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What Do Blind People Actually See? (nautil.us)
304 points by dnetesn on Aug 13, 2014 | hide | past | web | favorite | 118 comments

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 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. Like what the back of your head looks like, as the article says.

In the end, you literally see Nothing. It's truly bizarre[1]. It's not an experience I particularly want to repeat, but I'm kinda glad it happened just once, for the empathy value. It's not really something that can be effectively described if you haven't (not) seen it yourself; even now, I have trouble re-imagining the experience, 'cause my memory wants to fill in blackness or grayness or whatever. But at least in theory I now know exactly what the Nothing from _The Neverending Story_ (doesn't) look(s) like. :)

[1] What makes it even more bizarre is that migraine blindness is a strictly neurological effect- there's no damage to your eyes or optic nerves- which means you can get temporary blindsight. In my wife's case, this meant she managed to walk a couple blocks home from a friend's house, crossing suburban streets and so forth, totally normally, while all the while convinced that she was completely blind. Which, as far as conscious perception goes, was the truth!

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 on you?

Mine is slightly different. I don't have migranes, for one. Also, in addition to experiencing exactly what you described (minus the migrane), sometimes I experience the inverse: I can no longer see whatever I look at, but I retain peripheral vision. For example, if I were to look at the "o" in the word "for," I wouldn't be able to see the entire word. I could still read, with difficulty, until the effect became so strong that reading was impossible. (I still had peripheral vision, sort of, but eventually paragraphs became unseeable rather than individual words.)

Whenever any of these things occurred, I was completely normal again within two hours. It was bizarre, and it's mystified myself and two eye doctors. It's only happened less than a dozen times, but it's been happening since I was very young, and my most recent was less than a year ago.

The "blindness" was exactly as you describe: not a blackness, but a nothingness.

Do you happen to have any more info about the condition? It's very elusive.


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.

I get the blindness aura thing just before I have a migraine (which doesn't happen much anymore since I stopped accidentally suffocating myself with my pillow..).

The experience for me is absolutely identical to that of a blind spot optical illusion, except bigger and in a different area (just a bit off from the center). It's not generally obvious that there's an issue, the brain fills it in, but if I put text in that part of my vision I'll notice I can't actually read it.

I suffered something similar, just once, about twenty years ago, in high school, and never since. Although, instead of an impression of nothingness, it felt more like a Photoshop content aware fill, similar to the optic nerve blind spot, but moved to the fovea.

I was walking the hall to my first period, mainly looking at the bland floor tiles, and didn't realize anything was abnormal. When I happened to look up at the faces of fellow students, I noticed they had no faces, just skin colored smoothness. My hands, and text on the posters on the walls appeared in my peripheral vision, but as soon as I looked directly at anything, it seemed to disappear into an average of it's surrounding colors. I didn't freak out, but calmly walked to my first period, where I was scheduled to take a test. I made way to my desk, and marveled at this oddness, but didn't say anything, until the test was passed out and I could tell it was a page of text, but, of course, the words disappeared upon inspection. I was really impressed how useless my peripheral vision was in dealing with text or faces.

I had an awkward conversation with the teacher, who I feared thought I'd invented a disorder to get out of the test, before being allowed to visit the nurse.

The condition lasted maybe an hour. The ophthalmologist I saw shortly after found nothing wrong with my retinas or eye pressure, and declared it a visual migraine and let me go, with a newfound empathy for those with macular degeneration.

The content-aware fill is what I get as well -- I have some permanent blind areas in my right eye due to optic nerve damage; I lost a lot of peripheral vision, but also the normal optic nerve blind spot is quite a bit larger in that eye -- about 1/4 of the height of my visual field, and half as wide -- fortunately still not affecting the central point of focus.

Obviously no black patch or anything like that; I first noticed the missing section (before I had visual field tests done to detect it properly) while driving, stopped at a light; I rubbed my other eye momentarily, and the traffic light vanished.

I also suffered something similar on multiple occassions in my late 20s and early 30s - growing rainbow zig-zags accompanied by graduals loss of vision in both the center of my field of view and edges of my peripheral vision, although never to the point of total blindness. Incidents would last between one and two hours. But, after several ophatmologist and visits to other physicians, I finally found the trigger: it happened roughly 18 hours after consuming 2 or more glasses of absinthe. Stopped drinking absinthe, haven't had an aura in years.

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

I'm sorry to hear that. My wife has a rare brain disease and unfortunately, it's something she's all too familiar with. If it's happening to you without corresponding migraines (or even with), see a neurologist, there may be something wrong. Her neurologist regularly sends her for opthalmologist exams just in case and they never find anything wrong.

Thank you for the info. May I ask, which disease?

Intracranial hypertension.

Hey, I had that about twenty years ago. The only symptom I had was that I would wake up with a headache for no apparent reason (not a migraine, but frequently nausea-inducing).

My ophthalmologist detected it during a regular examination and sent out for MRI/CAT scan/spinal tap to rule out everything else, then put me on a regimen of -- oh, now I can't remember; the medicine used for altitude sickness (diamox?) and eventually "cured" me; I haven't had a recurrence since.

I guess my point is that the grandparent poster should consider seeing an ophthalmologist and/or a neurologist at their earliest convenience. (My doctor was pleased that he'd "caught it in time"; he spoke of another patient in which it had not been detected quickly enough and that person had gone blind.)

You mentioned "eye doctors," but have you seen a retina specialist? I've temporarily lost sight twice, but in my case it is like having matte grey construction paper cover part or all of my vision. My retina specialist has found a couple of issues.

No long-term effects that I know of, aside from the simple on-going fact that I have migraines; they didn't get any worse or more frequent after that, nor have I since developed any other visual or neurological symptoms. As it happens, I don't get migraines very often- once or twice a year. My wife & mother both get them on a much more regular basis, once or twice a month.

The loss of foveal vision or random patches of the visual field (as opposed to gradual-leading-to-total elimination of the entire visual field) is something I have encountered a few times. As quantumet noted, auras are kind of a grab-bag, different people can have wildly different kinds of visual distortions, and some migraine sufferers don't have them at all. I know one who gets aural (hearing) distortions instead; meanwhile, I don't get any hearing issues, and my wife becomes hypersensitive to sound but doesn't experience distortion.

Migraines, generally, like seizures, are a result of mis-fires in your brain (super simplified explanation, of course). Essentially, something goes wrong such that your brain just decides that it is in pain for no particular reason (although there are triggers, just like there are triggers to epilepsy, that set of just the wrong cascade of neurons). Auras are just another manifestation of the same thing- if the thing that goes wrong goes wrong in or near your visual cortex, you get visual distortions in addition to the pain. Eventually, your brain resets, and then things are normal again, until your brain (metaphorically speaking) tries to read out-of-bounds memory, or goes into an infinite loop, or whatever else it is (again as quantumet noted, the exact mechanism is not really all that well understood), the next time.

Side note, on how everybody's auras are a little different- we just found out about a month ago that my most common aura is blue sparkles, while my wife's is gold sparkles. We knew that we both commonly saw sparkles, just never happened to mention the color before. Also incidentally, I do get auras much more often than I progress to a full-blown migraine headache.

Since the problem is neurological, eye doctors generally won't be able to figure it out or do anything about it. Generally, because eye problems can be migraine triggers. My wife starts getting headaches if she leaves her glasses off too long, and one of the first things to check when migraine frequency increases is whether her prescription has gone out of date. Other triggers are dehydration (for her) hunger (for both of us; this is a problem for me because I don't get hungry normally, so sometimes the first indication that I need to eat today is the onset of a headache) and sleep deprivation (for both of us).

That sounds like an ocular migraine. They don't always include headaches. Both my wife and I have experienced this.

Some of the migraine aura symptoms are terrifying. My ex temporarily lost the ability to remember most words, including "door". Even after being told them, they were gone again seconds later.

I got that on occasion (though infrequently) and it's usually after prolonged sleep deprivation.

For me this is a symtom of heat stroke, usually the first I notice.

I've had a few auras, and my experience was different. There was an ever increasing spot of vision missing, which came to engulf half my vision, but of course I'm aware that the missing part is cutting into my field of vision; I could still map the places in the field of vision where I should see external objects, and imagine something superimposed there. I would say that it was similar to (but eventually larger than) the natural blind spot that occurs where the optic nerve meets the retina. There is no specific color there (it is not black), but we know that an object which should be seen has disappeared because of that spot, and we can imagine that it ought to be there.

I'd like to add that I had a recent recurrence of an aura, after some twenty years! It did not precipitate in a headache, and it was the type with a zig-zag edge surrounding the blind spot: an edge of shimmering color. After it came and went, I prepared myself for a headache, but it never happened.

"scintillating scotoma" is the one with the shimmering edge. I've had that a couple times.

Incredible. I could never find a name for that. I used to have it in early 2Ks. I also had weird brain issues[1], and also have many floaters so I just thought it was one placed just in the worst place, causing refraction. It usually started as a small patch that gradually stretched, moving along the outer edge of my vision. As Wikipedia says, the migraine came a little after that. The last 3 pictures in the article are quite on point : http://en.wikipedia.org/wiki/Scintillating_scotoma

ps : Many thanks

[1] As far as I could search, it's close to sleep epilepsy.

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

"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).

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 think most) people who are considered legally blind do have at least some light perception. The legal standard in the US is vision that can be corrected to at best 20/200 in the better eye.

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.

That is a very interesting observation! When we close both eyes, we perceive a blackness, or perhaps some sort of reddish/purplish glow of light through eyelids, or the after-effect of light. However, by keeping one eye open, it seems any signal from the closed eye is overridden, so you really don't perceive anything there.

Agreed. Definitely just spent a few minutes contemplating if I was seeing anything through my closed left eye. It seemed as if the only way I could turn my left eye "on" when it was closed was by also closing my right eye.

I can differentiate between light or no light in front of my closed eye, even if the other eye is open. Is this the inverse effect of the effect you're talking about?

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.

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.

But that's a question of focus. If you close your one eye and ask "what do I see out of it" you get a different answer than if you don't ask the question.

Yeah, the brain just prioritizes the right eye. If you concentrate you can perceive the blackness in the left eye. That kinda leads me to wonder if eyes send a signal for black? If not and no signal is interpreted as black by the brain and your eyes are damaged then you would "see" black; even if you can't tell it because you have no point of reference?

It's the difference between int(0), None, and undefined :)

Similarly, I am almost entirely blind in my left eye and have been since birth. I have some very limited peripheral vision, but I can basically only sense light and movement in a very narrow field of view if I try very hard.

People have always assumed that what I see out of my left eye is basically what someone would see out of a normal, healthy eye with a big black spot in the middle, but that's not it. I don't see blackness, I see nothing.

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.

Yes they learn, but the opportunity might be a one off for all we know.

Not the same, but similar:

According to the Nobel Prize-winning research from David Hubel and Torsten Wiesel in the 1960s, the brain may only have a short window of opportunity in which to develop binocular vision, in which both eyes are used together. Their studies in cats, and many other studies since, suggest that if the developing brain isn’t exposed to overlapping images from the two eyes, it will never form the connections it needs to process a three dimensional scene

See the entire article: http://www.bbc.com/future/story/20120719-awoken-from-a-2d-wo...

I've always wondered how someone born blind is able to wrap their mind around the concept of color. It appears you've done so -- how would you describe color?

I don’t have any meaningful concept of color. I do have some light perception so assume that white is what I see if you shine a light in my eye, black is what I see when all the lights are turned off and gray is the middle ground when there are some lights turned on but not enough for the light to actually be painful. Intellectually I realize there are other colors but the only way I can explain them is in reference to objects. Grass is green, the ocean is blue, etc. I realize that this is meaningless since I don’t have a frame of reference to compare the ocean to grass from a visual perspective.

If you have some light perception, what happens if you shine different colors of light in your eye?

Nothing, it looks the same to me.

I suppose it is possible you're perceiving the light as a particular color, but if you can only perceive that color you would mistaken it for white?

I don't know what jareds's situation is, but normal humans have light sensors that are not color sensors, and also have color sensors


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 color, but can the blind really comprehend the EXPERIENCE of color?", some might say. Alright, fine, shades of "What Mary Didn't Know", but I'm not keen to get into that.]

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 roundness and texture can be easily understood because the individual retains his/her sense of feel. But saying "it's white in color... white is actually the presence of all colors..." obviously doesn't work.

I'd be curious to hear an example of how you would explain color to someone who has been blind for life.

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 :)

Try looking into qualia. http://en.wikipedia.org/wiki/Qualia

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 :|

This was touched on in The Giver, interestingly. The main character becomes able to see color after never having been able to.

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

I imagine a blind person can study light just as well as anyone else, and can learn about the eye and can understand that sighted people are able to detect both wavelength and intensity differences. Just like a deaf person could learn about pressure waves in the air and how they can be detected by functional ears.

But it's probably difficult or impossible to understand what the perception is like, and how rich it is, except by analogy when thinking about how they'd try to describe the senses the do have to someone that doesn't have them.

Our understanding of echolocation in bats or the magnetic field in birds is probably similar. We understand what they detect and how they detect it. But I don't think we have any understanding of what it's like to experience that perception.

There's a classic essay by Thomas Nagel that makes this exact point in great detail: "What is it like to be a bat" http://organizations.utep.edu/portals/1475/nagel_bat.pdf

This reminds me of musicians, particularly those with perfect pitch, who talk of 'colours' of keys. While it's not a direct analogy, perhaps one way to think of colour, if you've never seen it before, is to think of different wavelengths of sounds being a bit like different wavelengths of light.

Also since blindness is a lack of sight as we know it, it is a very large category of phenomenon. Someone who goes temporarily blind from a blow to the head may experience something differently from someone with retinal damage. Someone who has never been able to see may experience things differently from someone who has recently suffered blindness as a result of injury or illness (and these themselves might have different experiences).

Right! I felt like no one was quite pointing this out.

Your brain is expecting certain input in given situations, and you have layers and layers of habits based on those expectations.

If you are accustomed to NOT having that input, you don't expect it. You don't fake it (imagining a black space of the size a visual field would be...), you just don't have it, and it's not a part of your interactions with the world.

If the shape of your visual field changes suddenly -- you're about to pass out and you get "tunnel vision" -- it's obvious and startling. If it changes gradually, you don't even notice; you just start hitting your head on low beams more often, or bumping into table edges as you go by, until you adjust (this is from experience...).

I am fascinated by the notion of color and tone. I suppose you're not deaf so you can feel tone (low and high pitch). I thought that these two 'abstraction' were conceptually the same and hardwired into our brain. But then there might be different roots for blindness and maybe childhood-blind people are having issues at that level (as opposed to eye / optic nerve level).

Have you considered a haptic device like the one in the article?

No. I've found that a GPS on a smart phone works fairly well for me if it's an area I am generally familiar with.

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.

> I've been totally blind since birth.

Please forgive me for the naive question, I'm probably full of misconceptions about blindness, but out of pure curiosity, how do you read and write so well without seeing? Is the technology so advanced today? Are you using a screen reader and a regular keyboard? (e.g. typing and than playing it via the reader) how do you know if you made a typo? (e.g. who's and whose sound the same)

You really didn't have any typos, and as well your indentation and styling are perfect (much better than me but I'm not a native English speaker)

Can you read and write code without seeing? Are there any blind programmers that you know of.

again asking out of pure naivety

tl;dr, I'm impressed with your reading and writing considering that you said your are totally blind, and curious how do you do it. (I always was afraid of going blind for some reason, and afraid I will never be able to write code again)

I'm not a native English speaker either.

> Is the technology so advanced today? Are you using a screen reader and a regular keyboard? (e.g. typing and than playing it via the reader) how do you know if you made a typo? (e.g. who's and whose sound the same)

Yes, I'm using a regular keyboard and a screenreader. Besides speech output I use a device called a refreshable braille display which can display up to 40 or 80 characters at a time depending on the model being used. I'm sure you will find some pictures if you Google it. However, those devices are quite expensive and many blind people just use speech output. Even with just speech there are options for reading letter by letter, word by word etc. However, I see some people make much spelling mistakes because they just listen and not rreally read how a word is spelled.

> Can you read and write code without seeing? Are there any blind programmers that you know of.

Sure you can. I make a living by programming and doing web accessibility consultancy. Another nice example is the free and open source NVDA screenreader[0], which is developed by two blind guys.

[0]: http://www.nvaccess.org/

Fascinating, thanks.

At what speed do you replay text->audio (ie realtime, 1.5x,2x,...)?

Lastly, if you disregard price is the braille 'refreshable display' a better experience?

> At what speed do you replay text->audio (ie realtime, 1.5x,2x,...)?

Approximately the speed that the guy at the beginning of this video uses: https://www.youtube.com/watch?v=92pM6hJG6Wo

> Lastly, if you disregard price is the braille 'refreshable display' a better experience?

It just what you're used to I guess, I know lots of people who can get by without one. I especially like it when doing coding and doing stuff in a terminal. Easier to see indentation, parenthesis, quotes etc.

This is awesome, thanks for the reply! p.s. are there IDEA / Eclipse plugins that support accessibility?

You mean making the IDE itself accessible? Eclipse is already quite accessible out of the box.

TV Raman has done a lot of work and storytelling relating to his blindness. He is a CS researcher at Google:


> 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/ ?

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

Yes, I have played with it. However, I'm not convinced yet if I should invest a lot of time learning it. Another useful and interesting skill is echolocation[0]. I have used that since Iwas a child to survey my environment.

0: http://en.wikipedia.org/wiki/Human_echolocation

I seem to recall research claming that vOICe users already had very impressive results after 50-100 hours of use/training, so I would guess that it's worth the time.

Human echolocation is absolutely balling, what else can I say?

A great article. I recently visited the "Blind Exhibition" in Warsaw. They show you some items that blind and visually impaired people use on a daily basis and then you have to guess what they are for. I'd never contemplated how blind people know when a coffee cup is full, or pair their socks.

They then take you into a series of rooms (bathroom, the street, art gallery, kitchen etc.) which are completely black. Not a shred of light. You are blind. I can't describe how it felt other than terrifying. I didn't know if my eyes were open or not. It wasn't the black that I saw when closing my eyes, or am sleeping in a dark room. It was this empty hollow of nothingness.

As someone who has always wondered what it's like to be blind then closed my eyes for a few minutes and stumbled around my home - it's nothing like that at all. I left having found a new sense of understanding for the struggles that blind and visually impaired people go through on a daily basis.

An interesting but harrowing statistic they mentioned at the end of our trip was that the majority of people go blind, instead of are born blind. And the main cause is diabetes. It's not uncommon that those with diabetes lose their sight and then their sense of touch. Imagine not being able to feel your way around after going blind.

I highly recommend the exhibition if you're ever in Warsaw, and I think they have it in a couple of other cities: http://niewidzialna.pl/en/

I still want that vibrating compass belt.

There's a small version that goes on your ankle, called a North Paw. Get directions or order a kit here http://sensebridge.net/projects/northpaw/

I still want to try to glue a magnet to my finger. It is possible to get implants, but that's scary. Being able to feel magnetic fields must be awesome!



If Google Glass (or its descendant) ever becomes viable, a killer app would be an augmented reality "this way is north" arrow that's always there, floating in the sky.

I've also been really interested in using one ever since reading about them last year. Seems like it'd be a good Kickstarter opportunity.

I wonder if it could be done more subtly, perhaps with a few vibrating motors embedded in the skin around one ankle.

There is something similar to this that is already reality: people use a magnet on one finger to be able to perceive EM fields.

We have the ability to turn our senses off when we are going to sleep, so any "sixth sense" prosthetics should be switchable or at least not strong enough to disturb sleep.

I think there was some work into this called "SouthPaw", to contrast with the external NorthPaw.

> “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 think the experiment was still in progress when they took it away, since they observed his reactions to this. Later they might have given him the device.

That reminds me of the experiment where someone lived with upside down goggles[1]. Just like with babies trying to understand what they see, his brain had to adapt to everything and he had to relearn to perform the actions.

I wonder how it was once he took them off.

[1] https://www.youtube.com/watch?v=-kohUpQwZt8

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.

This made me realize that while it is instinctively difficult to imagine a lack of sight or touch, a lack of sound, smell, or taste, seems relatively easy to imagine. Sight vs sound is especially interesting; we tend to think of lack of sight as blackness, as the article describes, but there doesn't seem to be an instinctive parallel for lack of sound (at least in my mind). I guess it would be "silence", but that's much more akin to lack of sound than the concept of blackness is to lack of sight (even if blackness is technically lack of light).

Although having written that, I now wonder whether a person who loses their hearing might be plagued by phantom hums or such things, as can sometimes happen to hearing people when exposed to extended silence.

For me this raises a question on a slightly different topic: if you're born deaf, what languages do you think in? I can consciously think in English and French, but if you have never heard a spoken language before, what would your thoughts be like?

I'm mostly blind in one eye. --The center of the pupil was destroyed by a parasite when I was very young, and I have no memories of normal sight. I do have some peripheral vision in that eye, but not enough to read or perform normal activities, especially because I have to turn my head to see, such as it is - I can make out certain objects and get a sense of colors, but nothing is clear - reading would be out of the question, for example.

Describing my lack of sight is difficult, because few people have the necessary frame of reference to understand. The best way I've found to describe it is to say that I can only see one side of my nose. Now, I know the other side is there, obviously, because I can look in a mirror and see it with my good eye. But without a mirror, that side of my nose doesn't exist to my vision. --There's not a dark blob or anything like that - it simply does not exist.

It also means I have no real depth perception. I have to try and estimate the distance of an object based on what I know of it's true size - when it's moving towards me, I don't get a real sense that it's actually coming at me, just that it's getting larger at some rate. Needless to say, that makes playing games like baseball very diffciult as there is not necessarily other objects around that make it easier for me to recognize the rate at which the ball is flying towards me.

Can't you move your head side to side to judge depth by parallax movement? At least a little bit?

This reminded me of the language of the Guugu Yimithirr [1] who always describe left/right/forward/back with cardinal directions. Thus, they always have a great sense of direction, and know where north is, even indoors. In that case, it's like the vibrating belt is built into the language.

[1] http://www.nytimes.com/2010/08/29/magazine/29language-t.html...

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.

This story reminded me of the guy that had a magnet implanted in his pinky finger, who was then able to sense electromagnetic fields and other stuff


Implant seems extreme. One could do well with, say, compass armbad with a strong magnet and a pokey attacmhent.

A couple of years ago I read a non-fiction book called Crashing Through[1] - about a guy who was blinded by some chemical at a very young age (<1y) and was able to have his vision restored in his 40s via a new procedure.

It went on about some difficulties he had processing the new data. His brain had to "learn" how to see. It was so difficult that he would sometimes close his eyes and and rely on his echolocation skills to navigate.

Very interesting book if you want a first hand account of what it is like to go from being blind to being able to see. (and also about being blind)

[1] http://www.amazon.com/Crashing-Through-Extraordinary-Story-D...

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.

Wow, I think you might have a very similar vision issue as I do!

Left eye as well, although my eye is healthy, it was closed when I was a baby so my vision never developed properly. Eye patching was tried on me as a kid, but just resulted in a cranky toddler me. It took years and years for me being able to verbalize what I could see out of my left eye--I basically have some limited peripheral vision and no central vision. My eye doctor explained that part of the issue is that peripheral vision primarily detects motion while central vision is for detail--so while I can detect motion and light, it's hard for me to put an image together.

I have so many memories of trying to read that big stupid E with my left eye and not being able to explain what I saw. (Um, there's a light on, right?)

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 visually disabled. In a personal conversation, he related that his originally intended research field was astrophysics, which of course can be studied by analyzing instrument readings from radio telescopes and other devices that don't necessarily have visual outputs. My wife is his piano teacher, and she has had to adapt her teaching to her first student who cannot read a printed musical score.

A much younger person I know who has very limited vision (and the prospect of declining vision as she grows up) attends summer mathematics programs with children running around playing soccer and Frisbee and seems to handle that with aplomb. To not even be able to recognize shapes or moving human beings, something that the blind people I know best are still able to do, would be especially challenging.

Aside: Have you all noticed that people who have acquired profound deafness that begins in adulthood have much less understandable speech than people with normal hearing? Apparently we all rely on feedback from our own senses to keep our speech behavior within the phonologically normal range of whatever language we speak as a native language, and habit alone can't maintain the fine tolerances necessary for readily understandable speech.

AFTER EDIT: Of course anyone can experience total lack of sight simply by going into a totally unlighted place. The human eye doesn't emit vision rays, after all (even though the ancient Greeks seemed to think otherwise), so if you are where there is no light, you see nothing with your eyes.[2] Studies on the human diurnal behavior cycle are sometimes done in deep caves with no source of artificial light.

[1] http://legge.psych.umn.edu/

[2] http://www.spring.org.uk/2008/03/50-of-college-students-thin...


In regards to your aside, I essentially went through the opposite situation, i.e. I gradually lost my hearing as a kid (genetic condition) until I was completely deaf, and then got a bunch of surgeries which fixed the situation (until I lose everything again in about 15 years, or so I'm told).

In any case, my speech was affected in the way you describe. Most soft sounds started merging, e.g. 's', 'sh', 'tsh', etc. would all end up sounding like 'sh' coming from my mouth, and I had absolutely no idea that was the case. Similarly, I had no idea what the volume of my voice was, it'd either be really loud or really quiet, but rarely at the right level. My parents (mostly) told me I wasn't speaking properly (it took years before anybody realized I was going deaf, including myself), I ended up relying heavily on the vibrations I felt in and around my mouth/throat to correct these as much as possible.

Interesting aside to this aside, there exist implants for people who were born without a cochlea (the spiraly thing which "translates" vibrations). These implants are made of some alloy (not sure what exactly) which thankfully emulate a cochlea, but have the interesting side-effect of causing the affected people to speak with a fairly monotone and somewhat metallic voice.

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.

The Americans I knew when I lived overseas for three years (on each of two stays that long) definitely had trouble with vocabulary retrieval, the more trouble the longer they had been away from native speakers of English. Correspondingly, Chinese people I know who have been away from places with lots of Chinese printed text often have a lot of trouble writing Chinese characters that everyone learns in school. Even "overlearned" skills that become second nature can degrade through lack of continued practice.

Similarly, I've spent a lot of time in the US lately and people can no longer really place my accent. It sounds neither native to here, nor what people from back home have.

Quite odd.

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.

Herzog's Land of Silence and Darkness [0], which follows some elderly members of the German deaf-blind community, is one of the most fascinating documentaries I've ever seen. One quote in particular has stuck with me since I saw it years ago:

“People think that deafness means silence, but they are wrong. It is a constant noise that ranges from a gentle whisper going through some cracks to a constant buzz, which is worse.”

[0]: http://en.wikipedia.org/wiki/Land_of_Silence_and_Darkness

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!

Strange that the article doesn't mention the blind spot that everyone as.


I learned about the blind spot in my Visual Analytics course during my Masters. I wasn't aware of this phenomenon prior to that and it was fascinating to take the blind spot test and to learn that the brain interpolates vision for the blind spots using data from the surroundings, memory etc. so well that we never notice the blind spot.

I wonder if such a phenomenon occurs with people who lost sight during their life and aren't blind by birth, where the brain fills in the blanks based on memory.

On the blind spot test, cover the other letter with your fingertip for same effect, and watch your finger disappear. For some reason this is far more impressive to me.

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.

Having tested it, it seems to do a linear interpolation from the edges, often retaining the surrounding texture. Kinda like the smart fill from Photoshop

I have exotropia on one eye and completely lack binocular vision.

My right eye is my "main" eye (95%) and my left eye just submits the missing parts from the left that my right can't see because of the nose being in-between.

I always have the right side of my nose in my field of view, except that at the same time it's somehow not there. Like 50% opacity. The left side of my nose isn't visible.

When I "hide" a finger behind my nose for the right eye and look in it's direction it's gone. When I stare straight forward, it appears again.

(My) vision is weird :).

Katawa Shoujo actually addresses this in-game. One of the game's characters, a blind woman, describes her dreams including sensations from her other senses: smell, taste, touch, hearing. As something I have wondered about, I was really pleased that the game's authors thought of this.

A blind person once explained it to me:

> I see what sighted people describe as "white". When I ask a sighted person what they see out of their elbow they typically get it. They see "nothing", but if pressed will usually say "static" or "white".

I suspect you experience true blindness (briefly) during laser eye surgery, when the flap is cut in the cornea. I remember how odd it felt - the feeling of seeing nothing at all, not even darkness.

Here's a reference, you downvoting HN twits:


"you have to pump the pressure up in the eye to about 6x normal in order to cut a good flap, as you can't cut an accurate flap in a floppy eye. The pressure is actually higher than your blood pressure, so the eye stops perfusing with blood, and you go temporarily blind."

I could see after the flap was lifted. This was 2005 so I don't know the procedure anymore, but I was supposed to keep my eye trained on a flashing dot while the laser ablated my cornea.

I meant when the blade goes into the eye. There were a few seconds after that before vision came back.

Tommy Edison, the Blind Film Critic's take: https://www.youtube.com/watch?v=ZDHJRCtv0WY

They see what you see out of your elbow.

Many years ago, blind people might put their hands on your face to help them get a sense of you. A blind friend of mine, Jim, got in the car with us, one night, and sat next to a friend he did not know. He put his hands on the other guy's face, then paused, then said, "Man, you are uuuuuugly!".

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