Tired? No. Oxygen to the brain? Not necessarily.It turns out that reasons for yawning are still not clear. There are sevearal theories, however.
1. To cool down the brain. One professor had subjects watch a movie of other people yawning--an activity that usually causes subjects to yawn as well. When hot pads were pressed against the head the subjects yawned more, while cold packs on the head reduced the number of yawns.
2. To get oxygen to the brain.
3. To release emotion like boredom, anxiety or even nervousness. Parachuters , for instance, are noted for yawning before they jump.
Crazy fact: yawning is very addictive, yet is based on the ability to empathize or care about others' feelings. Normal people like you or me naturally yawn when we see others do so. Autistic children, however, those noted for inability to distinguish others emotions, generally do not yawn in response to others.
