Yawn
reflex / From Wikipedia, the free encyclopedia
A yawn is a reflex. It involves a large, long taking in of air, the stretching of eardrums as the jaw opens wide, and last a (sometimes loud) breathing out. Pandiculation is the act of yawning and stretching simultaneously.[1] It is easy to see when someone is yawning, but no-one knows what its function is.
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Yawning is commonly associated with tiredness, stress, overwork, lack of stimulation and boredom. In humans, yawning is often triggered by others yawning (e.g. seeing a person yawning, talking to someone on the phone who is yawning) and is a typical example of positive feedback.[2] This "infectious" yawning has also been observed in chimpanzees and dogs.[3][4] Cats both yawn and stretch, though not necessarily at the same time.