and a reputation for ...