When you see the other person yawning in the room, your instinctive response is to yawn too. However, it doesn't mean you are fighting with the urge to sleep. Scientists discovered that yawning is a process that protects our brain from overheating and serves as an alert signal to others.
Andrew C. Gallup and Gordon G. Gallup, Jr., researchers from University at Albany studied yawning in college students to find out the reason of yawning. They disproved the theory that yawning results from the lack of oxygen. As experiments showed, the alterations in oxygen and carbon dioxide levels in the blood didn't affect the yawning reaction.
In fact, yawning was found to serve as a brain-cooling mechanism. In the course of the day, our brain heats up as it burns as much as third of all the calories we consume. In order to function more efficiently, the brain needs to be cooled down. Thus when a person yawns he or she instinctively increases blood flow bringing cool air.
During the experiment, students were watching video tapes showing people yawning. Half of the volunteers were asked to breathe through their mouth and the other half was asked to breathe through their nose. As a result, those who were breathing thought their nose didn't yawn, while the rest had an urge to react with yawning.
They also performed another experiment, where students were given a cold pack to hold to their forehead. None of them yawned unlike those who held warm pack.
Experiments showed that brain cools down through nose breathing as it delivers cool blood to the brain. Additional cooling of the head brings in the same effect that's why people do not feel the need to yawn.
Contrary to popular belief, yawning doesn't imply that a person wants to sleep - it may only eliminate the urge to sleep. Researchers also explained the phenomenon of the "contagious yawning" saying that we tend to yawn looking at other person yawning because it draws our attention and this helps the group to stay aware of signs of danger.
Powered by www.infoniac.com.