Sunday, August 14, 2011

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. 

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