Yawning:

Contagious yawning occurs in humans in response to thinking, seeing and hearing another organism yawn. Contagious yawning differs from spontaneous yawning that happens when you are bored, stressed or feeling sleepy. Although contagious yawning begins in early childhood, spontaneous yawning starts when an infant is in the mother’s womb. While it’s not clear why some individuals are more susceptible to contagious yawning, researchers are yet to provide an explanation why we yawn and what our bodies achieve after yawning. The eBook vividly demonstrates why a child yawns when he/she witness her mother or a close relative yawn. Despite the fact that yawning is an irritating behavior, chapter 3 outlines how yawning can help relieve stress.