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What Do Blind People Actually See?

nautil.us

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Re: What Do Blind People Actually See?

#31

Post by dandelany »

hentrep wrote: post #27
Chinjut wrote: post #10

Earlier quoted context omitted.

Why should the concept of color be harder to wrap one's mind around or describe than the concept of sight itself? Or, considering any animal with any kind of sensory receptors other than those you yourself have, wrapping your mind around or describing the concept of the data produced by such receptors? [A bat's echolocatory sense, say, or magnetoception...] ["Oh, it's easy to understand the PHYSICS and BIOLOGY of col…

I suppose what I was getting at is this: How do you explain what color is to a natively-blind person in a non-mathematical, non-physics based approach? In other words, the way most of the world learns about color (qualitatively). You can't use words like "shade" or "hue", because the very definition of those words are themselves tied to color. For example, attempt to describe a baseball. Descriptions invoking roundne…

I've thought about this before, and concluded that the best analogy to draw would likely be that of sound pitch or timbre.

When a sound is close to you, it seems louder. When it's far away, it seems quieter. But sounds have other qualities which are perceived the same regardless of distance - pitch being the most recognizable. And a sound's pitch changes how you perceive it unconsciously - that is, there is a "qualia" to hearing a low sound vs. a high sound that cannot really be explained.

Similarly, visible objects which are close appear larger and those far away appear smaller. But visible objects have other qualities which are perceived the same regardless of distance - namely color. And an object's color also has a certain "qualia" that unconsciously affects how you feel about it.

This has the added advantage of making it easy to explain Doppler shift vs. redshift :)

Re: What Do Blind People Actually See?

#32

Post by dkresge »

I was born (40 some odd years back) with an underdeveloped optic nerve in my left eye. An early surgery for Amblyopia corrected my gaze, but those first years of wearing a patch over "my good eye" resulted in nothing more than a lot of stress for my folks. And while I attempted to explain what I could see (are they shadows?), I never really had an answer as to why I could count "how many fingers" someone was holding up. Curiously, it was only within the past few years that I realized my left eye renders what one perceives peripherally. Hold your hand to the side of your head -- it's there, but do you really _see_ it? I can't imagine putting blindness into words.

Re: What Do Blind People Actually See?

#33

Post by titter »

sillysaurus3 wrote: post #28
gliese1337 wrote: post #6

Earlier quoted context omitted.

I am not blind, but I do occasionally get migraines with visual auras, as do my wife & mother. Exactly once in my life that I recall, I had a migraine that caused total perceptual blindness (oddly, this has also happened exactly once to my wife, before we knew each other). It's extremely odd- one's visual field (at least in our cases) steadily contracts, until there's just nothing left. It's not an annulus of darknes…

It's extremely odd- one's visual field (at least in our cases) steadily contracts, until there's just nothing left. It's not an annulus of darkness closing in, it's juts nothing- the field you can see is smaller, and there's still nothing outside of it, just like there always isn't. This is the first time I've heard of anyone else experiencing this phenomenon besides myself. Have there ever been any long-term effects…

I don't want to give a medical diagnosis, but this sounds familiar to me as a migraine sufferer.

You might be experiencing a migraine without headache: https://en.wikipedia.org/wiki/Acephalgic_migraine

Re: What Do Blind People Actually See?

#34

Post by quantumet »

sillysaurus3 wrote: post #28
gliese1337 wrote: post #6

Earlier quoted context omitted.

I am not blind, but I do occasionally get migraines with visual auras, as do my wife & mother. Exactly once in my life that I recall, I had a migraine that caused total perceptual blindness (oddly, this has also happened exactly once to my wife, before we knew each other). It's extremely odd- one's visual field (at least in our cases) steadily contracts, until there's just nothing left. It's not an annulus of darknes…

It's extremely odd- one's visual field (at least in our cases) steadily contracts, until there's just nothing left. It's not an annulus of darkness closing in, it's juts nothing- the field you can see is smaller, and there's still nothing outside of it, just like there always isn't. This is the first time I've heard of anyone else experiencing this phenomenon besides myself. Have there ever been any long-term effects…

http://en.wikipedia.org/wiki/Aura_(symptom)

It's a grab bag of weird perceptual effects that can precede migrane attacks (and apparently epileptic seizures), and they can be very disconcerting if you don't know about them.

In my case (only had them once or twice), I experienced the same visual field disassociation as you did (in addition to the scintillating scotoma thing) - I could see individual things in my field of view just fine, but I could not properly combine the whole scene into a whole. Like looking at a cubist artwork - each part is reasonable but the whole doesn't fit together, or had parts missing (not holes, just discontinuities). Of course, very shortly after that started, the migrane headache arrived.

Might want to consider talking to a doctor about it; while AFAIK auras are harmless if a bit scary, if you don't have them associated with a known issue like migrane headaches, might be good to try to find out where they're coming from. Not that anyone really seems to understand the mechanisms involved.

Re: What Do Blind People Actually See?

#35

Post by bramd »

First of all, be aware that the group that's actually totally blind is relatively small. Most people who are legally blind have some form of light perception, or can see something. I've been totally blind since birth.

Blind people can have a good or bad sense of direction, just like their sighted peers. I think the device described in the article might be more useful on short distances and less relevant for knowing where your home is while you're far away from it. This because blind people don't have the visual queues to determine if they're walking in a straight line for example. Getting immediate feedback could help with such skills and learn them how to verify the signals from the device with other senses.

Sensory substitution, aka how to replace input from one sense with input from another is a quite interesting topic.

Re: What Do Blind People Actually See?

#36

Post by LeoPanthera »

hentrep wrote: post #27
Chinjut wrote: post #10

Earlier quoted context omitted.

Why should the concept of color be harder to wrap one's mind around or describe than the concept of sight itself? Or, considering any animal with any kind of sensory receptors other than those you yourself have, wrapping your mind around or describing the concept of the data produced by such receptors? [A bat's echolocatory sense, say, or magnetoception...] ["Oh, it's easy to understand the PHYSICS and BIOLOGY of col…

I suppose what I was getting at is this: How do you explain what color is to a natively-blind person in a non-mathematical, non-physics based approach? In other words, the way most of the world learns about color (qualitatively). You can't use words like "shade" or "hue", because the very definition of those words are themselves tied to color. For example, attempt to describe a baseball. Descriptions invoking roundne…

Assuming they can still hear, I would probably try to explain the colour of light to be analogous to the pitch of sound.

Re: What Do Blind People Actually See?

#37

Post by titter »

gliese1337 wrote: post #6
jareds wrote: post #2

As someone who has been blind since birth this is accurate. I know that people who go blind later in life continue to dream in color since they have the memory of color to reference while I do not. I wonder if someone who goes blind later in life experiences things differently, possibly by automatically filling in what they assume they would see based on what they know of there surroundings from there other sences.

I am not blind, but I do occasionally get migraines with visual auras, as do my wife & mother. Exactly once in my life that I recall, I had a migraine that caused total perceptual blindness (oddly, this has also happened exactly once to my wife, before we knew each other). It's extremely odd- one's visual field (at least in our cases) steadily contracts, until there's just nothing left. It's not an annulus of darknes…

I also have had many migraines with visual aura, and have exactly one similar experience of perceptual blindness.

Re: What Do Blind People Actually See?

#39

Post by jsmeaton »

StavrosK wrote: post #30
GabrielF00 wrote: post #17

Earlier quoted context omitted.

I've been blind in my left eye since birth and kids often asked me what I saw, assuming that it was just blackness. In my case if you shine a flashlight in my left eye at the right angle I can see a flash of color, but otherwise there's just no perception at all. It's probably worth clarifying what we mean by blind. The article and the parent comment are talking about having no light perception at all. However, many…

I've heard it described that blind people see what we see out of our left eye when we only have our right eye open. It's not blackness, it's just no perception.

I've been struggling to comprehend what "nothingness" would look like, but I think this comment has helped. It's very hard to imagine pure blindness.

Re: What Do Blind People Actually See?

#40

Post by bashinator »

steffan wrote: post #12

> “When the belt experiment was over, Wächter felt lost” It seems slightly cruel to me to give someone a device to augment their senses without some provision for them to continue using it if the experiment is successful. I suppose it's also possible that Wächter didn't want to continue using / being reliant upon the belt despite the loss of the spatial sense it had provided.

I recall reading quite a while back about these ethical considerations - I'm pretty sure the ethics have been better taken into account with subsequent experiments.
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