Why is it that if I unexpectedly wake up in the morning (that is, a loud noise wakes me before I would normally get up) I can go back to sleep with relative ease if I don’t open my eyes, but once I open my eyes I’m unlikely to get back to sleep no matter how tired I am?
WAG/Bump:
I’m betting it has to do with how much of your brain is being stimulated. We have an appreciable chunk devoted to hearing, and it may or may not continue to be stimulated after the noise that woke you. But once you’ve opened your eyes, you’ve booted up the biggest chunk of brain dedicated to sensory input, and unlike your ears, the stimulus will keep on coming and demanding higher interpretation as long as your lids remain open. The longer you keep 'em open, the more parts and the more active other regions become, thereby whisking you futher and further (farther & farther?) away from that peaceful realm of somnambulistic bliss…or something.
Have I mentioned lately that I’m an idiot?
WAG/Bump the second
Often wondered this myself. I have a helluva time falling to sleep. Usually it takes at least an hour from the time I climb into bed until I fall asleep. Yet when my alarm clock goes off I hit the snooze button and fall right back to sleep. 'Sup?