What's the name of this expression ?

This involuntary action is an expression of many different feelings. People often yawn when they don't agree with a person or when they feel bored. They may also yawn when they are angry or . Some scientists believe that yawning cools down the brain. Yawning is often followed by stretching, which may be exactly what the body needs when it is upset, bored, or nervous. Yawning is a contagious reflex. When you see someone yawn, it often causes you to yawn. In fact, just thinking about yawning can make you yawn! believe yawning is a way of showing empathy. Contagious yawning is not just a human phenomenon. Almost all vertebrates yawn. Some theories suggest that yawning helps animals stay . Yawning awakens many parts of the body, including the , lungs, and abdominal muscles. Opening the mouth wide also allows animals to bare their teeth. Next time you yawn, ask yourself this question: What am I trying to communicate?