Yawning is common in almost all the animals with spines. And all of them have their specific uses of it. Penguins yawn for mating, snakes yawn as an exercise for their jaws after a meal and some animals like guinea pigs use it to express anger.
The question is, why exactly we, the humans, yawn? And can yawning be considered contagious?
If you’re a human, then you may have yawned at the title of this article. Though the reason for yawning is still unknown, it may be related to brain development. It was commonly thought that in adults yawns were for drawing a larger quantity of oxygen into the lungs to reduce the feelings of tiredness. However, a recent research suggests that this may not be the truth and that yawning has developed as a way of cooling our brain physiologically. Like a computer, an average brain is at its best at a certain temperature, and thus, tries to avoid “overheating”. Yawning causes an increase in the heart rate, blood flow and the use of muscles in your face, all of which have an important role in cooling the brain. Furthermore, inhaling cold air can help change and maintain the temperature of the blood in our brain.
Why does our brain get hot?
The fact is, exhaustion and sleep deprivation are the factors which increase the overall brain temperature, which is the reason for why we mostly yawn more in these states. Researchers found that participants who placed warm packs on their heads yawned more while watching others yawn compared to the participants with cold packs on their heads. This means that you’ll yawn less if your head is cold.
What causes Contagious yawning?
Contagious yawning starts in children of ages around 5. This is when empathetic behavior and the ability of the identification of emotions, starts its development. Researchers believe that you copy the yawns of people who are genetically or socially close to you, more than others. Dogs are also believed to copy the yawns of their owners, more, than of a stranger. And finally, there are mirror neurons in our brain, which respond when we perform certain actions, see someone else doing those actions or just hear someone talk about them. They cells are important as they are essential for self-awareness and learning. When we see someone else yawn, inside our brain the mirror neurons get activated, and this results in the copying of the yawn.
Yawning may occur in people whose heads are hot (literally) and at the same time social yawns allow us to stay good with people.