Via Slashdot, I just read an interesting article about “blindsight” and our various visual systems. It turns out that people whose visual cortexes (cortices?) have been destroyed by accidents are still able to walk through obstacle courses — without any kind of help from canes or sounds — because their eyes and nerves still work and because our brains have another system that processes visual information, and which the info goes through before it reaches the visual cortex. This subcortical system is apparently some kind of quick and dirty information collector, which tells stuff to our reflexes. So it makes these visual cortex-blind people able to avoid objects, dodge things, and cringe from hostile faces. (I think we should call it “dangervision”, don’t you?)
Now… I’m starting to wonder if this parallel visual info system in our brains is responsible for some of the odd phenomena we experience. “Something looked strange, but I couldn’t tell what it was” sounds like it might be coming from just such a quick and dirty dangervision center. Dangervision might give you a “bad feeling” about somebody, because it caught a nasty micro-expression that your slower, high-definition regular visual cortex missed. It might even be responsible for making people think they’re “psychic” or have really smart subconscious minds, when in actuality they just have really hyper-efficient dangervision centers in their brains.
One interesting consequence of blindsight that’s mentioned way down in the Slashdot comments is that ordinary people can learn to use this facility to avoid things in fairly dark areas. The trick, apparently, is to trust your instincts.