I wondered about this since elementary school. Surprisingly, no one has ever been able to give a 100% accurate answer since. I'm not referring to staring at something on purpose.... i'm referring to when all of a sudden, your eyes get fixed on something for about a minute or so, and you just gaze. I've always thought of it as the biological equivalent of yawning for the body, except it's for the brain instead. The brain's equivalent of yawning??