There are many mysteries about the human body, and yawning is no exception. We usually think of yawning as an indicator of tiredness, boredom, or sleepiness, and the most confusing part about yawning is that it is contagious.
Why do we yawn?
Experts classify yawning into two types:
- Spontaneous yawning, which experts call spontaneous yawning
- Yawning that occurs after seeing another person yawn and which experts call contagious yawning
However, whether it is spontaneous or contagious, why do we yawn?
To date, scientists have not been able to pinpoint the exact causes of the yawning. However, some theories suggest that yawning helps:
- Regulating brain temperature
- Awaken the body
- Bring more oxygen into the bloodstream
- Keep your lung tissue moist
Your brain works best when it has an ideal temperature. When your brain is warm, for example, cognitive performance can be affected. As a result, your body has many ways to respond to changes in temperature, such as sweating or shivering, widening or narrowing of blood vessels, and stimulating behaviors that cause you to seek cooler or warmer air.
The thermoregulation theory of the brain suggests that yawning is another mechanism to help cool your body, specifically, to calm your mind.
A body of research supports this theory. Not only have animal studies shown that yawning is often preceded by a rise in temperature in the brain and followed by a drop in temperature, but there is also an association between the ambient air temperature and the likelihood of yawning. The overall theory is that given that the air temperature around you is ideal, yawning can help cool your mind.
Why is yawning contagious?
Similar to the mystery surrounding the causes of yawning, experts also aren’t really sure why yawning is contagious.
Spontaneous yawning is known to be an ancient, evolutionarily conserved behavior in the mind.
In the context of the theory of brain cooling to yawn, yawning may have evolved into contagious as a means of increasing cognitive performance and alertness of people within a group. While this may sound silly in today’s world, it may be group behavior.
However, those who reject the physiologically related yawning theory still believe that the behavior has been sustained throughout evolution due to its social influence.