In simple words you have three components:

Tremor movements are random in nature so the "cancel out"

We need some integration time over which the image is formed and within this time tremor movements already reached a steady average

We do not see the objects, but only detect changes (i.e. contours that are filled in the brain).

All together makes that we detect a fuzzy contour filled in the brain, and as a whole is sent to our look-up table of previous experiences and then we perceive. Perception in a sense is just the association of stimuli responses with our experience database

On the contrary, we do detect moving scenes due to the harmonic movement of the moving target.

So each perceived frame is static, but we see a frame to frame displacement.

I hope it helps, and I appologize in advance for just sketching the process without being rigorous with the details.

Charles, your question is answered in *The Cognitive Brain*, Ch. 4, "Modeling the World, Locating the Self, and Selective Attention: The Retinoid System". For an explanation of how we experience the world around us, see here:

http://people.umass.edu/trehub/thecognitivebrain/chapter4.pdf

Don't forget to look into "predictive coding" (Rao & Ballard, 1999; Friston, 2005). Processing of visual input might be controlled through "predictive states". Imagine 2 snapshots of visual input at a slightly different head position. The correlation between those 2 snapshots is quite high. Thus, the first snapshot has a lot of predictive power over the second one. Arguably, this results in a different processing for the second snapshot, which can be largely predicted and, therefore, may result in a percept which is very similar to the percept of the first snapshot. This may be why the transition from one snapshot to the next, by means of head rotation or eye movements, seems so stable.

There are a number of mechanisms and proposed hypothetical models, but one of the better reviews on the subject is Neuronal Mechanisms of Visual Stability from Vision Research (http://lsr-web.net/Assets/NEIPages/BobWurtz/pdfs/WurtzVisRes2008.pdf). The Royal Society did an entire volume on visual stability two years ago, and there's some good stuff in there; all of the articles are available for free online: http://rstb.royalsocietypublishing.org/content/366/1564.toc

You can demonstrate the basic idea for yourself. Apply a little pressure to the outer corner of one eye (gently!) with a finger, whilst covering the other eye. The world around you moves as you push.

The original demonstration of this effect was rather more gruesome. I recall seeing a cine film of Grindley (I think) from probably the 1950s or 60s grasping the white of his eye in a pair of forceps and moving it. These days it is done by attaching a contact lens that can be grasped.

The idea is that the brain compensates for (or disregards) changes in its sensory input that it has caused. The same effect applies to head movements and body movements such as walking, driving a car.

The paper by Robert Wurtz (2008) in *Vision Research* is an excellent review of work on the problem of how we experience a stable visual world. However, I strongly disagree with his preference for a retinotopic explanation for our seeing a stable world as opposed to the alternative spatiotopic explanation for our seeing a stable world.

Here is what he wrote about this extremely important aspect of our conscious experience:

"Recording neurons in the monkey brain during saccades has provided neuronal evidence for the updating of either retinotopic or spatiotopic maps as the mechanism underlying stable visual perception. In the retinotopic hypothesis, the visual world remains represented in a retinotopic map centered on the fovea. With each saccade, there is a brief transition period in which the map is up- dated by anticipatory activity in the visual field area where the fu- ture receptive field will be located. After the saccade the map is still a retinotopic one. In the spatiotopic hypothesis, there is a spatially based map of the visual world that is updated with each saccade. Or alternatively, in one version of the spatiotopic hypothesis, positions are calculated anew with each new fixation (a calibration hypothesis, Bridgeman et al., 1994). In either case both before and after the saccade the map is in spatial coordinates. In spite of these differences between the retinotopic and spatiotopic hypotheses, there are a few striking similarities in their neuronal requirements. Both require a mechanism for updating a map with each saccade. The mechanisms of the updating might be different for the two types of maps, but both require it. Furthermore, both require vastly increased connections over the simple one to one connection for a retinotopic map. Because both types of map require an updating with each saccade, and this updating can come from any part of a retinotopic map, neurons in both maps must have connections to all parts of the entire retinotopic map. How this could be accom- plished has been specified by several models and hypotheses (Galletti et al., 1995; Quaia et al., 1998; Salinas & Sejnowski, 2001; Trehub, 1991)."

Then he writes:

"I do not think that the current evidence for the two hypotheses is equal but rather that there are two reasons to favor the retinotopic hypothesis. The first is that the neuronal evidence for the contribution of the shifting RFs to updating a retinotopic map has become substantial and coherent. The studies on shifting RFs have established a possible mechanism for shifting the visual sensitivity on the retinotopic map, and the CD required for driving such a shift has been identified. This detailed knowledge in turn allows a test of the relation of the shifts to the perception of visual stability. In contrast, a spatiotopic map, distributed or not, has yet to be identified, the signal that contributes the eye position signal is not established, and a test is not obvious. Second, at a behavioral level, there is growing evidence from experiments on change blindness that there may be no spatial map in the brain, but rather a transient retinotopic map with each new fixation. If there were a spatiotopic map independent of the current retinal image, why are such changes missed? The spatiotopic map should be representing the whole field all of the time. In contrast, if there were a retinotopic map that changes with each saccade, such omissions are readily understandable. In net, the evidence from change blindness argues against a spatial map, an argument that is independent of the issue of visual stability. Future evidence, particularly at the neuronal level, may change this conclusion on the preeminence of updated retinotopic maps for visual s.tability, but for now these maps are the core of a working hypothesis?with emphasis on working."

Wurtz apparently thinks that if there were a spatiotopic map, change blindness should not occur. Therefore he rejects the spatiotiopic model. When he wonders how changes in the content of a spatiotopic map could possibly be missed, he seems not to understand that in order to report such changes one has to direct attention to the specific region of change in order to detect, remember, and report the change. So if attention is directed elsewhere in a spatiotopic visual representation of a scene, change blindness should be an expected result. This undercuts Wurtz's reason for rejecting the spatiotopic model of visual stability.

But there are other crucial factors that decisively favor the spatiotopic model.

1. Even with our eyes closed we experience a fixed volumetric space all around us. Notice that if we depend only on retinotopic information we would experience a

2-dimensional world rather than our famiiiar 3-dimensional world. This means that our retinal representations cannot be the final representation for our visual experience of a stable world, as the retinotopic model would have it.

2. Since we experience a 3-D space all around us, we are experiencing the world from an fixed egocentric origin/perspective. This kind of experience cannot be based on a fovea-centric/retinocentric perspective because the foveal origin changes with each saccade.

3. A spatiotopic representation is precisely the kind of brain representation needed to experience a stable environment/world from a fixed egocentric perspective.

4. A detailed theoretical brain mechanism (retinoid system) having the neuronal structure and dynamics competent to provide an internal representation of the world from a fixed egocentric perspective has been proposed, and it successfully predicts many previously inexplicable perceptual findings. Among these are the moon illusion, phi phenomena, hemispatial neglect, seeing-more-than-is-there, size constancy, Necker cube flips, etc.

5. The weight of experimental, natural, and clinical evidence supports the spatiotopic model of visual stability over the retinotopic model.

More about the spatiotopic model (the retinoid model) can be found in these publications on my Research Gate page:

Space, self, and the theater of consciousness (2007)

Where Am I? Redux (2013)

Thanks to Aaron - that is precisely what I was looking for...Thanks to all of you for your time and stimulating replies...

Aaron, I wonder if you have any thoughts about the relative merits of the retinotopic versus the spatiotopic explanation of visual stability.

Arnold - I read the details of your last extensively quoted response, and it was very helpful...Thank you!

Using some of the references cited above, I came across this recent article...Interesting that it was published as an "opinion" piece rather than a research paper...

Cavanagh et al. (2010) Visual stability based on remapping of attention pointers. Trends Cogn. Sci. 14:147

Charles and all,

Our experience of a stable world is at the very core of an understanding of consciousness. Here is my working definition of consciousness:

*Consciousness is a transparent brain representation of the world from a privileged egocentric perspective*

This is our phenomenal/subjective world. But our phenomenal world is such an omnipresent and intimate presence that we fail to appreciate it as the fundamental referent of our concept of consciousness. We each experience ourself at the perspectival origin of a surrounding volumetric space -- the world around us. But it is a physiological fact that we have no sensory organs to detect the 3D spatial plenum in which we live. So how is our brain able to represent the stable volumetric world of our common experience? My answer to this question is that we are born with innate system of brain mechanisms that represent our surrounding space from our own fixed egocentric perspective. This brain mechanism (I call it retinoid space) constitutes our subjectivity/consciousness. All of our perceptual representations are bound in proper spatiotemporal register and projected somewhere in perspective to our fixed self-origin within retinoid space. It is only *after* the output from our sensory modalities are projected into retinoid space that we become conscious of them. You can read more about the neuronal structure and dynamics of the retinoid model, as well as supporting evidence, in these publications:

http://people.umass.edu/trehub/YCCOG828%20copy.pdf

http://theassc.org/documents/where_am_i_redux

Arnold - Rather than choosing one or the other, I've taken the existing research to suggest that both representations exist are used in a complementary fashion; the lower levels of vision appear to be almost entirely retinotopic, but the higher you go in the visual system, the more spatiotopic the representation. Given the additional latency required to update the spatiotopic representation, it's not surprising that the brain would balance between the a faster (yet usually reliable) retinotopic representation and a slower but more robust spatiotopic one.

I hadn't seen your previous work on the retinoid model; I'm looking through some of your papers now. It looks like your model represents a potential way to represent both retinotopic and spatiotopic phenomena. I hadn't considered the potential connection between visual stability and consciousness, thought; I'm going to need some time to read this further and think it through.

Interesting!

To shed another light on the discussion, I would like to add that the question "why do we perceive a stable world" is not necessarily as profound or complex as you might think. It's similar to asking why we don't see our blind spot, or why we don't perceive motion when we make saccadic eye movements. I would say that at least a large part of the answer is that we see the world as stable, *because it is* and our brain has evolved to adequately interpret the world around us. Our representation of the environment doesn't need to resemble the actual environment. Or put differently, an unstable neural representation can perfectly well reflect a stable environment, just like the color blue can be represented in gray matter. So a priori there is no need to posit either spatiotopic (world centered) representations or 'remapping' mechanisms.

The issue becomes more interesting when you ask how we are able to combine visual input with other modalities and action preparation. In that case, there probably are mechanisms to deal with coordinate transformations etc. But it has little to do with conscious visual perception.

The review by O'Regan and Noe below is a good, albeit somewhat lengthy read. I have also published some work on this myself. Regarding this specific issue, the introduction of my thesis is probably clearer than our review paper.

- O’Regan, J. K., & Noë, A. (2001). A sensorimotor account of vision and visual consciousness. Behavioral and Brain Sciences, 24(5), 939–1031.

- Mathôt, S., & Theeuwes, J. (2011). Visual attention and stability. Philosophical Transactions of the Royal Society B: Biological Sciences, 366(1564), 516–527. doi:10.1098/rstb.2010.0187

- Mathôt, S. (2013, May 12). Visual attention and stability (PhD thesis). VU University, Amsterdam. Retrieved from http://dx.doi.org/10.6084/m9.figshare.704402

Sebastian: "I would say that at least a large part of the answer is that we see the world as stable, *because it is* and our brain has evolved to adequately interpret the world around us."

Your answer satisfies those who are not interested in *how* our brain is able to "adequately interpret the world around us".This is a profound scientific question that we want to answer. My candidate answer is the neuronal structure and dynamics of the retinoid system and its synaptically connected cognitive mechanisms. See *The Cognitive Brain* (MIT Press 1991).

I can see why you would interpret my answer that way, but that's not really what I mean. I think it's very interesting how the brain works in all its gory details. I just think that introspection doesn't necessarily provide us with a very good starting hypothesis.

To me, it seems that the search for a 'solution' to visual stability is driven largely by the expectation that the brain must somehow represent the world in a way that looks like the world itself: Stable world = stable (spatiotopic) representation. Whereas it might be that a continuously changing retinotopic representation is actually what underlies our sense of stability. Does that make sense?

(Btw, I saw that you have made the full contents of "The Cognitive Brain" publicly available. That's a very nice gesture, and I'm going take a closer look at it for sure.)

when you choose to move your eyes by "x" degrees, this information is simultaneously fed back to your visual brain which corrects for the movement (and displaces the image by the image by the same "x" degrees).

If you send this message to move your eyes, but the muscle is paralyzed, the image will appear to jerk, since the brain was prepared to see it in a different place and corrected for the movement, but the movement did not occur.

Also, iIf, instead of using your eye muscles, you bypass this feedback system by tapping directly on your eye, no brain correction is made for the shifted image and it will appear to move.

The corollary discharge (efference copy) signal that accompanies eye movement is one of the factors that is used to correct for motion, but it's actually more complicated than that. The other factors two are proprioception (the signal from the eye on where it actually is) and visual reafference (how much the world moves in response to your eye motion). The three combine in different ways to measure and account for motion of the eye, depending on the cause of eye motion.

As for pressing on the eye, for a long time it was believed that the world visibly shifted when you pressed on your eye because there was no corollary discharge from the eye to cancel the motion. However, that has turned out not to be the case. To quote Wurtz (who put it better than I) subsequent studies have "showed that the perceived motion of the visual world resulted from a subject’s attempt while fixating to counter the external push to rotate the eye rather than the rotation of the eye itself" (quote from Vision Research's article on Neuronal Mechanisms of Visual Stability": http://lsr-web.net/Assets/NEIPages/BobWurtz/pdfs/WurtzVisRes2008.pdf

Look at Fig. 3 in "Where Am I? Redux"(available on my Research Gate page). The central square appears to float *above* the background pattern and moves erratically without any tapping of the eye. The retinoid model of visual perception is the only model that I'm aware of that can explain this phenomenon. Does anyone know of another explanation?

Dear Charles Taylor, This issue is the main topic of my research. The answer to your question can be found in my review "Motion perception during self motion: the direct versus inferential controversy revisited" By A.H.Wertheim. Behavioral and Brain Sciences 1994, 17, 293-355 and later papers, See my site http://www.fss.uu.nl/psn/web/people/personal/wertheim/Home_page_of_A._H._Wertheim/welcome.html

Regards,

Alex Wertheim

Alex, you wrote the following as a summary of your model:

"In sumrnary, then, the present rnodel holds that reference

signals are cornpound signals, which rnay include

(any cornbination of) an efference copy, a vestibular, and a

visual cornponent. Figure I illustrates how such reference

signals rnay be generated."

While I agree with this summary as far as it goes, it seems to me that this formulation omits the critical component of an internal representation of a global volumetric egocentric space. Don't you think that the compound reference signals must control the perceptual contents of such a space? In the retinoid model, these reference signals would selectively activate the shift-control neurons to maintain the proper perspectival registration of visual events in 3D retinoid space.

Are you taking in account that movement perception is also related with our inner ear sense (semicircular channels and equilibrium)?

Yes, these inner ear mechanisms make up the vestibular system. head and body motion evoke the vestibular signals that stimulate the shift-control neurons that enable the retinoid system to maintain a proper egocentric representation of the environment.

I have another question: When people daydream and interrupt the daydream by trying to locate the object they are looking at, they generally find it difficult to do so. It is only after a fair amount of concentration that they manage lo actually see what they had been looking at. What is more: 1) This object always lies on an intersection between two contrasting media (e.g. a line on a rug separating two patterns or colours; and 2) they locate the focus of only one eye, and it takes them some additional effort to locate the focus of the other eye, which is close by the first focus. I therefore have 2 questions: 1) Why is it so difficult in this interrupted-daydream situation to see what we are looking at? And 2) If, having located the 2 foci, the seer brings these 2 foci into focus at the SAME time, i.e. he or she becomes conscious of seeing the 2 objects at the same time, could that help to bring about some kind of left-right-brain integration, a kind of brain gymnastics that could help to resolve a problem of perceptual or cogntive dissociation. A penny for your thoughts. I am a psychotherapist, not a vision specialist, but I hope that your vision input can help me to help some of my clients get their act together.

When you are deep in a day dream, you are not really looking at anything in front of you. You are experiencing the other world of your recollected images. When you interrupt your daydream, you have to recall what you were paying attention to before and locate it again in the physical world. When you day dream, your self is in a different phenomenal place than your body. See "Where Am I? Redux" for an explanation of how the brain changes the location of the self.

Thx Arnold, but what about the possiblity of (right-left-brain) integration or any other kind of integration through deliberate simultaneous bi-focusing? You did not comment on that.

The appeal to hemispheric integration (right-left-brain) as an explanation for visual fixation is not well founded without a detailed account of relevant brain mechanisms that occupy these brain regions.

I believe that the answer to this question is related closely to other phenomena. When we watch kestrels hovering above the ground it is amazing to witness how stationary the head is in relation to the rest of the body. Also, when dogs are chasing frisbees they all adopt the strategy of running in a direction and at a speed that has the effect of keeping the frisbee at a fixed point against the sky.

The Fractal Catalytic Model treats cognition as a process of mediation the success of which is measured by the degree to which a cognitive state preempts stimulus. The cognitive process is one which involves the identification of 'fixed points' or points of invariance. These fixed points may not be literally points, they are spatio/temporal points and relations that remain fixed over time and through transition. Thus, the middle of a wheel is the fixed point around which rotation is mediated - it is also the fixed point around which our perception of a spinning wheel is mediated.

Associated with fixed points are a whole set of 'primed' cognitive states and expectations. Thus, if we have decided that we are looking at an animation of a young woman rather than an old lady (as per the old optical illusion) then what we expect to happen should the animation move will be dictated by a set of fixed relations corresponding to that particular cognitive stance.

Imagine the sailor finding his sea legs. A normal land-lubber takes his/her cues from the environment in order to effect bodily balance. In this case the chosen fixed points are external to the body. However, taking cues from the environment to establish what is up and what is down is not a good strategy inside a ship. The young sailor learns to reject the usual strategy of using a fixed point external to the body and elects the center of gravity of his own body instead.

Our environments appear stationary to us because we have chosen aspects of the environment as the fixed points of mediation of our cognition.

I also think that this is the way forward to understand the nature of 'the attention'.

Understanding the 'attention' this way has the advantage of involving a point which is central to the cognitive state and yet which is itself NOT an object of attention.

If this approach is useful then we would expect that sailors that have 'found their sea legs', when inside a ship in bad weather, should report that, contrary to what most people experience, their immediate environments move with the motions of the ship.

Continuing from above:-

I think that we can account for the bad reaction that some people had when they watched the film 'Cloverfield'.

Cloverfield was filmed with hand held cameras that were always on the move - often erratically. Because there was no way for the audience to predict the motion of the camera there was consequently no way that the brains of the audience members could establish fixed points around which cognition of the film/environment.could be mediated. Cognition of the audience members kept breaking down because the scene could not be predicted.

Those members of the audience that involved aspects the film in their own processes of orientation (difficult not to do if the screen covers a large percentage of the visual field) were made to feel sick.

The central role that anticipation, pre-emption or prediction plays is the process of cognition is very much underestimated, I think.

Cognition does not follow stimulus - cognition preempts stimulus.

It is simply a question of optimization of the mathematical complexity. It is much more complex to move all the objects when the observer moves, as when you move only the observer in a stationary object environment. In addition to that argument, body receptors signals the movement of the body.

I don't think that is necessary. Did you read my review from 1994 in Behavioural and Brain Sciences,17(2):293-355. If you read it you'll find out why.

Greetings, Alex Wertheim

So, try as I might, I cannot perceive this stability. Certainly, many aspects of the perceptual backdrop are relatively more stable than others, but I think that more is fluctuating than we give it credit, and more of our body is sensitive to more of those fluctuations than we give them credit. I feel that the proposition that the background is stable is less a fact and more a premise--as premises go, it suffers from being the cause of much overbuilding of the cognitive architecture. A corollary premise to this one is that perception is "in the instant" and ends abruptly past the cliff of whatever predictive mechanisms appear in said architecture.

Response to the original question:

When you decide to move your eyes, the same signal which activates your eye muscles is also sent ( by recurrent collaterals) to the brain to prepare it (by the same amount and direction of the movement) to anticipate the displaced image.

If instead of consciously moving your eyes , you instead move the eye by gently tapping the side with a finger, the brain cannot anticipate or correct for this displacement . The world will appear to jerk.

Conversely, if you send a signal to your brain that your eye is going to move, but the muscle is, in reality, paralyzed so that your eye remains in the same place, an experience of movement will also occur, since the image did not appear in the updated location as expected.

Objects which move on their own, tend to appear in different places with respect to a stable background - like a person walking in front of the building- . the background doesn't move, but the person keeps appearing in different places with respect to the building , so we infer that the person moved but that the building is stable. .

Actual movement is not necessary to experience the sensation of movement. Check stroboscopic effect (motion in film), phi phenomenon (apparent motion when light jumps from one light bulb to another or the autokinetic effect (when the precise position of an airplane against the sky appears closer or further- because it cannot be evaluated against a background. )

Correction (meant to write "corollary discharge": instead of "recurrent collateral":

Joyce:L : "When you decide to move your eyes, the same signal which activates your eye muscles is also sent ( by recurrent collaterals) to the brain to prepare it (by the same amount and direction of the movement) to anticipate the displaced image."

Unfortunately, the suggestion that the brain *anticipates* a displaced image is not a useful explanation because we need to know what *anticipation* means in terms of brain function. An explanation of visual stability in terms of putative brain mechanisms is given in "Modeling the world, Locating the Self, and Selective Attention: The Retinoid System" on my RG page.

Arnold - aren't you neglecting a fairly large body of literature about corollary discharges being a mechanism that is important for visual stability. With due respect, I'm not sure that your retinoid system is the last word on things.

Charles: "Arnold - aren't you neglecting a fairly large body of literature about corollary discharges being a mechanism that is important for visual stability. With due respect, I'm not sure that your retinoid system is the last word on things."

I'm not neglecting corollary discharge; it is necessary but far from sufficient as an explanation for perceptual stability. It is assumed to be an important initial event for all candidate models of visual stability. The retinoid system might not be the last word, but it is currently the most comprehensive explanation for perceptual stability. And it actually provides a detailed model of the minimal neuronal structure and dynamics needed for our conscious experience of a stable volumetric world around us. It also accounts for many previously inexplicable phenomena, and it has successfully predicted novel perceptual experiences. What competing model would you offer?

Here is what Wurtz had to say about visual stability in *Vision Res.* (2008):

"Saccadic displacement is the more central, more difficult, and

more interesting problem, both historically and presently. It is

hardly surprising that the neuronal mechanism has not been identified,

and here we still do not know whether there are multiple

neuronal mechanisms. There are two salient neuronal candidates.

First are the neurons in frontal and parietal cortex with shifting

receptive fields that provide anticipatory activity with each saccade.

These could provide support for the retinotopic hypothesis

of visual stability based on updating a retinotopic map. The anticipatory

shift in activity might also provide the memory for the

transsaccadic memory hypothesis of visual stability. The second

neuronal mechanism is provided by neurons whose visual response

is modulated by eye position (gain field neurons) or largely

independent of eye position (real position neurons). These neurons

could provide the basis for a higher order map for a spatiotopic

hypothesis of visual stability."

So Wurtz posits "two salient neuronal candidates": (1) a lower-order map based on updating a *retinotopic* map by by means of shifting receptive fields, and (2) a higher-order map based on updating a *spatiotopic* map. The retinoid system is type 2. It gives us a 3D spatiotopic map in which all objects and events are represented subjectively; i.e., in egocentric coordinates. And it explains the moon illusion and the SMTT hallucination.

You may all be interested in Vision-Space (as opposed to picture space). A new form of illusionary space based on perceptual structure and not optical projection. We generate this perceptual structure as biological systems. Vision is entirely non-photographically rendered. When we actually study the data structures of phenomenal field (vision) we can understand that peripheral vision is actually a field structure that's set out radially from fixation (no maps involved!). Spatial awareness here is 'implicit', its a simultaneously holistically understood medium. Movement is understood in flow. Central vision is 'explicit' in nature and motion is tracked. We need both systems up and running. We have developed post process software that's capable of taking in optical record and transforming it into Vision-Space moving image media mimicking (we think) visual awareness. I attach a list of web presentations and there are downloads to articles in the library section on www.pacentre.org. (also on the RG profile). We are attempting to speed up the programming architecture to work at realtime speeds and hence simulators and then we will be able to produce some meaningful stats! In short, differences occur between camera projection tech and our visual system because they have next to nothing in common.

Sorry attachment failed!

John,

I assume that Vision-Space is a system of particular kinds of neuronal mechanisms in the brain. How does it differ from retinoid space? How are changes in the perceived size of retinal after-images as a function of fixation distance explained by the Vision-Space model? How does Vision-Space explain the moon illusion?

Have a look at the presentations and the papers Arnold. "Having the courage of your perceptions" & Retinal processing -A theoretical proposition for retinal detection of a field potential unfolding from the light array to form the basis of spatial and orientation awareness within the phenomenon of vision. I do attempt to link this to the moon illusion. As you know the moon is a very special 'object' for the perceptual system.

Vision-Space derives from a mixture of intuitive record and computational vision science. The computational aspect relies on aspects of Prof. Jan Koenderink's work. I believe that we have a the basis for a system that models visual awareness. However at present this is just an illustrative programming architecture only. Its in the form of post process software that takes in optical record and totally reconfigures it. We are in the process of getting this to near real-time speeds for use in simulators as this will enable us to conduct some initial meaningful evaluation work. What we really need to do is to move towards an academic programming architecture that takes us towards a system that reflects what is know about neuronal mechanisms. In short we need to get to the point where we have a graphics engine where the 'picture' is never formed, a situation where Vision-Space is outputted directly from the engine. We have just a starting point at present but it works! I would welcome your thoughts.