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22nd Apr 2024

Why do we yawn even when we’re not tired?

Anna Martin


I’m yawning just writing this

Okay in fairness I am tired, but I think most of us can agree there are times when we yawn and we’re like “eh but I got eight hours last night?”

It’s probably rare, but it’s a possibility.

So why is it that even when we’re not particularly sleep-deprived we’re sitting there with our mouths agape? Well, of course, there’s some science to it.

Why do we yawn?

According to Psychology Today, it has little to do with the amount of oxygen your body takes in, despite what a lot of us have been led to believe over the years.

In experiments, subjects yawn just as much in oxygen-rich air as they do in an oxygen-poor atmosphere.

Apparently yawning is more a response to boredom than anything else.

When researchers showed students ages 17-19 music videos and colour bar test patterns, those who saw the test patterns yawned nearly twice as often as those who watched videos, and their yawns lasted longer.

Yet this is only one of a list of reasons why we seem to go slack-jawed at random parts of the day.

Stress and anxiety

Credit: Canva

This might sound like the exact opposite of what you would expect, considering when we are stressed or anxious everything seems to be heightened but science tells a different story.

Studies have shown that fish, reptiles, birds and mammals all tend to yawn more before and after stressful situations, but experts don’t quite understand why this happens.  

There are theories as to why it happens though, like for example, it’s a way for our bodies to counteract the shallow breathing that typically occurs when we’re under pressure.

Others think it’s an example of displacement behaviour or behaviours we do out of context during moments of frustration or conflict, such as scratching our heads or putting our hands on our hips.

The temperature of your brain

Some of the research into why yawning happens has pointed at its ability to cool the brain, with one study suggesting that people yawn more during winter than in summer, when the air outside is cool enough to make a difference.  


Psychologist Steven Platek and his team at Drexel University in Philadelphia gave 65 college students personality tests.

The tests measured their empathy, or how well they perceived and responded to the mental states of other people.

Platek then observed through a one-way mirror how the students responded as they watched videos of people yawning.

The students who scored high for empathy yawned more often in response to the videos than their less compassionate peers.