Answer:
Yawn is a reflex of inhalation and exhalation that draws more oxygen into the bloodstream. A reflex is a built-in physical reaction that people often do not have control over. Researchers have found that 40-60% of people who see a picture of someone yawning will yawn themselves. Even reading the word YAWN can make people yawn. It is not clear as to why yawning is contagious.
Some of the theories related to yawning being contagious are:
- Some researchers found that witnessing someone else yawning seems to render inactive the periamygdala sections of the brain. This is a tiny part of the brain on either side of the head that helps interpret things like facial expressions. Thus a conscious response to yawning would be, “Oh, he’s tired.
- Yawning may have evolved in early man as a way to signal or set up sleep schedules. A contagious yawn meant that perhaps more than one person was tired and people should sleep accordingly.
- Since tiredness might indicate a less energetic response to danger, clearly, yawning would mean people should find shelter and get out of danger. Those who yawned and paid attention to it, may have been selected into the species because they got proper sleep and were more alert to danger.
- Scientists suggest the beginning of the yearn to yawn is unconscious. This means that the signal to yawn must bypass a response called the mirror neuron system, which would render yawning in response to someone else a conscious and imitative act. Scientists have often, in the past, suggested that the mirror neuron system causes yawning.
Next Question: Why urinating on wounds is considered to be good?
Previous Question: Why is urine usually yellow in colour?
