Brownian thought space

Cognitive science, mostly, but more a sometimes structured random walk about things.

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Location: Rochester, United States

Chronically curious モ..

Thursday, January 18, 2007

Why eyelids?

One of those early morning, just-awake question: why eyelids? Thoughts:
  • to block especially harsh visual input (so why not for sound or smell?)
  • as windshield wipers, with the tear ducts as the things that squirt soapy water from the nozzles onto the windshields
  • to "see" dreams better? If dreams are somehow important, and if they need access to primary visual cortices, then it might be a good idea to shut down V1 requirements through the thalamus?
Here's another thing: if you flash a bright white light onto closed eyes, you see red (not literally, unless you weren't expecting it), which means that eyelids let red frequencies through, which in turn means that they don't let blue through. Now isn't that just neat: moonlight or nighttime light sources in general - the natural ones, not flashlights - tend to be blue, so our eyelids are actually not just filtering out light in toto, but specifically those bits that are most prominent during the night time. Neat! Question: is there a relationship between the size of the visual cortex and the kind of eyelids and what they can do?


Blogger Albert said...

I've another comment for your list. we need eyelids to cover our eyes when we sleep, not so much for our own sake, but because people who sleep with their eyes open look extraordinarily creepy. Ugh. Had an ex-boyfriend who used to sleep with one eye closed and the eyelid on the other peeled back. Nasty.

Nice blog by the way. Especially like the pictures of vegetables.

January 19, 2007 12:59 PM  
Blogger Mohinish said...

Looks like I've missed previous comment(s) ;) Apparently fish never blink. They also don't have eyelids. Good thing you don't date fish. And while on the topic of fish and dating, I just found out that in Minnesota and Texas (according to that reliable information storehouse, the WWW), it's illegal to have sex with a fish.
PS: Mo is fine by me :)

January 19, 2007 1:27 PM  

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