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What Do Blind People Actually See?

nautil.us

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Re: What Do Blind People Actually See?

#91

Post by leoc »

bramd wrote: post #35

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 w…

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

Indeed! Have you ever tried something like the vOICe http://www.seeingwithsound.com/ ?

Re: What Do Blind People Actually See?

#93

Post by ygra »

V-2 wrote: post #83
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 once read about a blind guy who got his eyesight - thanks to a surgery - after a life-long blindness of about 30 years. He did see, but couldn't process visual information like a normal person (eg. he would only recognize a human face to be a human face after the person began talking)

I wonder whether that changes over time. After all, people with eyesight have to learn that as well, I guess. They just do it at the beginning of their life.

Re: What Do Blind People Actually See?

#94

Post by guard-of-terra »

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…

"one's visual field steadily contracts"

This sounds like tunnel vision. I get that when I'm not feeling well (for example, some kind of gut disturbance).

Re: What Do Blind People Actually See?

#95

Post by robhack »

gohrt wrote: post #7

Strange that the article doesn't mention the blind spot that everyone as. http://en.wikipedia.org/wiki/Blind_spot_(vision)

Mind Blown. Not by the fact we have a blind spot, but how, like in the article it's not a black zone, but really the absence of any input that the brain tries to fill in. Now I'm curious to test how the brain interpolate on this area, like trying to put different background color or texture on each side of the blindspot.

Re: What Do Blind People Actually See?

#96

Post by exch »

Having congenital Glaucoma, I've always had to live with the possibility of one day being blind. My left eye is already pretty much there.

What has always fascinated me about sight is how our brains augment and outright invent things you think you see with your eyes. It's not at all about believing what you see, but about seeing what you believe.

The Glaucoma has steadily been eating away at my retina and optic nerves over the many years. Causing blind spots to form all over my visual field. In daily life, I can't see those spots. As in, there are not actually black holes in the images I perceive. The brain somehow manages to fill in those gaps with visual information directly surrounding those gaps and combine it with what my experiences/memories tell me should be there.

It's only when I start concentrating on really small details, that these holes become apparent. Particularly when looking at small LED lights in a dark environment. The LED keeps disappearing and reappearing as I slowly turn my head in various directions. Everybody has a single blind spot like this in the center of their visual field which behaves in the same way. Imagine this, but multiplied over 60 - 80% of your visual field.

Additionally, my almost-blind left eye has caused me to lose depth perception all together. This means those fancy stereoscopic 3D things are pointless to me and one would expect I would have a hard time in traffic. Not being able to judge the distance to an oncoming car can be deadly. But again, the brain seems to draw on its memories and years of experience and somehow manages to account for the lack of depth perception. It's not perfect, but enough to cope in daily life and safely move from A to B. At least on foot, that is. I am not allowed to drive a car for obvious reasons. A moped is technically permitted, but I don't. It moves too fast for me to accurately judge my surroundings in time. The same even goes for a bicycle. I only ride those in daylight. Not at night.

As far as blindness goes, I've had this once. As a kid, I fell out of a tree and landed flat on my back. For the following 45 minutes I was completely blind. It freaked me out to no end, as I was terrified it would not go away. Luckily it did. Not looking forward to that again!

Re: What Do Blind People Actually See?

#97

Post by netcan »

There's an analogy I like to bring up. I don't remember where I heard it, but It would be great to find a better articulation, but here it goes.

Gregor Mendel is called "father of modern genetics" for his work on plant hybridization and discoveries in the area of hereditary traits. He's called that because he described "invisible factors" producing "traits." We would now say that he discovered genes and their expression.

Around the same time Charles Darwin produced his great works on evolution. He was also essentially relying on invisible factors inherited from previous generations producing discernible traits in subsequent generations. He went beyond that and hypothesized about how constant sexual and natural selection would allow certain traits to be more common in the species as a whole.

Both of these men were essentially studying and describing genes, geneplexes & DNA. But, DNA was unknown to them. They knew that traits are handed down from one generation to another. But, if you asked them what the physical form of these traits was, they would have no answer.

DNA & Genes were not observable to them. They had placeholders in their mind. I guess they new that the seed produced by the parent plant contained the traits, but they might have also used "spirit" or "essence" as their placeholder.

We are at this stage when it comes to cognition. We don't know what a thought, memory or emotion looks like. We don't know what their physical form is. We know it has something to do with neurons and the brain, but we don't really know the how and what.

There is an obvious hole in our knowledge. It' missing in discussions like this.

Re: What Do Blind People Actually See?

#98

Post by Rapzid »

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…

Perhaps it's as good a place as any to make a scientific explanation but... I can see, hear, and understand the science behind light and sound. But as I sit here and think about it there is no link in my mind between the science of light and the EXPERIENCE of perceiving a color :|

Re: What Do Blind People Actually See?

#99

Post by jarek »

pixelcort wrote: post #16
tokenadult wrote: post #14

A very interesting take on the perceptions of blind people. I don't think I am acquainted with anyone who has been entirely blind from birth (which is a rare condition of life). I know a professor of psychology (who indeed does much of his research on human visual perception)[1] who has very limited vision, and thus is "legally blind." He began life, I think, with a bit more vision than he has now, but has long been…

Originally from SF area, I have been living in Tokyo for over a year now, and since moving I rarely speak with native English speakers anymore. I've been told by friends and family on occasion my accent and grammar is slowly deteriorating.

Yes, this is common, due to lack of use. Though you should notice that you have much less trouble reading and listening than writing and speaking.

I immigrated right around the "easy"-language-acquisition barrier age and frustratingly can't speak either of my languages fully right - one because of leftover accent, one because of out-of-use vocab and grammar atrophy.

Re: What Do Blind People Actually See?

#100

Post by Gracana »

colechristensen wrote: post #70
StavrosK wrote: post #30

Earlier quoted context omitted.

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.

My brain didn't program itself for vision quite right when I was an infant due to strong nearsightedness at birth so I don't experience this effect. While the eye which is closed receives – 'less attention' is the best way I can put it – I perceive blackness in that portion of my visual field.

I have the same issue. Two working eyes, but they don't work together properly. I think I can experience the nothingness, but it takes a while to become acclimated, and I can always switch to "looking out" the covered eye.
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