Why do we yawn? The science behind contagious yawning.
Yawning is the opening of your airway and mouth to take a long, deep breath of air. It is a complex muscular movement.
Yawning is also known as oscitation. Yawning is mostly involuntary which means that we don’t have control over it. Most scientists consider it a reflex. However, you can make yourself yawn by breathing in gradually while retracting the tip of your tongue and opening your jaw repetitively.
Yawning most often occurs in adults immediately before and after sleep, during tedious activities and as a result of contagious quality. It is commonly associated with tiredness, stress, sleepiness, boredom or even hunger.
WHY DO WE YAWN?
To cool the brain
Scientists believe that we yawn to cool an overheated brain. The deep inhale stretches lung tissue and helps move cerebrospinal fluid, acting like a natural reset button for our brain’s temperature.
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When we yawn, we breathe in deeply, which increases blood flow in the veins of your brain and allows cooler air in.
To promote wakefulness
The electrical conductance of our skin also increases when yawning, similar to the effects of caffeine. Since caffeine promotes wakefulness , researchers summarise that the similar physiological response may indicate that both serve the same function.
To release the built up pressure in ear
Yawning helps open the Eustachian tubes, which connect your throat to your ear. This action can help relieve the uncomfortable pressure buildup that occurs when the ear does not have time to equalize, such as when a plane is landing. But since swallowing achieves the same purpose, scientists do not believe that this is the primary reason we yawn.
Due to drugs
In rare cases, yawning can also be caused by certain drugs, including antidepressants, opioids, dopaminergic drugs etc. People with sleep disorders like insomnia or obstructive sleep apnea (OSA) are also more likely to experience excessive yawning.
IS EXCESSIVE YAWNING HARMFUL?
Excessive yawning may be caused by damage to the parts of the brain which are involved in yawning. Too much yawning can also be signs of neurological conditions such as Stroke, Parkinson’s disease, Epilepsy, Migraine, Multiple sclerosis and Brain tumour.
WHY IS YAWNING CONTAGIOUS?
This is related to a phenomenon called social mirroring, where organisms imitate the actions of others. Other actions such as laughing also falls in this category. This behaviour is linked to the mirror neurons in the brain.
Zhou-Feng Chen, director at Washington University’s centre for the study of itch has conducted research on social scratching in mice. When he showed a video of one mouse scratching itself to other mice, the mice began their own scratching within 5 seconds. Chen said that when animals mimic others, they must be recognising a useful behaviour. Without thinking, their brain decides that this behaviour must be useful so they must do it as well. This also happens in humans.
Studies have shown that people are more likely to yawn in response to the yawns of kin and friends compared to acquaintances and strangers.
This social reflex is seen in animals as well. Domestic dogs can catch yawn from humans, and they are much more likely to yawn in response to their owner’s yawns than those of strangers.
So, how many times have you yawned while reading this article?
