Tell me why we yawn?

Yawing can be contagious. Just thinking and reading about yawing makes us yawn. It may surprise us but, apart from babies, kids, teenagers, adults; even some birds, reptiles and most mammals also yawn.

However, the reason why we yawn is a bit of a mystery, though many people presume that humans yawn because our bodies are trying to take in more oxygen and get rid of extra carbon dioxide. There is also very little research about yawning because it is not a problem for most people.

Did you know these facts on yawning?

• The earliest occurrence of yawn happens in humans at about 11 weeks after conception (i.e., before the baby is born)
• Average duration of a yawn is approximately 6 seconds
• A part of the brain that plays an important role in yawning is the hypothalamus ( Research shows that some neurotransmitters and neuro-peptides increase yawning if injected into hypothalamus of animals)
• Yawns become contagious to people between first and second years of life

For most who believe, human yawn because they need more oxygen and try to get rid of extra carbon dioxide, the theory makes some sense. According to this hypothesis, when people are tired or bored, they breathe more slowly and as breathing slow down, less oxygen makes it to the lungs. This builds up carbon dioxide in the blood, a message is sent to the brain, which signals back to the lungs to take a deep breath,” and a yawn is produced.

Did you know? You yawn when you are bored. Scientists confirmed this observation by comparing the number of yawns in some students ( in their late teens) who watched interesting music videos to the number of yawns in students who watched an uninteresting TV programme. As expected, people who watched uninteresting TV programme yawned more ( 5-6 yawns in half hour) than those who watched interesting videos (3-4 yawns in half hour).

Yawning and stretching increase blood pressure and heart rate and also flex muscles and joints. Evidence that yawning and stretching may be related comes from the observation that if you try to stifle or prevent a yawn by clenching your jaws shut, the yawn is somewhat “unsatisfying”. For some reason, the stretching of jaw and face muscles is necessary for a good yawn.

It is possible that yawns are contagious because at one time in evolutionary history, the yawn served to coordinate the social behavior of a group of animals. When one member of the group yawned to signal an event, all the other members of the group also yawned. Yawns may still be contagious these days because of a leftover response (a “vestigial” response) that is not used anymore. None of this has been proven true and yawns are still one of the mysteries of the mind.