Motion parallax (March - October, 2012)

So, I started therapy with Dr. Richard Kavner. I kept coming for sessions two or even three times a week, though later I reduced it to once a week for financial reasons. When given exercises, I diligently did them at home, but with considerably less enthusiasm than I did during my own experiments. This, by the way, was a huge mistake. I notice over and over how essential can be quantity.

Even though it looked like there was a little bit of improvement, gradually I lost even more enthusiasm. The first 20-30 sessions passed, I decided to continue therapy, and there was no end in sight. My vision was O.K.; however, now, I was "blessed" with double vision, which became a very pronounced issue after an initial period of VT. My right eye was more thoroughly unsuppressed and was actively fighting with my left eye. At the same time, perceptually everything was about the same. It looked like we were just doing a little bit of "polishing"; fundamentally, the "3D" was the same as before.

Whenever I did exercises with various stereograms "hanging in space", I would often receive instructions to sway my body left and right and to see, if the imaginary stereogram were moving "the same direction" or "the opposite direction". I did my best, although this always seemed to me a stupid exercises, as "obviously", if you sway right, everything would move to the left, and vice versa. Gradually, though, I became better at doing those exercises, and recognized, that sometimes the image would move "in the same direction", and sometimes --- "in the opposite".

Then one day, probably in September-October, 2012, I was walking down the street in Brooklyn. There were cars parked along both sides of the street. I was walking and, as usual, looking at the street, the cars, the trees, notice the depth, the distances, and so forth. Now, since I was walking, so to say, forward, the cars were perceptually moving back for me, much like if you look out of a train window, everything will be moving back relative to you. At some point I looked at a car parked on my side of the road, and noticed in the periphery, that the cars on the opposite side were moving forward. They were moving in the wrong direction!

This made no sense. The cars on the opposite side of the road seemed to be moving forward when I was going forward, so long as I looked on the cars parked on my side of the road. However, if I looked further away, perhaps at the buildings on the other side, then all cars seemed to be moving backward, relative to my movement. That is, it mattered where I was looking.

This was an entirely new phenomenon. Prior to that, the direction of my gaze had never made much difference. Of course, if I turned my head or my body, I could look at other things. However, it my no difference, which particular object I was looking at; it was much like moving a mouse pointer on a computer screen: "visual focus" simply meant "attention". Yet in this situation, shifting my gaze while moving changed the direction in which the cars (that I saw in the peripheral vision) were "moving": from backward to forward. It really mattered, what I was looking it; and, in fact, I received immediate feedback as to what I was looking it. Of course, at first it was not easy to trigger this parallax effect: it had to keep looking at a particular car or object for 5-10 seconds before the effect kicked in. But I immediately went for a walk, and after 1-2 hours I was able to reduce the time to less than a second. That is, if I started looking at some object while walking, after about 1 second I felt that the parallax effect started working somewhere in my visual system, and lots of objects in the periphery suddenly started moving, one way or another. On the following days this parallax effect only got stronger; and it has been with me ever since. Now I can hardly imagine, what I "saw" prior to that. The best explanation I have is that prior to discovering this new "parallax effect" I had never been looking at anything, or at least not consistently. True, I had written in this blog about "binocular focus", but I think that I had been very imprecise with my focus, sometimes looking a little in front of an object, sometimes a little behind, and easily loosing focus when either I or the object was moving.

Of all the changes that I have so far experienced in vision therapy, that was perhaps the most significant one. It was almost as surprising as the original discovery of stereopsis. Almost all of the other changes during my vision therapy have been relatively minor, incremental; this one was radical, black-and-white kind of change, after which the new mode of seeing quickly and completely replaced the old one.

If I take off the contact lens on my eye, the fusion get much worse, and the parallax effect does not work that well. But this is still not the same as it was in the past. Now the parallax effect makes complete sense. I could even draw a diagram. Of course, if I am walking along the street and looking on the car on this side, perceptually the cars and the buildings on the other side would be moving in the same direction. Yet a little more than a year ago this was virtually beyond my imagination.

Update: October, 2011 - March, 2012

Many people have asked me to continue my blog, so here is an update.

After the events described in this blog I stopped regular work on my eyes, as I didn't have the enthusiasm to devote to it several hours every day without any clear direction. Gradually my vision deteriorated a little bit. The stereopsis stayed, but it became somewhat weirder, somewhat more unfocused. I went for an evaluation at New York Eye and Ear. First of all, they prescribed me contact lenses as my right eye was a bit nearsighted. They gave me -1.75 for the right eye and also temporarily 0.50 for the left, normal, eye, just to help to recover the balance between the eyes. After a few weeks they still checked my vision and concluded that my right eye was "beyond training" and that I needed an operation for strabismus to recover. They also checked for fusion with a prism, to straighten the right eye, and -- indeed -- I was able to see a stereogram in this case. So they concluded that the strabismus operation was likely to be effective. I asked about the risks. The doctor (Christopher Seebruck, MD) said that the risk was comparable to that of being hit by a lightning; though, on the Internet I found out that even the chance of death from a strabismus operation was rather high, much higher than that of being hit by a lightning. But, anyway, in February, 2012, the congress of doctors told me that I needed an operation, and that I should make an appointment if/when I made this choice. For some reason they really stressed that I had some "pseudostrabismus", so that even after an operation, my eyes wouldn't be cosmetically 100% straight. This didn't really bother me that much; I was more worried that an operation could cause some irreparable damage; and, besides, after my own experiences of discovering stereopsis, I couldn't believe that my right eye was "beyond" training: after all, I saw 3D around me, and they tried to judge it by some tiny stereogram that, probably, required much higher stereoacuity. By the way, the doctors were not terribly interested in my story about acquiring binocular vision. Only one very old and experienced doctor, who at one point came to check my eyes, seemed to attach some credibility to my explanation. Also, they discussed it all with me on a very basic level: eye in the center, eye on the side, etc. At times I felt I knew more about stereopsis than they did.

In the meantime, I made an appointment with Dr. Kavner, a vision therapist recommended to me by somebody from Peter Grunwald's retreat. He made an initial evaluation and said that he should be able to make my eyes to converge at a relatively close distance --- I forgot, perhaps a foot --- after 20-30 sessions, if I remember correctly. He was not that interested in my own story either, but I didn't try to push it after the way it was received at NYEE. After that visit I didn't really have an opinion, but I did notice that my vision somewhat improved just after this 30-minute evaluation; and I wondered, how beneficial should be the actual therapy.

During the winter of 2011-2012 I went home to Russia and decided to get a third opinion. I went to "Eksimer", a top, fancy, dedicated vision clinic in St. Petersburg, and paid for a complete evaluation.  I was evaluated by two doctors: one --- a very experienced opthalmologist with decades of experience; the other --- specifically an expert on strabismus. Now, recall that, in addition to strabismus, I had imperfect vision in my right eye: a lens for -1.75. The first thing they told me: I needed laser correction. That was the first step, and then they had to make the decision about strabismus operation. I mentioned the opinion I received in New York --- one by NYEE, the other by Dr. Kavner. Both opinions were dismissed; they said something like "We here [in St. Petersburg, Russia] know what we are doing; they don't know very much [there, in New York]". But wait... On top of that they offered me a 10% discount on laser correction if I did it TOMORROW. This was not an easy decision to make, but eventually I convinced myself to decline this option, as clearly they didn't have my best interest in mind. Furthermore, my mother argued that, should I have any issues, I'd have to travel back to Russia to see a doctor.

Back in New York, I still had to decided what to do. Eventually I decided to give vision therapy a try --- after all, I was promised some specific results after 20-30 sessions --- and, thus, not to risk going for an operation right away. I was also very curious about VT, and it was much more in line with my philosophy. Though, I admit, it was tempting to just go and schedule an operation, so that --- it seemed --- all my problems would go away in just a few weeks.

So I started vision therapy with Dr. Richard Kavner. This was in spring, 2012...

Visual experiences of 3d: the Museum of Modern Art

In the museum I've got an interesting new feeling that it is a space full of people that came to see art. I already wrote about this phenomenon. Before it was about me going to a museum and seeing art that's over there. Now it is a place full of people, and I am one of them, wandering around in between pieces of art.

Let me write about good things. First of all, Kandinsky. I am not sure if I have seen this painting today at MoMA, but you get the idea, what kind of paintings by Kandinsky I am talking about.

If we take it for granted that Kandinsky had synesthesia, then it's so simple. No more worries trying to understand his pictures. You know how people look at his pictures trying to figure out what he meant? Picking up lines, circles, splashes. That's how I had been looking at the "Magic Eye" pictures, trying to discover something in the patterns, hoping that it will suddenly show me that hidden picture. I still cannot see them, by the way, but now I can look through, and at least I see that it is possible to see something else, not just whatever is printed on the page.

I can try to understand synesthesia through my understanding of stereopsis. Just like it is virtually impossible to imagine stereopsis unless and until you have it, it should be virtually impossible to imagine synesthesia unless and until you have it. That is, you may be thinking for hours about how sounds can be colored, and not get anywhere. However, I can relate to it by interpreting stereopsis as synesthesia. Then I can project it further and get at least some sense of what seeing sounds or hearing colors may be like. Furthermore, there is the natural smell-taste synesthesia that virtually everyone has but hardly anyone recognizes as synesthesia. In summary, if you want to understand Kandinsky, relax and look at the painting non-habitually.

I also noticed, as I looked at his paintings longer and longer, trying to connect to various parts of the visual system, how sometimes the whole room got darker. At this point the picture would sometimes disassociate into two or three layers, that is, each contour would belong to one of the layers, and sometimes one of the layers would be shifting with respect to the others. The layers were not separated in space, though. Also, at the same time as it got darker, all colors would disappear, and the picture would become brown-grey instead of red-yellow-blue-green-and-who-knows-what-else.


Then, Claude Monet. Look at the lilies. Those are not the ones that are at MoMA, just whatever is easy to find in the Internet.

I don't think I had ever realized that all those paintings showed the surface of the water at an angle. You just have to take my word for that... I had surely realized those were lilies on water. But you can actually see that there is an angle. You can see what angle the surface of the pond makes with the surface of the picture. This is new.

In fact, now as I looked at a huge painting with those lilies, I could easily see how the pond continued outside, from out the picture. I am not sure normal people can do that. I guess, a normal person would need to close one eye in order to suppress the feeling that the canvas is flat and to see the volume. I would assume that Monet himself was able to see volume with both eyes open. I can certainly switch back and forth with both eyes open: to see just the picture or to allow the water to continue out into the space of the gallery, with the lilies.

I tried the same with Picasso - it didn't work quite well, but it seems possible. That is, instead of just conceptualizing, what a cubist painting may be about, one can simply see the space in it as it is, albeit different from our space. I recently had to exercise my ability to see distorted space when I noticed my reflection in the faucet in my bathroom with one eye deviating to the side. As I looked in the regular mirror, however, the eyes were fairly well aligned. I guess, fusing two curved images was still a little bit too much for my brain. However, I was able to improve it, to a degree, by looking into the reflection in the faucet and seeing there the space in the bathroom, but curved. The same technique can be applied to Picasso: look at the painting, perhaps with one eye only, and see the curved space inside it. Not sure if it has to do with the observation that Les Demoiselles d'Avignon actually have strabismus, at least the three of them whose eyes we can clearly see. Of course, their eyes are not the only thing in the painting that can remind me about strabismus: with a moderate stretch of imagination, the whole picture may be seen as the result of switching between the views from two eyes.

After the museum I went to have dinner in a place called Lindy's on 7th avenue. Just a warning if you decide to go there: read the menu and the prices before ordering. The pricing is counterintuitive. I had a great dinner there and paid about $35 including a very generous tip, but once again, the prices are totally random, so you have to choose wisely. One interesting experience with binocular vision was when I went to the bathroom... On my way back I looked at the landscape of the cafe and felt a little bit lost, because the landscape didn't look like anything familiar. However, then I recognized that it didn't look like anything familiar because I was at a different angle, and I still used my old and ineffective navigation habits. Instead, I looked at the structure of what I see, realized what was where, and as I turned to the right, the environment rotated, showing me the familiar picture with my table, just what I was waiting for.

As another interesting experience, after I had my dinner I was thinking what I wanted to drink or if I wanted a desert. I took some time because of the random prices - I spent several minutes reading it over and over. I noticed the waiter in my peripheral vision and thought he was going to ask me if I had finally made some decision. At this time I was drinking water from a glass, so I automatically stopped drinking and barely started moving the glass from my face. Almost simultaneously I noticed that I noticed - that is, I became aware of my very reaction, and started deciding if I wanted to inhibit it, to go back to drinking, put the glass on the table, or something else. Of course, all that took only a split second. Yet at almost the same time the waiter slightly shifted his direction so, as I recognized in my peripheral vision, he was now moving a little more away from me, and said something like "Don't worry. Please, take your time." - and left.

This impressed me so much. This guy noticed my reaction so early that by the time I started inhibiting it or otherwise deciding what to do with it, the glass still an inch or two from my mouth, he had already changed the trajectory of his walk, and was ready to start saying something to me. It was probably an automatic response on his part. In other words, the only possible explanation is that he did what he did subconsciously, as a result of his experience, after having served to many different people and learning to pick up all kinds of signals. Anyway, that's why I left him a tip in excess of 20%.  Good job.

Suppressing stereopsis

I decided to try to suppress stereopsis to see if I am still able to push everything on a flat screen.

I started trying outside, on the street. The method I used is the following: I tried to conscious reinterpret whatever I was seeing as a flat picture. I tried looking with one eye and looking with both eyes. I found it particularly useful to look at the road, thinking that as the road moved away from me, it was going up. I was also trying to see people coming towards me as going down and growing, increasing in their size. I was trying to see people going away from me as going up and decreasing in their size. In addition, I was trying to soften the outlines of the objects to see people and other objects as pasted on top of the background.

Sometimes the illusion was starting to work, but then something happened, and I went back to stereopsis. I found the following triggers:

Moving person. If there was a person walking close enough to me, then it almost inevitably triggered stereopsis. It was easier to see the person two-dimensionally if he or she was moving either towards me, or away from me, or perpendicularly (the easiest). Even then I had to remind myself that I was seeing a flat picture pasted on a flat screen and to constantly inhibit any 3D interpretation. If the person was moving diagonally, and fairly close to me, I basically had to look away, because I couldn't push such a person onto a flat screen.

Trees. I was somewhat able to view trees as flat. However, as soon as I looked up on the interweaving branches and the complex patterns of the leaves, the stereopsis became very strong, and there was virtually no way of suppressing it. It was like looking at something red and saying to myself "It is blue! It is blue!" in the face of evidence to the contrary.

Sharp outlines. This is a very strong reflex. I would start to feel I was going back to a flat way of looking at least in some respects, then I would suddenly see a plant, a person, or anything else, with a very sharp, clear outline, and the sharpness of the outline will collide with the flatness I was trying to look at face to face. The stereopsis gets restored suddenly, and I feel as if a bubble suddenly appeared in my brain and was rising to the surface. In order to keep some flatness it is necessary to soften the outline and to repeat to myself that this is just a flat picture, not a 3D object, but this still does not quite work. Basically, I had to look away from all sharp outlines if I were to get at least some flat effect.

Shadows. This reflex is also quite strong. If I see a shadow that is a particularly good cue for volume, that is, its relation to the object casting the shadow highlights the three-dimensionality of the object and its location in space, it is again very difficult to see a flat picture. It is not enough to ignore the shadow. I have to imagine that the shadow goes at a wrong angle in order to keep some flatness. I have to constantly keep reminding myself that the shadow is slanted and to constantly inhibit the 3D interpretation of the shadow.

Perspective. This is perhaps the strongest reflex. A few times I felt like I was starting to see a flat screen again, that is, my previous reflexes were starting to work. Then I would suddenly notice that I was seeing a path going away from me, or an arch enclosing the entrance to some building. This would elicit a strong sense of perspective immediately restoring the stereopsis. It is very difficult to suppress the stereoscopic interpretation of perspective. I have to constantly remind myself that the verticals I am seeing are not verticals, but slanted lines.

Overall, when there were many of those triggers, it was virtually impossible to maintain any kind of flatness. It was much easier if I turned away from most such objects and tried to only look at things that were not strong stereoscopic triggers. It was easier to see flatness if I was not moving and if other things were not moving either, at least not very close to me. I found many more stereoscopic triggers outside than inside. Now I am in a cafe with Internet writing down these notes. Here there are not so many triggers so it is easier to suppress stereopsis. In fact, here it is even difficult to say whether stereopsis is active or not, since for this environment it doesn't make that much difference. The organization of space in this cafe really encourages seeing everything as a big mess of pictures pasted on top of each other. Also, the coloring scheme used in this cafe allows me to see the floor and the walls as continuations of each other, which also makes it easier to suppress stereopsis.

I conclude that it is better to work on developing stereopsis outside.

Another conclusion is that it is virtually impossible or at least very difficult for a normal person to experience flat vision, given that it is already so difficult for me. There are so many triggers of a stereoscopic worldview, and most of those triggers have to be inhibited in order to gain a different perspective. If you are interested, I suggest you start from a painting or a photograph. Look at it with one eye and try to alternate between the flat interpretation and the 3D interpretation. When I say "alternate", I mean "consciously switch back and forth between two interpretations", just like you can do with this picture:

You can see how looking at one or the other mouth or nose triggers one or the other interpretation. In much the same way certain objects, shades, or outlines can trigger 3D or 2D interpretation of the whole scene.

This reminds me of my work with a speech therapist a little less than a year ago. I was working to improve my English pronunciation, since even though I was and am completely fluent, I had gotten tired of the imperfections of my speech.

When people live abroad and use a foreign language in their daily activities, they usually pick up more and more words, so their vocabulary grows, their understanding of the subtleties of the meaning of the words and of the grammar gets refined. However, for many people their pronunciation does not get better. A lot of Russians, for example, live in the United States for decades, and still pronounce words in the same way. They will say "bus" with the same vowel sound as in "father", over, and over, and over again. In fact, many Russians will not even hear the difference if you ask them to pay attention and compare the vowel sounds, and then pronounce "bus" and "father" very clearly. So strong are the habits of the mother tongue.

Similarly, a lot of Russians will pronounce the word "very" with a sound [w], even though [v] is almost identical to its Russian counterpart, while [w] is quite unusual. There is something in the way people learn and conceptualize Russian and in the way Russian native speakers learn and conceptualize English that makes many Russian native speakers incorrectly deduce that "very" should be pronounced as "wery". Again, it is difficult to hear the difference, because once you have a framework in your conscious or subconscious mind, you hear what you expect to hear.

As I was working with my speech therapist, I was recognizing more and more of my linguistic habits. It was not so much about being able to say a particular sound, more about simply hearing the sounds of the English language as they were. I recall one particularly successful session when I felt I made a lot of progress. At some point my teacher was saying some words or simple sentences, and I was repeating them. If it was not good enough, he would say again, otherwise he would move on to some other word or sentence. I remember how things started to really work when I was able to stop listening to the language and start listening to the sounds. I disengaged from the meaning and was just reproducing the phonetic patterns that I was hearing. As
I was able to let go of the meaning more and more, I stopped recognizing the words, and the process became easier and easier. A few times my teacher was very satisfied with how I repeated some word or sentence, and then I asked him to explain, what was the word or the words that I was repeating. In most cases words were very simple, yet I couldn't get them. When after a few repetitions I would understand the word, I was often surprized that this word or expression can also be heard or pronounced in this new way. It was probably essential that I did not have written words in front of me, for my habitual way of saying and hearing was strongly connected with how a word is written. I subconsciously applied some of the principles of Russian language and it made me hear and say English words in a typically Russian way. For example, when seeing the written word "letter", I would naturally try to pronounce the sound [t] twice. Similarly, I would make a longer sound [s] when saying "massive" than is necessary. When saying "baby", I would hear and pronounce the second vowel sound as [ə], the second vowel second in "after" or "matter", instead of pronouncing it like the vowel sound in "tree".

Why relaxation changes habits

 In Alexander Technique people often talk about habitual tension and how you can release the tension in your neck, in your shoulders, in your back, and learn to do the ordinary things or whatever it is that you do every day without this tension. Dr. Bates, the creator of the Bates method, was also writing how most difficulties with vision come from excess tension, and we can only relax the eyes, our vision will, in many cases, become very good. This makes sense for myopia if we assume that the eyeball is elongated because of the excess tension in extrinsic eye muscles. Similar explanations can be constructed to explain why double vision, or lack of binocular vision, or poor night vision also come from excess tension. However, there is something unsatisfactory about this explanation.

It seems that "excess tension" often denotes "poor use", where the word "use" is to be understood in the context of Alexander Technique. "Tension" just refers to an effort, conscious or subconscious, to interfere with the natural course of things to gain some end. In many cases what is called "tension" is really an adaptation.

I've been recently thinking about breathing and relaxation and, particularly, why is it that when I take a lunchtime yoga class in a fitness club at work, it is as I noticed more difficult to breathe freely during that class, than when I take a yoga class at some other time, perhaps during a weekend. Even though the fitness club in question is underground, I thought that perhaps I picked up some tension from other people at work, or even tensed myself, and so it affected my breathing.

On another occasion I was looking myself in the mirror while at work and noticed with disappointment that one of my eyes again turned away. Then I somehow recalled what I had been thinking about breathing, and started to breath deeply, trying to slow down and relax. To my amazement, the eye started turning back to the aligned position.

I think now I understand it. The eye turns away as an adaptation, when there is a contradiction between the input from both eyes that is difficult to resolve. If the situation is urgent and requires an immediate action, it is essential to provide as accurate visual input as possible, thus the eye turns away. However, if I am more relaxed as there is no immediate threat, the need for adaptation will be less, and the eyes may be able to work together, and this ability will develop further and further.  A change of habit, and learning in general, is only possible when the situation is not critical for survival, and imperfect functioning is acceptable. Relaxation allows for the habits to change and for learning in general because it decreases the need for adaptations.


Every time you are learning to do things in a new way, there will be a transitional period during which the old way will be more efficient than the new way. For example, you have used a certain computer program as your text editor for years, and now you are switching to a new one. The new one may be better in every imaginable way, but since it is different, you will have to struggle for some time until you eventually become as productive and later even more productive than you were with the old program. The transitional period will be shorter if you make the change instantly and fully commit to using the new program. However, if you keep using the old program when you need to do something quickly, because you really need it, you may never complete the switch. Furthermore, you will be much more successful with the new program if you embrace the philosophy of the new program as if you have never seen a text editor before. Most people, however, will start learning the new program by finding ways to do things that they often did in the old program.

People who develop and sell computer software, as well as engineers in general, have to acknowledge this human tendency, if they want their products to sell. If they come up with something radically new, it will either result in complete success as was the case with Apple iPod, or in complete failure, as happens with most other projects.

Why is it that people are frustrated when a program takes forever to load? Why is it that people are annoyed when they install a new program and all buttons are in different places, and they cannot find anything in the menu? Most people use computers because they want to accomplish something: write a poem, edit a picture in Photoshop, check train schedule in the internet. They are preoccupied with action out of doing, rather than out of being, and their way of acting will be necessarily habitual. They will keep doing things for years the same old way, because it works. You know how people say that they are bad at computers because they cannot accomplish XYZ. The most successful computer users are young kids who are using their computer without any intent to accomplish something, it is just their way of being.

When a computer user is trying to accomplish something, the immediate need or desire to finish the task prevents him from seeing other possibilities. Learning is prevented by the need to accomplish. If you want to learn, you have to be fine with failing, even if you know you can succeed the old way. Now, if we are talking about a survival scenario such as a war, then it may be inappropriate to learn to shoot in a new way and better to rely on the established skills of shooting in the face of an immediate danger. A computer user may also have a survival situation if he is, for example, a flight dispatcher. Then he will naturally use his established skills to deal best with his immediate environment, sacrificing any chance for learning. Similarly, if you are undergoing vision therapy, but your environment strongly requires you to see as clearly as possible, you will probably rely on your established visual skills, and there may be little progress. Evaluate every task, situation, and environment that you encounter. Either classify it as critical and use your best abilities as of now, or classify it as non-critical, relax, stay present, and allow for learning. Choose wisely: sometimes it may be better to sacrifice learning.


If you are interested in the subject of software and frustrated users,  read this blog post by Joel Spolsky: Controlling your environment makes you happy This post is included in his excellent book "User Interface Design for Programmers". Even if you are not a programmer but merely an active computer user, you may enjoy reading this book. For example, this is one thing that I learned from that book. If you are using Windows, you are probably familiar with the Recycle Bin. In Windows 95 when there was something in the Recycle Bin, it looked messy. Even though it was meant to allow people to recover the files that they accidentally deleted, research has shown that most people emptied it on a regular basis, because they wanted their computer desktop to look neat and organized.


Coming back to the original discussion: this is the other side of the coin. Not forcing people to change their habits too much or to learn too much when they are trying to accomplish something allows them to relax a little bit. Then, once they relax, a little bit of learning may be possible. This is why, when you teach, say, how to dance salsa to somebody who has never danced before, it is essential to first create a comfortable and supportive environment so learning can take place, for otherwise they will focus very hard on looking their best in this embarrassing situation, and no learning will take place. Clearly, during the transitional period they will have to look like they don't know that they are doing, and people like to feel in control. On the other hand, if you are that person who is trying to learn some salsa, understand that this is probably not a survival situation, and without reframing it, simply let go of the need to be in control.

Visual experiences of 3d: modern dance class

These are my observations after today's modern dance class (Hawkins technique).

Overall, for watching modern dance it makes more difference whether you have stereopsis or not, as opposed to whether you have ballet. In other words, if you have never had stereopsis, you are not missing as much when watching ballet, as you are missing when watching modern dance. You are still missing a lot in both cases, as well as in case of theatre. There is even more difference with architecture and especially sculpture.

Two weeks ago, when my stereopsis was just making its first steps, I had a lot of difficulties in this spacious studio on Lexington Avenue. The studio has some style: it has large pictures on at least two walls, it has chandeliers, it has various other decorations on the walls and the ceiling. However, I recall how difficult it was for my stereovision there, particularly in relative darkness, since there were not many objects to see in 3d to support my stereovision, and the room fitted quite well into the 2d view.

This time it was much better. If you studied mathematics for a long time, you may have heard that there was a certain shift of perspective that took place in the XX-th century. Previously mathematicians focused on studying the properties of various objects: points, numbers, groups, fields, manifolds. Then the focus shifted to studying the transformations of various objects: functions, operators, morphisms. The properties of functions became more important than the objects themselves, since once you know all the ways how a certain space of points or objects can be transformed, it gives you a great deal of insight into what may be considered interesting or essentials properties of this space, while leaving out the uninteresting or accidental properties. (Of course, no such formal distinction can be made, since any function or operator is also a point in the appropriate functional space, and conversely every point or object x is a function on the space of all functions whose domain includes this point, via the natural duality x(f) = f(x). )

Quite similarly, every day I am seeing all those various objects. Sometimes some of those objects can be useful or, indeed, necessary for my survivial. Yet the vast majority of the objects that I am seeing are not important for me in themselves. Various objects come together to form one visual impression, in which every particular objects may be of little importance. However, as I am walking or simply moving my head, I see how my vision of all objects is transformed. The objects move in the direction opposite to the shift of the gaze and, because of the motion parallax, objects that are closer to me shift more in my visual field than those objects that are farther away from me. This shift of all the objects that I am seeing, this transformation of the objects in my visual field, gives me the feeling of being and moving in the space.

When I first acquired stereopsis, my attention was mostly focused on the three-dimensionality of individual objects, such as a tree with its leaves, an animal, or a person. When there were few objects with obvious three-dimensional features, such as in the studio on Lexington Avenue, it was difficult to maintain binocular vision, or when it was already established, was difficult to maintain good quality, strong binocular vision, because binocular vision was not really required. It hardly made any difference. However, now that I understand and feel, how movement is an essential part of binocular vision and of the experience of stereopsis, particularly after my time on a ship and later on the ferries to and from the Governor's island, I can sense volume even in an empty room if only I can notice how the room flows relative to my movement or to the movement of my head. This is, of course, not something that happens automatically, but rather I have to remind myself to notice this optic flow of the environment, as well as the motion parallax, and the more I am noticing it, the easier and smoother it becomes.

I already wrote about it in an earlier post: watching the optic flow is tremendously helpful for dance if you want, for example, to move your legs but to keep your head in one place in space. Then you simply see what you see and make sure that whatever you see is fixed, that there is no movement of the objects that you see in any direction, which would mean that your head is also fixed in space. Of course, once you feel it in the body, you can probably do whatever such movement you are trying to do with your eyes closed, but the technique I described should allow to learn the movement much faster than by other means. This is in agreement with my philosophy that stereopsis is a learning tool, and for humans this confers more advantages than any real-time aspects for catching the ball, with the possible exception for driving, flying a plane or a helicopter.

However, even when the movement is already in your body, binocular vision, more specifically the movement aspect of stereopsis - optic flow with the motion parallax, provides very valuable real-time input. This input can be used for better technique even as you are performing and not thinking about the technique. For example, yesterday I noticed that when you relevé, that is, when you lift your heels off the floor, the ceiling comes closer to you, even if it is very far. Yesterday was he first time in my life when I noticed it. How had I seen it prior to yesterday? Prior to yesterday I had certainly recognized the change in the visual field that happens when you life your heels off the floor and go on half-point, and then come back down. However, I had not interpreted this change as the ceiling coming closer to me or moving away from me. Since I lacked such a natural and obvious interpretation, the changes appeared mostly random. Of course, when something appears random and you cannot conceptualize what you see, then you can not notice anything. Imagine someone showing you a computer sceen with many patches of random colors, generated entirely at random, without any visible pattern. Do you notice anything? Will you able to recall anything of what you see? Probably, not. Of course, you can consciously look at the points in the four corners of the monitor, and memorize their color in the hope that you will later relate it to the big picture, and I had often tried to "notice" things in this way, but this approach takes a lot of work, and the chance of success is small. This was pretty much how I was learning to drive: I was looking at what seemed like a random picture, not very correlated with what I was doing with the steering wheel or with other control, and I was trying to find such patterns, such as where on the windshield glass should I see a car on my left to make sure I pass it safely withe enough distance between us, or where on my windshield glass should I see the sidewalk to make sure that I am ready to stop and my distance to it is adequate. In this context "where" means "how many inches from the rightmost end of the windshield glass", and make no mistake, I really learned to use such cues.

Going back to the topic of dance, I found the optic flow and the motion parallax very useful for turning. Even though people say that you need to spot to not get dizzy, in a sense, you first need to be able to turn and get dizzy in a certain way, that is, get dizzy because you see how things are moving around you in a circle, with motion parallax. That is, spotting only makes sense after you engage with the environment in a certain way. Figure skaters, for example, do not spot, but they see the environment as they are turning, and they decide when they will exit and where the will move after the turn.

To be fair, I am not quite sure if the optic flow and the motion parallax are intrinsically helpful for turning, or if this merely engages the visual system, which in turn coordinates the whole body. Similarly, when I was writing my older post titled "up, down, and other directions", I was not sure if it was the actual stereovision that was giving me the direct feelings of up and down, perhaps via a greater sensory integration with the vestibular system, or if it was simply a matter of bringing both sides of the visual system and both sides of the brain into agreement or harmony, which then allowed me to do all kinds of things.


However, from an emotional point of view, seeing the optic flow of the environment and the motion parallax are important, since they give a feeling of being in the space, a feeling of being in the world, a feeling of engagement. This is, therefore, as important for dance as for anything else, theatre, public speaking, cooking, you name it.

I am abandoned in the world ... in the sense that I find myself suddenly alone and without help, engaged in a world for which I bear the whole responsibility without being able, whatever I do, to tear myself away from this responsibility for an instant.

Jean-Paul Sartre

I do not think that this being or not being in the world is only a function of binocular vision. This is probably more a function of being present. If, for example, you have never danced, or sang in public, or played table tennis, and then you decide to try, you may feel awkward, very uncomfortable, embarrassed. You will feel detached from your body, you will almost not want to be responsible for your body at that moment. In some subtle sense this feeling is similar to the experience of not having stereopsis: you are hear, and everything else is over there, in this picture. Conversely, if you can invert this feeling to its opposite, to the feeling of being engaged, then this is what stereopsis can give you, a feeling of being in the world. 

I guess that even people with normal vision have stronger stereoacuity, color perception, sound perception, when they are present and engaged with the environment. This is because when we are not present, when we want to hide, to be somewhere else, we are actively intending to be out-of-the-world, and this may result in suppressing some depth perception, some color perception, or even closing one's eyes. 

Next time when you feel like you want to be somewhere else, whether it is a difficult dance class, an unpleasant conversation with your manager, sorting things out in your relationship, an argument with a police officer, think about what you are doing for yourself. Unless you are being tortured and you know you are going to die in the end of the torture anyway, in which case it is understandable that you want to die underfocused instead of dying with full awareness, including the awareness of suffering, unless this is what is happening to you, think, what is it that you are doing for yourself. You are taking yourself out of an experience. Even if you are not willing to make the choice to live with full awareness and authenticity, think what it is that you are doing for your brain. You are teaching your brain this mode, of not-being-here. You are disconnecting all those nervous circuits that integrate the sensory information and provide you with the feeling of being here and now. This involves vision with depth and color and motion perception, this involves hearing, and all other senses, as well as perceiving body language, perceiving the emotions, and more, and more, and more. If there is no immediate danger, we want to have a better living experience, just as Peter says: thriving, not surviving. 

Lessons from binocular summation

Binocular summation is a very useful feature of binocular vision. With two eyes the threshold for noticing a stimulus is much lower than with one eye. As I walk down the street, I notice birds, flies, mice or insects on the sidewalk. I sense the movement, and I recognize that my threshold for detection is now unusually low. I notice movement, and I notice how subtle it is. I watch dance and I see subtle movements, and I recognize them as subtle; I see that I was not able to notice such subtleties in the past. It may, of course, be that my visual system has been educated, and those skills may still persist with one eye closed - not sure.

What makes a subtle movement stand out is that both eyes receive coherent inputs. I also suspects that every time I notice a subtle movement and the object that is moving is small, such as a dust particle, my eyes have to be sufficiently aligned. Conversely, when the inputs from both eyes are too different as is common because of strabismus, this results in confusion, and a general feeling of discomfort.

Recall that we can interpret binocular vision as a sensory integration of the inputs from both eyes, at least I propose this approach. Here is a quote that triggered my thinking of how we can apply it to other areas:

For example, winking when you talk to someone adds extra weight to your message, as does touching them. However, combining both behaviours has a synergistic effect that makes you stand out. It seems this is a key factor on how to stage presence.

(Source: link )

I suspect this is the reason why it may feel so uncomfortable and unsettling when somebody is saying one thing, but the body language or the eyes say the other. We perceive disagreement between the senses, and the responses are probably the same as with the vision. One possibility is suppression: we are only listening to what the person is saying, with an uneasy.  feeling, but generally ignoring the body language that does not match the words. This is analogous to monovision. Another possibility is ambiocular vision. Both sensory inputs can be perceived and interpreted independently, despite the contradiction. This should be easier for someone whose senses are not very integrated. I guess that people in certain occupations such as work in police or in CIA or another similar organizations can benefit from a certain lack of integration of senses, perhaps even certain autistic traits.

When different senses are in agreement, the effect is similar to binocular summation. The threshold is naturally lower, so if you want to reach people, it is advisable to use multiple senses. If what you say is in agreement with your eyes or with your body language, then you will be relying on the audiovisual integration of your listeners to reach them more effectively. When dance and music are in agreement, the whole is greater than the sum; but if there is disagreement, this results in confusion and partial suppression of what you see or of what you hear, or both. This is why it is easier to clap on the beat of the music by yourself than together with the people who are clapping off beat.

This is why if you eat too much garlic in certain social situations, this can be a problem. The people you are meeting with will have a difficult time integrating their various sensory impressions of your person. Even if they understand that this garlic smell is just an accident and does not characterize you as a person, they will still have to suppress the sense of smell, which will weaken the impression from the other senses. Furthermore, if you do not eat garlic, and leave an overall good impression, they are likely to complete your sensory image by attaching it to an appropriate pleasant smell that they happen to come across after meeting you.