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Medical Visual Sensory blank-outs ?

  1. May 18, 2008 #1
    Visual Sensory "blank-outs"?

    Is it true that if you attempt to visually perceive something that is so strange and beyond your personal understanding, you will not be able to "see" it? In other words: If your brain doesn't already have that particular image stored somewhere and you try to view something that fits the image, will you simply not be able to visually sense it?
    I ask because I have read claims that the natives were unable to see the ships that Christopher Columbus and his crew sailed in on....they could see the water being displaced by something, but they didn't know why until one of the smarter natives explained the presence to the others. Would this make us a more vulnerable species than those with enhanced perception....like dolphins?
     
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  3. May 18, 2008 #2

    DaveC426913

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    I think that is nonsense.


    I should clarify. I think it is nonsense that they would see the effect on the water but not the ship. I do however think it is possible that the natives did not understand what they were seeing in the sense that they may not have realized that those shapes were large shapes - large enough to hold many people. I think it is marginally plausible that they may have thought the ships were small but very nearby.



    I do know that I've experienced something like thyis myself - briefly. I've seen things that made no sense in my vision and my brain made the best of what it could - you know, like seeing a spider hanging from my hat on my head. My brain didn't interpret it as a tiny shape two inches away, it interpreted it as a very large shape many yards away (no I didn't poo myself thinking I'd seen a giant spider...). It only lasted a few moments.

    I've had other, similar experiences where my mind can't process what it sees right away and for a brief moment I think I'm actually seeing something that my rational mind knows cannot exist. Maybe a set of lights floating in the sky or something. The illusion lasts long enough for me to think to myself "well, that's just silly, there's got to be some logical explanation" before I realize what I'm seeing is just some reflection or trick of the eye.
     
    Last edited: May 18, 2008
  4. May 18, 2008 #3

    DaveC426913

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    Certainly. Humans have put almost all their eggs in one sensory basket. I've often marvelled at how cats and dogs aren't fooled by mirrors or photos for very long. They seem show little interest in visual images that have no smell.
     
  5. May 19, 2008 #4

    Danger

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    As for the native thing about the ships, the Incans thought that the Spanish conquistadors were centaurs, because horses didn't exist in the western hemisphere. A human riding on the back of an animal was such an alien concept that they just couldn't absorb it.

    The dog/cat/mirror thing appears to be a result of most animals not having a sense of 'self'. Apparently, cetaceans and some primates seem to realize that the reflection is 'them'.
     
  6. May 19, 2008 #5
    Hallucinations are kind of like this... Visual gets whacked/blacked out. I've always assumed
    it was related to receptor interference of some sort.
     
  7. May 19, 2008 #6

    DaveC426913

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    I was really talking more about dogs/cats realizing that the dog/cat-shaped thing is not a "real" dog/cat at all. They are not fooled easily by optical illusions because their sensory array is much wider - sight takes a back eat to smell.
     
  8. May 19, 2008 #7

    Danger

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    Sorry; I mentally combined a couple of different posts and therefore read more into yours than was intended. I fully agree about the sensory matter. I've never had a pet that would pay any attention to a mirror after an investigatory sniff (except for W's budgie).
     
  9. May 19, 2008 #8

    DaveC426913

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    Makes sense. Birds (both predators and ... seedivores) use their vision far more than smell.
     
  10. May 19, 2008 #9
    put in this context, that makes complete sense. it's like seeing the squiggly line in the corner of your eye...perspective is everything if you rely solely on vision to interpret your surroundings. i would guess that a majority of the natives didn't have much to base logic on though, without any knowledge of radiant energy and how our cerebral cortex works with our eyes

    i sometimes forget that the earth was still flat for most at this point
     
  11. May 22, 2008 #10

    Moonbear

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    Yes, I've experienced things like that too, where I just couldn't make sense of what I was seeing, and thought it was something entirely different. Yes, I still saw it, but my perception of just what exactly I was seeing was rather odd. The clearest example I can recall was staring out over a large body of water on a dark, slightly foggy night, and seeing something red in the distance. At first, I thought I saw a ship's port side running lights. Then the redness increased and grew larger. Hmm...the person I was with was staring with me and neither of us could figure it out. More lights, maybe a cruise ship? Nope, as it came "closer" it took on more of a spherical shape. What the heck sort of vessel was it? But, we waited to see if it came close enough to figure out. Then realization dawned...it wasn't going to get much closer than...384,000 km! It was the moon, low in the sky, very red looking, and covered by clouds so only little patches of light were showing through the clouds and fog. As the cloud cover or fog moved, and the moon rose, because we had seen so little of it, we had the perception it was an object moving closer to us over the water. Visual perception is rather interesting.

    So, yes, I would agree with DaveC that it's quite within the realm of possibility that they saw the shapes, but without a context to interpret them, could not determine what exactly they were until they were much closer.
     
  12. May 22, 2008 #11

    DaveC426913

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    Heh. I just realized I placed my own assumptions on the story, making more of it than there had to be.

    I interpreted the ships as being quite close, like less than a mile out - easily large enough to see details. I assumed that the natives could still not understand what they were seeing even with plenty of data.

    But Moonie didn't fall into that assumptive trap. If the ships were two or five or ten miles out then the story isn't really much of a story at all.
     
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