Showing posts with label vision. Show all posts
Showing posts with label vision. Show all posts

Wednesday, October 20, 2021

mixed signals

 The other day I walked into the kitchen to see the following mundane happenings:

1) Daughter sitting at the kitchen counter eating a snack out of a bowl.

2) Wife sitting on a kids chair with son in lap, clipping his toenails.

These were about 8 feet apart. I casually looked at one, then the other, then back again, and got a flash of revulsion at having just seen my daughter casually clipping and eating toenails!

This incorrect impression instantly resolved. The higher level aspects of these two distinct happenings were briefly entangled. There are many ways to explain this, two come to my mind:

1) On foveating an event, the higher-level contents (recognizing-what-is-happening) are present in my experience, but on looking away, they are reduced and only a vague 'pointer' is retained (so that I can look back at the interesting event to re-experience the full thing). In this case, the reduction was delayed or incomplete, so that when I looked at one event, the previously foveated one was still in-mind, and so they briefly overlapped. Since the higher-level contents are strongly enforced by the lower-level contents, which are completely forced by the retinal input, the intermingling was brief and the 'correct' contents survived.

2) Different events can simultaneously be in experience, but they are normally cordoned off from one another. In this case, the cordon was briefly broken and the two sets of high-level contents were mixed - maybe from one leaking into the other.

I think that 1) is the more likely alternative. I doubt that multiple sets of high-level contents can be simultaneously experienced, since they inevitably will sometimes involve common contents (in this case, both would have involved 'person/child/fingers/kitchen/etcetc'), and so would naturally be inextricable. Instead, my impression that I can simultaneously entertain different sets of high-level contents must instead be due to keeping one set in detail, the object of attention, while the other is reduced to something more like a pointer which can be quickly grabbed by attention to reconstitute the whole set.

Thursday, July 22, 2021

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When I started grad school, one of the first things I did was to adopt a kitten that had been born earlier that summer in the apartment across the hall. Now, 18 years (!?!) later, here is a Eulogy for my Cat, in the form of a couple of cat-related anecdotes from my studies.

In my first year of school I was getting into the science of spatial vision - acuity, contrast, retina, V1, etc. I learned that a cat's visual acuity is like 5x worse than a human's. So, naturally, I figured that everything must look *blurry* to a cat.

See, I lived with this creature, and I would often think, how do things appear to her? I remember walking home late one night thinking about how stars appear to me as points - must they appear to a cat as blurry spots? And I realized that this couldn't be the case.

When I take off my glasses and see a point of light, it looks blurry in that I can see that what should be a point is actually smudged across a region of the visual field. And to see that smudge as a smudge, I must be seeing details within the region it fills.

If something appears as a point, that means that it has no apparent interior. So in fact, the acuity limit is telling us about the spatial resolution of appearance. Some visible thing that's smaller than the acuity limit must appear as a point. 

Without glasses, a point is imaged on my retina in a smudge that's a good fraction of a degree across. But my true visual acuity is in the range of 2 minutes of arc; so I see that smudge as an extended, 2d thing. My cat wouldn't see the smudge - she'd just see a point.

Now, years later I'm still making use of that insight, for example when I have argued that peripheral vision can and should look just as sharp as foveal vision - it's for the same reasons that a star should look like a point to my cat.

Another one, now about my perspective rather than the cat's. Some version of this is familiar to any of us: you see a dark shadow at night - is it the cat? or is it something else? There was one instance of this that I puzzled over for years.

I had a pair of shoes that I would sometimes leave by the wall in the hallway of my apartment in Boston - now we're in my first postdoc, 10 years ago. Time and again, I would see those shoes out of the corner of my eye and think, "Cat!" - then foveate and see, "shoes!'.

What fascinated me was that after the first time, I knew what was going on. That is, the high-level visual part of me knew they were shoes. But over and over, my early visual system was fooled - that brown shape of a certain size, on the floor, was most likely "Cat".

I started to collect these cases, where peripherally-seen X makes me think I'm seeing Y, even once I know X is really X. I posted an good case here a while back: (https://twitter.com/AndrewHaun3/status/1261891022625398784). But the prototype will always be Shoes->Cat.

Anyways, before I was so theoretically rigid as I am today, I used to wonder: when I thought the shoes were my Cat, did they actually *appear* as a Cat would appear? Did my mistaken recognition subtly reshape the spatial patterns so as to make them a better fit for "Cat"?

It does seem like this sort of thing can happen to some degree, e.g. with Ryota Kanai's "healing grid" illusion. But wholesale, at the object level? How could we find out? It doesn't matter, because I don't think that's what's happening here.

What I think is happening here, rather, is that I am experiencing a spatial form that is shoes-shaped, shoes-textured, etc. And it's decidedly not cat-shaped, cat-textured, etc - it's not clear cut pareidolia, as where I might see the Cat-shapedness of a Cat-shaped cloud. 

With the shoes, they're the right size and location for a Cat, and my super-sensitive Cat-recognizers are activated, and I experience recognition-of-Cat at the same time I experience a shoes-shaped, shoes-textured spatial gestalt. It's not a wholly congruent experience.

Even now, this week, when my Cat is no more, I've already made the mistake of thinking that a shadow in the hall was "Cat"; that a light *thump* in the other room was "Cat". Now, not only is it a mistake, it's an impossible mistake. But the brain does what it does.

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Wednesday, July 22, 2020

A point on interpreting inattentional blindness studies

On Inattentional Agnosia

In a recently published study, Cohen et al showed that, under very naturalistic conditions (viewing 3D natural scene videos in VR), observers often fail to notice that the entire periphery of the visual stimulus has been rendered colorless, i.e. completely desaturated. Cohen et al conclude that the visual periphery is far less colorful than one might have thought. They state this conclusion in several ways:

“these results demonstrate a surprising lack of awareness of peripheral color in everyday life”
-here qualifying the phenomenon as ‘lack of awareness of peripheral color’. Later, they say it less ambiguously: “If color perception in the real world is indeed as sparse as our findings suggest, the final question to consider is how this can be. Why does it intuitively feel like we see so much color when our data suggest we see so little?”.

So, Cohen et al believe that their data suggest we see very little color. This particular claim is logically absurd, however. I explain why in the following:

Cohen et al clearly believe that the phenomenon they present is a case of inattentional blindness. Inattentional blindness phenomena are frequently encountered in visual experience, and are not difficult to bring about in experimental scenarios. Typically, an observer is shown some stimuli connected to an explicit or implicit task; during the course of the task, some unexpected stimulus is inserted, and the observer may fail to notice. These failures to notice are often very retrospectively surprising, since once the observer knows what to look for (once they’ve been debriefed) it is easy to see the missed stimulus. Experimenters often conclude from these results – both the failures to notice and the retrospective surprise - that, in one way or another, the observers (and the rest of us) must see far less than they think they do. But this is not the kind of conclusion that Cohen et al are drawing.

The most famous example of an inattentional blindness phenomenon has got to be Simons and Chabris’ gorilla. In their experiment, observers watched a video of several people playing a ball-passing game. The players move around constantly, throwing the ball back and forth; the observer’s task is to count the number of times that certain players catch the ball. With no warning, halfway through the video, a person in a gorilla suit wanders into the middle of the ballgame, stops and waves at the camera, and then wanders back out of the frame – the ball game continues. Many observers do not notice the gorilla at all!

Simons and Chabris used this and similar results to advance a version of the “we see less than we think” argument. But what if we transplant Cohen et al’s conclusion to the gorilla experiment?

Here is a sentence in general terms that describes both studies:
“Observers viewed a complex stimulus that engaged their visual attention. After a while, a change was introduced to the stimulus that was retrospectively obvious. Many observers did not notice the change.”

Now, here is the reasonable, broad conclusion (a la Simons & Chabris):
“We must not notice as many things as we would expect based on what seems to be obviously noticeable.”

And here is the unreasonable, specific conclusion (a la Cohen et al):
“We must always be having the kinds of experiences evoked by the changed stimulus.”

In the Cohen et al study, they replaced a colorful scene with a colorless scene; observers didn’t notice; so, according to their reasoning, we must actually be having colorless experiences all the time (or more precisely, experiences of “so little” color). Otherwise, the reasoning seems to go, we would notice the change from colorful to colorless. We don’t notice it because it was colorless all along (they do include a caveat that maybe it’s the other way around, that even the grayscale scene evokes a colorful ‘filled-in’ experience, but that doesn’t seem to be their favored interpretation).

For the gorilla study, a gorilla was introduced incongruously into a ball game; observers didn’t notice; so, we must actually be having experiences of incongruous gorillas all the time (or, maybe more precisely, experiences of gorillas in ball games?). Otherwise, we would notice the change from a no-gorilla to an incongruous-gorilla scene. I don’t want to go on with this because it’s obviously absurd. But isn’t it the same logic as the color argument?

The absurdity comes in part from arguing from a complete lack of evidence: they are taking absence of evidence (failure to notice the change) to be evidence of absence (of color experiences). The experiments they are doing have no bearing, it seems to me, on whether or not their observers are actually experiencing color in their peripheral vision.

But more than this, the absurd conclusion comes from a lack of engagement with the important concepts at play. Color, most importantly. What does it mean to see color? That's for another time, I guess.

Before I finish here, an attempt at charity:

Perhaps the logic Cohen et al would derive from Simons & Chabris is somewhere in between the broad & reasonable, and the narrow and unreasonable:

"If we do not notice something, we are not experiencing it."

This is a strong claim, which I know that Cohen et al and many others would more-or-less endorse. But it does demand some engagement with some basic questions: if one's experience is colorless, what is it like? Is it like experience of a monochrome scene? Why are shades of gray excluded from 'color' status? What is special about 'chromatic hues'? Is there really less to seeing a monochrome scene than there is to seeing a color scene? Think about it: if you are seeing a spot as blue, that precludes your seeing it as any shade of gray, just as much as it precludes it from being yellow or red or whatever. Each part of the visual field always - it seems, at least - has some color in the broad sense.

In fact, Cohen et al did find that subjects always noticed if all color, in the broad sense, was removed from the periphery, i.e. if it were replaced with a flat gray field. Which would seem to defeat their basic conclusion that we are not seeing color, or much color. So, again, what is supposed to be so special about chromatic hues? Interesting questions, definitely.

Thursday, March 05, 2020

A dialogue! (old but good)

I ask you to point your eyes up towards the clear sky and to tell me what you see. “An expanse of blue,” you say. I nod and say, “Ah, so simple. Blue is just one thing – your visual experience is so simple. Is that surprising?” 

This doesn’t sound right to you. You shake your head. “No, it’s not simple. There’s blue everywhere. Every location is blue; every part of the space is blue. It’s clearly not simple – it’s a vast structure of blue spots. I’m not even sure how to describe it to you.”

“Well,” I say, “you’re most likely confabulating this description. Through your life experience with using vision, you know that the sky is extended spatially, and that if you move your eyes around you’ll still see blue, and you know from moment-to-moment that the last thing you saw was what you’re seeing right now – simple blue – so you are illuded into claiming you see an expanse of blue. But you actually see no such thing.”

“How can you claim this?” you ask. “Why should you doubt what I tell you?”

I shake my head sadly. “Subjective reports are known for their fallibility. People often claim to have seen things that they could not have seen; they claim their experiences have qualities that they cannot have. But I’ll suspend my disbelief for a bit. Can you convince me?”

You seem a little annoyed, but you nod. “Perhaps.”

“Okay. How many parts are there to this blue expanse?” I ask. You don’t know. We go through some basic tests and it seems that you can’t really tell me about more than a handful of spots at once – yet you persist in claiming that the actual number of blue ‘spots’ is vast.

“Are they all there at once?” You seem to think that they are. “Could it be that the parts are there only when you look for them?”

“No,” you say, “it feels like a big, continuous expanse of blue. It’s not a little searchlight.”

I proceed. “But I’m asking you to convince me of that, not just to tell me again and again. As far as I can tell, you can only report the color of a few spots at a time – a big ‘sky-sized’ spot, or a few little ‘point-sized’ spots. But your momentary capacity seems to be extremely small – where is this huge expanse? And how does it make any sense that you should experience such enormous complexity, but be able to interact with only a vanishingly small portion of it?”

You seem unsettled: “Why,” you ask, “would I claim to see an expanse of spots when I only see a few at a time? What do I gain by confabulation?”

“But it’s a meaningful confabulation – you are unaware of the limits or boundaries between your momentary visual experience, your memories of recent experiences, and your expectations of what future experiences will be like. The reports you generate are more a confusion of these different processes, rather than a confabulation.” I concede a word, but little else.

“Well then,” you say slowly, “what does this confusion feel like? Might it feel like an expanse of blue? Or do you assume that only the perceptual process constitutes experience?”

I miss your point. “But we’re exactly talking about perceptual experience – of seeing blue – don’t try to shift the goal posts.”

“No, we aren’t talking strictly about perceptual experience, though I do think my experience is fairly categorized as perceptual rather than memorial or expectative. You’re the one who introduced other ‘processes’ into the conversation.”

“Well, this can’t work,” I say. “I can concede the process thing, but this doesn’t address the reportability issue at all, and it’s highly implausible, even worse than if you put everything in ‘perception’. Are you claiming that you experience all your memories or all your expectations, at once?”

“No no,” you dismiss the idea with a wave of your hand. “I was just asking – what do you think such confusion should feel like?”

“Like what you’re feeling now,” I say.

You roll your eyes. “Come on. Clearly the confusion you’re suggesting should feel very different from what I am feeling – or no, from what I claim to be feeling. Otherwise we wouldn’t be having this debate.”

“Well, I can’t say exactly. You are experiencing what you have access to, and you can report what you have access to; so your experience must be of a narrow set of blue spots. And you claim otherwise because whenever you check other spots, you immediately begin to experience them – so you mistakenly believe that they were there all along. Your experience isn’t what you think it is – and it isn’t what you claim.”

You seem perplexed. “Does that mean that unless I am queried about my experience, I am not under this illusion? I only become mistaken when asked to describe what I’m experiencing?”

“Maybe?”

You decide to change tack. “Okay. Can you tell me what substantive difference there is between this illusory or mistaken experience and an actual experience of a blue expanse?”

“Well, it would be a huge difference – the illusory experience is actually very limited and consists of very few parts, including the few blue spots and a particular set of expectations and memories that lead you to claim that you see an expanse of blue. The actual experience of a blue expanse would be just that – many many more spots, and no necessary memory or expectation aspects, though you’d probably also have those in addition.”

“I can’t help but think,” you say carefully, “that you’re doing something slippery here. You want to know why I claim to see a blue expanse, and your explanation has to do with these non-perceptual processes and how they seamlessly support my very limited perceptual process. And you reject my explanation for my claim – that I really am experiencing a blue expanse – because I can’t report the whole expanse to you. But can I report all my memories and expectations to you? Do you know how to collect such data?”

“I think that the fact you’re able to so quickly report on what you see at randomly cued locations suggests that those processes must be at work.”

“Surely they are, and I can tell you that I do indeed have experiences of memory and expectation. But I’m wondering why you think you must reject my explanation but are satisfied with your own.”

“Certainly I’m not satisfied – there is much to learn. We really understand perception etc rather poorly at this stage.”

You shake your head.

Thursday, April 18, 2019

Parahypnic Hallucinosis?

Remember this episode:
http://xuexixs.blogspot.com/2018/08/blinking-plants.html

That was my bout with what I termed 'gardener's hallucinosis', where I spent all day pulling clear weed and etc from the gardens, and wound up with vivid blinking hallucinations. I likened it to the 'eyes open' geometric hallucinations I sometimes had back in my migraine days.

Well I've noticed a few times lately something similar happening under a specific circumstance. The circumstance is: I fall asleep in my daughter's room as I read her to sleep. I wake up a couple of hours later, stumble to the bathroom to brush my teeth, and I go get in my bed.

It doesn't happen every time, but sometimes - and last night very vividly - on waking in this way I have vivid and complex geometric hallucinations. Fine-grained, colorless - much of the content is just of very, very fine beads or dots, flickering and moving - but mixed into it are larger-scale features. Last night, the features were like a high-pass Kandinsky painting: discs and long, smoothly-curving lines, all moving and twisting around randomly, but no particular surface colors except for grayness, or darkness.

I could see it all fairly clearly with eyes opened, until I turned on the bathroom light and then the experience faded.

Maybe not coincidentally, I have been having minor headaches lately, and I think there was one yesterday. My brain must be in a state?

Monday, August 13, 2018

Gardener's Hallucinosis?

Interesting experience yesterday, Sunday.

Spent ~5hrs outside in the gardens, pulling weeds. Had done the same for a few hours on Saturday. When I came inside for good, about 5 or 6, I started to hallucinate during blinks - when I blinked my eyes, especially when not prepared for it, I would see images of the plants I had been pulling all day. Sometimes very clear, seeing leaves with their serrations and textures, and tendrils curling around - the images were coherent and (mutedly) colorful, seemingly randomly selected but each was a recognizable one of the real plants I had seen, mostly members of the 2 or 3 most common weeds of the day.

Sometimes the images were strong enough to be distracting, making it hard to see - or to recognize - what was actually before my eyes. But I think they were only actually visible during the blinks. I managed over time to notice some properties of the images - I could hold my eyes closed after an effective blink. It was still unclear to what extent I was *really* seeing the fine details, or whether the actual images were coarser and just 'suggesting', as in normal visual imagery, the fine details. Holding my eyes shut, it seemed that the form of the afterimages or noise, in the eyes-shut darkness, guided the structure of the hallucination: spots of afterimage seemed to appear as leaves, streaks as stems or tendrils. But it was not so clear as to be certain of this.

The experience lasted until I went to bed, 6 or 7 hours later, but it had attenuated by then. I slept and remembered several dreams that had nothing at all to do with plants (one I remember, now, was that my lab seemed to be based in the house I grew up in, and some newcomers were using space in the den - dream-Giulio warned me not to give them to much space, or they'll think they can take more). When I woke up this morning, the phenomenon returned for another hour or so, but is gone now.

The phenomenon resembled, to me, the kinds of hypnogogic hallucinations some people have after long, repeated activity ('the Tetris effect'), but I can't find reports of this in normal waking experience (albeit during blinks). I described it to Giulio and others, the physiological explanations are kind of clear, but as to why it happened to me and why it isn't much more common, that's an open, strange question.

Another thing it reminded me of, was back in the migraine days, seeing geometric web patterns after waking, sometimes during blinks. Similar kind of dynamic, but I don't think those experiences ever lasted more than minutes, definitely not many hours.

Wednesday, February 17, 2016

challenge

Irwin Borish versus Edwin Boring.

Go!

Tuesday, December 17, 2013

meaning and filling-in

Something I've been meaning to write about for a couple of weeks now: object meaning as filling-in, and how this idea is the explanation for cases of deja trompe.

We return to the idea that the visual field is a stack of properties that develop from one another along a relatively rigid hierarchy. So, a certain configuration of brightnesses, which can be seen as such (as brightnesses, or darknesses, or colors), can also be seen as an edge or some other broadband feature. In fact, given certain configurations of colors, given broadband percepts are compulsory and there is no choice but to see them. However, they do not exclude the more local aspects that seem to compose the features. From edges we go to surfaces and depths, and from there to objects and meanings and utilities.

All these levels of the visual hierarchy are experienced simultaneously and constitute conscious qualia - we are experientially aware of points of color or brightness, and we are aware of edges and lines independent of the surfaces they bound, and we are aware of surfaces independent of the objects the bound, and we are aware of objects (in the sense of depthful 'thingness') independent of the meanings they bound (what they "are"). But the independence of these qualia exists only in their separability, because in normal experience they are not causally independent - when a given configuration exists, the other levels are evoked compulsorily, and so qualia are correlated between levels.

Illusion often consists of violations of these correlations. So, we will see illusory contours where there are no variations in color or brightness to constitute them. Deja trompe, as I have described it, is seeing an object as something other than what it "is", and doing so repeatedly, involuntarily, and being aware of this repeated mistake (this is the literal meaning of the term). In the case of illusory contours, the normal correlation or association between patterns of color and edges can make one feel that something at that level is seen, i.e. that there are color or brightness qualia there, though I don't see them (what I see is an edge without any color variation). On the other hand, we certainly see the colors in the watercolor illusion, or in other filling-in effects, so it seems that it does happen that we can be tricked into generating qualia without the normal hierarchical causes, both up and down (and within) the hierarchy.

In seeing an object for something that it is not, what is happening? When I walk through the hallway to the kitchen, and see my cat sitting on the floor in one of her usual spots, looking up at me as I pass, only to realize in a fraction of a second that no, that's not my cat, those are my boots - what am I actually seeing, during the duration of the mistake? I see something there, a thing with similar color and size and shape as a cat or a pair of boots, and in a suitable location for either. So, am I seeing a cat, and then seeing a pair of boots? Or am I seeing a pair of boots, and thinking it's a cat, and then thinking it's a pair of boots? Or am I seeing something indeterminate and relatively formless, that can be either thing (deja trompe is really a creature of peripheral vision, so crowding is of course a thing)? What is seeing? What is thinking it is?

Obviously, I have an opinion. And, being a kind of expert in this sort of thing, it's an informed opinion. I think that seeing boots for cat, my low-level qualia are entirely boots-driven, so in that sense, I am seeing boots. If you put the boots and the cat side by side at the same location in the visual field, I am confident that I could discriminate them, though there's a test there. Actually, that's a nice idea: take the objects that are confused in a deja trompe, and measure their actual discriminability. So it could be that they are relatively indiscriminable, and what is seen is relatively indeterminate and formless.

Actually, whether the low-level qualia are distinctly bootslike or indeterminate doesn't matter much to my interpretation, just shifts things around a little. What is certainly not happening is that the low level qualia are going from being more catlike to more bootslike, or that they are changing at all. That is the striking thing here: that the low-level qualia do not change, although they seem to change, in what is either a metacognitive or memorial judgment. What is changing is the meaning of what is seen, and that is what is so interesting here. Because the low-level qualia are not sufficiently specifying the identity of the object, it is briefly mis-specified, something which almost never happens in normal visual experience. Once you know what something is, you virtually never mistake it for something else, except in cases where you do, and when that happens you note it or mention it to whoever else is in the room, because it's so surprising.

When it happens, deja trompe gives a strong impression that what is seen is changing from one thing to another. However, it only makes sense that this is happening at the highest levels. The lower-level qualia, I will maintain (when given the chance) are more determined by the sensory input, and the later qualia are determined by the lower-level qualia (and certainly also by other mechanisms that do not present themselves in consciousness). So, through this chain, errors or lack of specificity can build up, and you wind up with a mistake, at the top.

What it comes down to is that meaning, i.e. what a thing is, is a sort of filling-in, where in exactly the same way as the watercolor effect, but much more solidly and more vigorously, the multi-level boundaries of an object prompt it to be visually filled with meaning. I mean this literally, and I think it is obviously true: when you see a scene filled with objects, all of which you recognize, their identities are there within, in the same locations as the objects. So an object made of a certain size, and in a certain spatial location, and colored black and brown, is painted with bootsness, and that is what makes it boots. If I mis-paint it as cat, that is what makes it cat - nothing about the lower-level qualia, the shapes or the colors or the general configuration of the object's visual structure, are really directly associated with that meaning. You can destroy certain parts of my brain, and I will still see things as objects, but I won't know what they are.

So, these instances of mistakes in identification are interesting in how they reveal the dissociation between objects in themselves, and objects as they have meaning. An object in itself is still a perceptual construct, but it is meaningless. It only as existence in relation to other perceptual constructs. This is a middle place between the physical stuff to which the object presumably refers, and which is even more meaningless in that it has no relations at all to other stuff - there is simply stuff, and any effort to clump it into this stuff or that stuff is exactly that: effort, something done by an agent. So the object in itself is the way the brain deals that stuff into a usable form, and the meaning of the object, what the object is, is the set of all known relations of the object in higher levels: past and future, the stuff of cogitation and memory, beyond perception that exists only in the immediate moment.

That's enough of this. Just been thinking about these things on the train lately, needed to get it out of my system (or at least articulate it into something interesting - the discrimination experiment based on actual instances of deja trompe might actually be a good idea).

Tuesday, November 12, 2013

lazy tuesday monocular

spent the last few hours with a patch over one eye. a bit bored and depressed, figured why not?

1. noise, of course. the noise is very interesting, and if i stare at one point for more than a few seconds, strong rivalry begins. the noise is very fine grained, at the limit of resolution, but has strong lower frequency structure, 1cpd or less. it oscillates and swirls, like fine sediment in water or mist when you wave your hand through it. interesting. it gets stronger when looking (with uncovered eye) at something very high contrast.

2. false double vision. if i'm fixating the screen, as now, and bring up a finger in front of my face, it is confusingly not transparent or doubled. yet, it feels as though it is. my left eye, covered, is open all this time, and apparently i have a strong, strong expectation of double vision even when monocular. one thing that keeps happening is that if, as i often do (especially when tired), i start to gaze into the distance behind my screen, a condition where usually the screen would slide into diplopia, i still have the sensation of the diplopia slide, despite having only one eye's view. it's a very strange sensation, of the field sliding while not moving at all. hard to describe.

3. false motion. there's a spot in the eyepatch, about 30 degrees or more above and left of straight ahead, where a bit of light creeps in, so there's a spot there. when i move my eyes around, the spot seems to move back and forth. of course, it's just my eye moving back and forth, but its motion isn't being 'cancelled' in the same way as motion in the uncovered eye, i.e. saccadic suppression doesn't seem to be working over there.

the noisy view from the covered eye is different between fovea and periphery. it's similar to what i've described in other entries about the intrinsic light, how it seems clustered and of a different brightness - even opposite polarity - than the surround.

at times the noise is overwhelming, especially when fixating - it mixes and almost seems to average together with the scene. i'm going to go home now, see if i can keep this up while walking around outside.

trip home was uneventful, just uncomfortable. i was wondering if i'd get sick on the train, but nothing like that; instead, the constricted visual field, and noisy monocularity of the remaining field, made everything seem closed in, like the whole world was crammed into my face. not sure i can chalk that up to loss of depth perception, but it was in a way a much smaller, flatter world. claustrophobic.

when i got home, i took off the eyepatch while looking at jingping, to see if she'd notice anything odd. for the first second or so, i couldn't fuse the scene, but then it came together. still, there was an uneasy feeling that i was going to lose fusion, and i even tried to provoke it, but everything stayed together. the contrast aftereffect was surprisingly minor; the luminance aftereffect (it was dark under the patch) was more sustained.

Thursday, November 07, 2013

vision and light


top 10 total disconnects between light and vision

1. symmetric encoding of more versus less flux. actually, more neural response to darkness than brightness. neural silence is encoded as a neutral gray. so, a domain of natural numbers, i.e. numbers of photons, is mapped to a U-shaped function of neural response. no, not even a U-shaped function. see Whittle.

2. nonsensical encoding of the EM spectrum. the visible spectrum, continuous linear change in photon energy, wrapped around in a circle? red next to blue? clearly no idea.

3. color constancy and the Adelson illusion.

4. mach bands and phosphenes don't count. these are reasonable side-effects of having a system processing things. you can see the corners of the system, or you can bump it around. no harm here.

i am taking suggestions:::

Wednesday, October 23, 2013

no labels

updates:

1.
basically finished a new paper, a few ideas in there that i'm not sure are properly defined, but hoping my coauthor or some reviewers can help get things in line. hoping i can submit it somewhere within a few weeks; if so, will be the fastest turnover from study inception to publication that i've achieved yet (started this work last December).

2.
supposed to give an institute lecture next week, not really prepared. going to ramble about philosophy of mind, psychophysics, and visual illusions. i hope i don't come off like a crackpot. i am not a crackpot!

3.
last few days, keep getting confusing afterimages; look one place, then another, and think i'm seeing the previous image (usually a fine texture or detail) in the current location. has happened maybe ten times in the last 48 hours. this morning, for example, standing in the hallway at home, looking into the living room; i briefly foveate the 'foot' of our coffeetable, which is carved with an intricate little design; then i look somewhere else, can't remember where, and i'm still seeing the foot design. lasted just a few hundred milliseconds. later, waiting for the train, i look at the station clock, which is made up of an array of yellow-green LEDs, then somewhere else, and see the pinpoint-grid in the new location. i don't think that in either of these cases the afterimage was stronger than usual in a SNR sense, but it was somehow noticeable or salient where it should have been ignored. it's a type of confusion, rather than over-representation.

Monday, October 14, 2013

objectivity

I finished Chalmers' book - The Conscious Mind - this weekend. A funny thing was that the next-to-last chapter, basically just a set of musings on the relationship between his proto-theory and artificial intelligence arguments, didn't interest me at all. This is funny because if this was 2001, I probably would have skimmed the book up to that chapter and then read it over and over and over again.

It's an excellent, important book. I wish I'd read it back when, but now was good enough timing. As I mentioned in a previous entry, just about all of my thinking on philosophy of mind and consciousness in this book; I think some of the ideas I developed naturally, like a lot of people do, but I've also read many of Chalmers' papers over the years, and a couple I've read many times, so he's undoubtedly responsible for straightening my thoughts on the subject.

But this book, it's one of those cases where reading is like sharpening your mind. You may have a set of knives, but you've let them clatter around in a drawer for a while, used one here and another there, and so they get banged up and dulled and maybe a bit tarnished, and so finally you sit down with the whetstone and a cloth and sharpen and clean, and there, a drawer full of shining, sharp knives. That's what it was like, reading this book.

In a way, it just sort of set me up with new vocabulary, or ways to structure my thinking about perception and experience, and why they are interesting, and what the alternatives are in thinking about how they are interesting. Sometimes, this is enough to take away from a book - it helps you organize, doesn't revolutionize your thought, but it helps you straighten things out, like putting the knives into categories, with the tips and blades all facing together.

But he also inspired me, and hopefully just at the right time (though I was asking for it, looking for it, so it's silly to bring up the notion of coincidence). He talks about psychophysics - although in more basic terms than the conventional science - and he presents it as a way of using subjective experience as evidence, as a thing to be explained. This was how I felt about it for a long time, but as the years and papers and experiments wheel on, you can't help but start to see things operationally, in terms of functions and moving parts, and you operationalize your subjects too, and they become black boxes that press buttons. This is so wrong!

It's wrong, and I used to know it was wrong, and I've maintained a sense that it's wrong - I recognize that this sense is part of what sets me against the West Coast internal noise crowd in modern psychophysics, and which allies me so much to the European tradition. But I'd kind of forgotten, explicitly, how it's something of a travesty against psychophysics to operationalize your subjects, especially if you're interested in psychophysics per se, and not in using it as a means to another worthy end.

What I'm rambling about is what we all know - when you have a subject in a psychophysics experiment, and you give them instructions on how to do the task, you are asking them to take hold of a phenomenal object, and to give you responses based on that object. Often the object is so ineffable that it can only be explained by example - 'this, you see this? when you see this, press this button; or, press this button when you think you see this, here'. The central object in the entire experiment is the thing that is seen. The instructions to the subject are the closest that the experimenter comes to the phenomenon of interest. But it's too easy, I see now, to slip into the mode of giving those instructions and then thinking that the phenomenon is in the data, and that by describing the data or understanding the data, you're understanding the phenomenon.

Ultimately, maybe, it's just semantics. Ultimately, all you have to analyze in any rigorous sense is the data. But I think that many psychophysicists forget, and start talking only about performance - I've done this many times now. I've gone long enough without enough inspiration, for years now, only seeing it peek through now and then, always having trouble circling back to the real object of fascination. But this book, Chalmers' book - or probably, just a few choice passages from the book - has renewed my clarity, and as I said, just in time, because I feel that the importance of these ideas, for my research and my writing and my very career, is swinging right into center stage.

Also, I have a headache right now, officially it's been 59 days since the last, longest gap since record keeping began (May 2012). I gave it a 3.5, but I'm going to go raise that to a 4.5 now, it's getting worse.

Tuesday, September 03, 2013

false features in text

spent the morning reading papers. there was an interesting exchange in JOV about what was probably my favorite paper of last year; the exchange strengthened my opinion of the paper, but i'm not going to go into it now, because this post is irrelevant to the actual substance of the articles in question.

here's what i saw/see (in the letter-to-editor attacking the paper in question, as displayed in my browser):

[if you want to see it, keep fixating this line, but attend to the lower part of the text below].


Do you see it? I need to ask around. I notice these things a lot, but they're never as salient as this. In case you don't see it, here's an illustration:


There you go. Go back to the first one and see if you don't see that arc. I only see it peripherally (had to draw that line in without looking at it), but scale isn't so important, and neither is field location (so long as it isn't central). The left eye sees it better than the right, and it's stronger overall with both eyes. To me, it's so salient as to be distracting. I had to do all these tests to convince myself it wasn't a retinal tear or something.

(also interestingly ironic is that the paper(s) in question are all about measuring threshold-versus-noise functions, which are shaped just like the illusory/actual line.)

It's apparently just accidental peripheral concatenation of the structure of the letters and words in the paragraph - crowding, basically - but really, if you look straight at the texture, it's damned hard to see just what is stimulating this process, and why it isn't happening everywhere. But it's neat - basically, a positive effect of crowding or lateral interaction, which is usually held up for its negative (destructive) effects.

Also, I think this qualifies as a deja trompé. Haven't had one of those in a while.

Tuesday, August 27, 2013

special blue light

something i forgot to mention in the Montreal post:

standing on the balcony outside AR's apartment, you can watch the alley four floors down. across the alley is what looks like an old office building - occupied, i mean, just old. it's nighttime, dark with moonlight and streetlights. the lights are mostly out in the building across the alley.

on the ground floor, through a window, seemingly under a desk, you can see a faint blue glow. it seems to come and go, but in fact it's constant. it's a blue LED at the front of a computer tower, or some other device. it's just dim enough that if you foveate it, you see blackness, but if you look away just a degree or more, it pops into view.

it's easy to see this effect with stars at night, or with any dim detail when you're dark adapted. and we all know that the fovea is free of blue cones, though i think this light was not so blue that it wouldn't be stimulating green cones, if they were sensitive enough. the trick is that they were not sensitive enough, but the periphery was. but the answer can't be that it was rods mediating the peripheral seeing, partly because the color sensation was plain, and partly because we were going in and out of the apartment, there were other lights all round, so the rods shouldn't have been especially useful.

so the explanation must be the blue cones and the insensitivity of the green cones. the light was dim enough to be invisible to green cones, which if it were brighter would probably  be stimulated (though maybe it was blue and pure enough that this latter point isn't even true; however, a quick google suggests that standard blue LEDs have peak spectral power at around 540nm, which is within the M-cone tuning width).

anyways, i thought this was interesting. it took me a couple of minutes to convince my companions that the blue light wasn't actually slowly flashing on and off, that it was all in their behavior. that was the best part.

Sunday, August 25, 2013

TMS

went up to montreal for the weekend, on account of jp's inter-rotation break. had a mostly good weekend, won't go into the problems here.

relevant part to this journal: i had my first TMS. my friend tk has been working on some TMS experiments alongside her boyfriend, ar. ar is french. so one point of interest for the weekend was spending a night and some time in the apartment of a frenchman in montreal, which i'd never done before. small things matter.

anyways, even though they were resistant owing to my falling on their official list of 'do not tests' (migraine), i managed to push my way into the TMS room and got a few zaps. jp too. they had it set at low power, don't remember the numbers. they started at parietal cortex and got arm and hand muscles to twitch, though i could never really feel it through the much more salient face twitching (which i think was just caused by conduction through facial nerves, not cortex). both me and jp got the arm/hand twitches. i didn't think it was that interesting really. maybe higher power and finer tuning would produce a more interesting result.

then they tried occipital cortex. jp couldn't see the phosophenes, but thought maybe she might see something. what i saw was very clear. exactly synchronous with the click, against the darkness of occluded and closed eyes, below and just right of fixation (which happens to be the locus of most of my migraine auras, though i didn't mention that), i saw a patch, maybe half a degree across and of irregular but defined shape, with a boundary shaped like poland or ohio. it seemed to be a brightening of the background noise, almost had a golden hue against the red-black background; as it flicked off, i thought it left a fine-grained afterimage, redder, maybe with striations.

so that was interesting. less amazing than i expected, but he was keeping the power low so as not to induce a seizure. i've read up on it, and there's no actual evidence that migraineurs are susceptible to seizure from TMS. i told him i figured it was like having everyone turn off their e-book readers on the airplane at takeoff. no evidence of trouble, but it is the brain (or an airplane), so may as well be safe.

got a sunburn biking across montreal. saw the buckysphere. i have a mustache.  what else... well, many things. by the end of this week, i must have applications prepared. must or bust.

Tuesday, August 20, 2013

update

no thoughts to essayize lately, at least none which aren't going into manuscripts. productive summer of writing so far, will have produced at least 4 papers of my own this summer and lots of stubs for future work. current paper is unfolding in an interesting way; collecting a little more data, should have it all done in another week or so.

going to montreal this weekend.

decision on postdoc i applied for won't come til octoberish. preparing faculty applications in the meantime.

migraine news: last friday night developed a fine, sharp, right-side headache, on the trainride home from seeing Pacific Rim - best movie i've seen in a movie theater *maybe ever* - came home, went to bed, couldn't sleep til 2am because of the pain.

interesting thing was, when i closed my eyes, i could see, faintly, these very, very fine striations, like looking at my thumbprints from 50cm distant; 20+ cpd. they would follow one direction and fade into the black/redness of the eyelight; then i would see the other orientation, and they would fade, and so on. they kind of had the appearance of the extreme eye movement striations, but finer. maybe they were from irritation of the optic nerve? i couldn't tell if they were in one eye or the other, only noticeable when both eyes were closed.

Monday, July 29, 2013

seeing spots

phosphenes aplenty these past few days, and a headache since saturday (mid-monday now), but no aura. i'll spend this post describing the phosphenes, which are interesting.

the phosphenes are always exactly foveal, less than a degree across. they are never noticeable for more than a few tens of seconds. the sensation is very similar to the very beginning of the typical aura. their appearance is very subtle, as though there is a smudge over the central view. it's comparable to having looked at the sun glinting off a surface and having a bright foveal afterimage. sometimes it seems that i can close my eyes and see a floating spot, like an afterimage, which easily fades from view; sometimes i can't see anything.

another sensation that the phosphene is similar to is lustre or shimmering as from interocular conflict. earlier today i found myself gazing into the distance above my desk, thinking about something, and thought i was seeing a spot; then after a few seconds i realized that my left eye was seeing a mark on the underside of a plywood shelf, where a screw pokes out, with my left eye, while the same view by the right eye was occluded by a hanging piece of paper. once i understood what i was seeing, the sensation seemed to change; it is as though i am strongly sensitized to the onset of the aura, and when i think i am seeing it, or seeing these blippy phosphenes, i feel that i know i'm seeing it, which turns back around and affects the way it feels to see it.

a third way of describing the sensation is as scotoma-like, but there is never any scotoma, or at least not any so large or stable that i can see it. it's more like what is seen is interfered with; maybe it's a scotoma in the confluence? mostly in V2/V3?

anyways, the foveal spots are always brief. in the past few days i've noticed them a dozen times. during the same period, i've repeatedly noticed the familiar difficulty with reading text, especially in the morning. i look at black text on a white background, and it's very difficult to read, as though the letters are jumbled. i think what's happening is that the afterimages aren't being properly suppressed, and that it's only noticeable with the high-contrast stimulus of black-on-white text, especially on a computer screen where the white is really bright. at other times i've noticed problems with afterimages, especially of textures, seeming to 'stick' from fixation to fixation, thinking that i see something in one location when it's actually carried over from the previous fixation. these sensations aren't afterimages in the common sense of light impressed in the retinas, which have their characteristic slow fuzzy fade; they are clearer and sharper at the same time that they are less substantial.

a headache started saturday sometime, then disappeared, then reappeared yesterday, subtle - only noticed it when changing posture - and remains today, where it was slightly excruciating earlier and mostly gone now. right trigeminal nerve, felt it above the right eye at the supraorbital nerve, and above my upper right teeth.

Friday, July 19, 2013

cat vision

Sharpness is, really, an illusion. It doesn't represent anything about the world, it's just an indication that the limits of resolution of the visual system have been met. In that sense, it's relative. I've thought about sharpness a lot, starting in graduate school, when I first wondered whether, having learned the quantitative difference in visual spatial resolution between cat and human, a cat could see stars. My first thought was no - stars are so small, if blurred they can't be seen; then I recognized that human acuity is nothing special (a sort of Copernican principle for vision), and that sure, cats should be able to see stars just as humans can. But they would look different, wouldn't they? Blurrier? No. To see blur implies you have the acuity to see what is missing. So then, they would look larger? No, for the same reason - if a star appears as a disk, that implies its edges are seen separately, which implies acuity to separate them. So to a cat, whose acuity is almost an order of magnitude worse than a human, stars must also appear as points. How to make sense of this?

This gets at a more general sort of paradox about visual resolution. Lower acuity isn't the same as blur, not at all. Acuity is an ability or a capacity; blur is a state or an affordance. A certain acuity enables you to see a certain amount of blur - that is the relationship. But we easily confuse the two by trying to represent the effects of acuity as blur. This is a common demonstration: illustrate the spatial resolution of the visual field as round window with a focused center and increasing blur towards its boundaries. This kind of demonstration is useful in that it shows what is lost in peripheral vision (in terms only of 1st-order resolution) relative to central vision. But it is harmful in that it conflates blur with this relative difference in visibility. Because really, no matter what the resolution is, there is finer content that cannot be seen.  We can think of this kind of demonstration, of comparing resolution at different visual field locations in terms of blur, an 'isometric' demonstration, since space is kept constant or symmetric over the whole field, though apparent sharpness falsely appears to change. This demonstration doesn't violate our intuitions about space - space seems, and is, symmetric to translations across the visual field - though it does fool us regarding blur.

Another way of demonstrating the same variation in resolution across the visual field is to reverse this relationship; that is, with an isoambylic representation of the field. This representation would have equal sharpness everywhere, but would vary metrically across the field, giving something like a fish-eye lens view of the scene. For some reason, even though the isoambylic representation is just as 'fair' as the isometric, its distortions are more disturbing. Maybe it's because the spatial asymmetry is unfamiliar, whereas blur asymmetries are more familiar.

So now we go back to cat vision. Imagine that you and a talking, scientifically interested cat, are discussing the topic at hand, and wondering how to explain to one another the differences in your spatial acuity. I think it's time for a dialogue!

Tacitus: So, here we are.
Otho: True.
Tacitus: We're supposed to demonstrate to one another the differences in our visual fields, in terms of spatial acuity. How do you think we might do that?
Otho: Well, for starters, let's use pictures.
Tacitus: That's kind of a given.
Otho: Good. Here are two copies of a scene. The one on the left represents your acuity: you see that in the center, the image is sharper, and it gets blurrier as you go out towards the edges.
Tacitus: I do see that. Nice and sharp in the center, blurrier toward the edges.
Otho: If you stand right here, and look at the center of the picture, you shouldn't be able to tell that there's any blur, because the blur is matched to your acuity. What do you see?
Tacitus: It's just as you say. Interesting!
Otho: Good. Now, this picture, on the right, represents my acuity. It's similar in that in its center, it's sharper, getting blurrier towards the edges.
Tacitus: I see that, but...
Otho: But what?
Tacitus: But it looks just like my picture. I can't see a difference. Maybe.. it's not quite as strong a trend, from the center outward, but I can barely tell.
Otho: Well, the difference is obvious to me. It's because my acuity is so much better than yours, all around.
Tacitus: Well, then this isn't fair. Why can you see so clearly the difference between our visual fields, while I can't see it at all? I feel left out.
Otho: Hm.
Tacitus: Here, let's try this. Instead of using blur to represent acuity, let's change the size of the images. We'll transform the images so that the acuity limit, which is just a measure of distance within the visual field, will be a fixed distance.
Otho: So that means that when acuity is high, the image will be relatively magnified, since you're taking a small distance in the visual field and stretching it to, let's say, one centimeter. And when acuity is low, the image will be compressed, since you're taking a big distance in the field and squeezing it into that same centimeter.
Tacitus: Exactly!
Otho: The images will look funny, though.
Tacitus: Well, the funny-ness will be our explanatory tool. We should both be able to notice changes in size, right? I can see a spot a centimeter across from this distance, and so can you.
Otho: It does seem fair.
Tacitus: Okay, here we go.
Otho: Wow! My visual field is so big! And look at the distortion, it's like a fish-eye lens! Why is your field so small?
Tacitus: Didn't you just explain it to me?
Otho: I know, I was just surprised.
Tacitus: And mine also looks like a fish-eye lens, just a bit less extreme. Yours is interesting, I can see so many details there that I can't see in mine. I didn't realize you could see such small things!
Otho: I'm sure you did, you just haven't realized it in a visual sense.
Tacitus: Well here it is.
Otho: Can I go back to bed now? It's 3am.
Tacitus: Go ahead and try. We'll see how it goes.

Saturday, June 29, 2013

toronto

just in time to make it 2 for June:



Notes at the Robards Library on the U.Toronto campus, 3:30 pm on 6-26-13.

My feet are very tired. Got up this morning at 5, took a shower, kissed my wife goodbye, and went out to meet the waiting taxi. Had a coffee at the airport.

Got on the prop plane to Toronto at 6:30. Had a coffee on the plane, with a muffin and a cup of yogurt. Clearly I am thinking of food.

Looking out the plane window while we were still on the Boston tarmac, I noticed that I could see the flicker of sunlight through the propellers - I was sitting right next to the front of the left engine, on a plane that was two thirds empty - but only in my periphery. So the propellers were rotating no faster than 60 Hz. Once we went to take off and the engines revved up, I couldn't see the flicker anymore - revving up meaning revving faster, you see.

Got to Toronto by 9, the Billy Bishop airport, on a little island on the lake in front of the city. First person off the plane, last through customs. Canadian customs are actually pretty challenging! Dunno what was up with that.

Then, took a 1 minute ferry ride to the shore, and walked north on Bathurst street. Made it to Kensington market and found a little open air restaurant to get breakfast. It was almost 10. I was already soaked with sweat. Ninety degrees out, humid, and not a cloud in the sky, and I'm wandering the streets of a strange city with a 10 pound bag on my back and a poster tube on my arm. I had a cheese omelet, which came with salad and hashbrowns, it was pretty good. And toast.

I am so hungry. I then wandered for about an hour, through Toronto Chinatown, until I came to the Toronto Art Gallery or whatever it's called. Bought a ticket and discarded my luggage, and wandered the museum for 3 hours. Best part by far was the set of installations on the fourth floor, something I've never seen before: little repeating 3-d audiovisual pieces, rooms full of stuff with recordings playing - some of the recordings were little dramas, one was just a rainstorm, from start to finish. It was great. Had a coffee at the museum.

Then I left the museum and went the wrong way, south instead of north, deeper into the city instead of towards the University of Toronto. Finally I made it here, and now I'm resting in the library, cooling off and writing these notes. I took lots of little videos of my day so far.

From here, I need to 1) get something to eat, 2) get to a subway station, 3) figure out how to use the Toronto subway, and 4) use it to get to York, or as close as I can (then I have to take a bus, apparently). If all goes well I'll be at York University in no less than 90 minutes. Wish me luck! I'm so hungry.

part 2, 18:56pm, June 28 2013

Meeting is over. Sitting in the weird weird weird Billy Bishop Airport departure area/lounge. It would be much nicer if half the flights weren't delayed because of some storm.

Meeting was interesting. Had several talks with F.K., about my current in-review JOV paper, for which he is one of the reviewers; about my current little blur adapt project that I presented (to 3 people, I think) here at this meeting, he had some very helpful comments there; and on other random spatial vision lightness brightness topics. Lots of fun, I think talking to him made the whole meeting worthwhile.

Also met with D.G., as a sort of pre-interview for a postdoc position. Not sure I want to really apply. I was testing to see if it was something that might be up my alley, definitely far up it, but now I'm thinking maybe too far. It's probably too much of a stretch to try to work natural scenes and spatial vision into the level he's working at. I'll study his work over the next couple of weeks, then let him know.

Also managed lunch with F.W. to discuss migraine psychophysics. She seems to have cooled a bit on the migraine spatial vision business, but is still interested. Similar attitude to N.H. about the difficulty and unlikelihood of having migraineurs do vision tasks or perimetry during their auras, though I am not convinced. I will take the long view. M.D. is enthusiastic, I met with him last week. I am almost thinking of writing an entire proposal out, it seems it would be relatively straightforward. I feel I've put all the requisite pieces together, i.e. bounced ideas off all the important people. The main thing that's missing is predictions as to how certain psychophysical properties might be influenced, which is something that L.L. brought up on his own. So now, it seems I should get back to him.

Interesting things I saw... C.B.'s keynote address was pretty bad. I don't know what the general opinion was, but it seemed for the wrong audience - like he was addressing a bunch of visual physiologists in 1992. Don't know what was going on there. Good talks were R.K. on superior colliculus, showing us maps and explaining function, things that if I've ever learned them I've forgotten; G.L.'s talk was interesting, reading and training reading with CFL patients; H.W.'s talk was good, R.B.'s I thought was too much review; A.P.'s talk on form perception and V4 was very interesting. A.P.'s and R.K.'s were like little topical seminars on things I didn't know; I guess R.B.'s was similar but I already knew all of it. D.Z. gave a talk on how MRI magnets affect the fluid in the semicircular canals, resulting in constant nystagmus for anyone who gets into an MRI machine. I remember the slight shock I got the one time I was put in an MRI magnet, but I don't remember noticing nystagmus. I might have thought it was concentration problems, instead.

So that was the meeting. Mostly good, a little slow in some places. I got to attend the retirement of the great H.W.. Poster sessions were too brief, barely worth the trouble, though I did get F.K.'s comments and H.W. came by and didn't complain about anything, though he didn't volunteer compliments or suggestions either. He thought the phase filter was a neat idea, though.

***

Observations on Canada

The way of speech is different. They do say 'soarry' instead of 'sarry', and they say it a lot. I hear a lot of 'os' instead of 'as', 'possengers' instead of 'passengers'. There's something else, a character that feels narrow somehow. I don't know what 'narrow' means there, but it feels right, so I'm using a word that feels right to describe a feeling that I can't otherwise describe. May all be in my head.

The York campus, which is in the northern Toronto suburbs, had lots of animals. I saw a raccoon, a groundhog, and a rabbit, and lots of black squirrels. I saw the groundhog and the rabbit at the same time. I don't think I've seen a raccoon up close since I was a kid, probably out at the cabin or something. And I'm not sure I've ever seen a groundhog up close. This was all right in the middle of campus.

When I was trying to get up to York, just having gone into the Spadina station, I got turned around and lost and couldn't find my way. An older guy, long white hair bound up behind his head, heavy set, white beard, noticed that I looked confused, stopped, and told me where to go.

Again, I feel that the people are different. A part of it must be in the speech, which sounds American but is subtly different. I think a professional would be necessary to explain the differences completely. Multiple idioms that I've heard from C* and D*, many times up here. I wish I could explain the feeling better, because I don't think it's all language. Maybe more visits will resolve this place better for me. It may be because this is big Toronto City, but people seem to dress strangely, less conservatively than Americans in general. Gaudiness isn't standard but seems more common than on Boston streets, at least. I guess I can't generalize from Toronto to Canada. Toronto is clearly an immigrant city, I would say barely half the people I saw in the city were white, lots of Chinese, black, brown, etc. In that sense, it reminds me more of San Francisco or LA. It's very unlike Montreal, which did not have such an American appearance, and which at the same time was much more white.

Aside from the people, it looks exactly American. No obvious differences in infrastructure. The York campus has lots of tunnels and connected buildings, which I would guess is more due to the winter cold and snow and not some sort of Canadian preference for warrens. When I walked through the city I got feelings of China-ness somehow, I think because there was so much construction going on. Nothing about watching the streets makes it look different in any obvious way from watching American streets.

All flights are delayed by hours. Some are nearly canceled. I don't know what's going on, must have been a string of storms across the northeast.

First time ever, I saw another Tennesseean at a vision meeting. He was an undergraduate from MTSU of all places, said he was from Bellevue. I questioned him a bit and he just talked and talked. Despite being from Bellevue, he seemed not to have heard of Cheatham County or Kingston Springs, and so I didn't like him. Complained of Tennessee as a place to escape, where no one wants to return. How can you want to escape if you don't even know your surroundings? Not that I'm not ambivalent about this myself, and I'm half over as old as this guy, but I don't think I was ever that bad. Main thing that rubbed me wrong was that he talked too much, which I guess is just a personality trait. It will probably get him places, I don't know.

Back to Canada. The buses were just like American buses. The subways were regular subways, long cars like the China style, where you could walk from end to end. Spadina station where I first got on was a link between two lines, one of which I didn't travel on, but it looked a lot like the Boston green line, trolly cars running through tunnels. I would have liked to try that one. The friendly white-haired guy got off one of those.

Forgot to mention til now, had a headache yesterday morning, give it a 7, maybe even 8. Woke up with it and it got worse through the morning, coming and going. Quasi-hangover, but I'd just had 3 beers with a full dinner the night before, not enough for a real hangover, though I think the alcohol probably did cause it, in addition to dehydration from the long trek across the city and the general relief of arrival. Slept terribly Wednesday night, partly from the headache starting, and partly from Terry calling and texting me every 10 minutes starting around 6am, probably had barely 5 hours total.

Right eye trigeminal was sore, still sore today, but the headache disappeared over lunch yesterday, went from a 7 to nearly zero. I was still a bit dazed and confused, but got over it pretty quickly. Slept well last night, got at least 8 hours in, maybe more.

Wednesday, June 12, 2013

accidental maxwellian view?

Busy this month, and keeping it to myself so far.

The title of this post is just a guess. Let's talk about some interesting entoptic (or maybe just optic) phenomena.

First is something that I've noticed before, in the same context that I'm going to describe here, but also during our winter trip to China in late 2011, lying in bed one morning and watch the sunrise through the curtains, with my eyes full of sleep.

I'm standing at Fenway Station, waiting for the train to come and take me home. I'm soaking wet because its pouring rain and I didn't take an umbrella. My glasses are specked with water droplets. The sun has set.

I find that I can attend to the fine structure of the images projected on my retina (I'm doing this one eye at a time) through the water droplets. This is a little strange, since the droplets are just a couple of centimeters in front of my eyes, so it should be impossible for me to focus on them and to resolve such fine details, but I'm doing it anyways.

The droplet images - for the most part circular, disk-shaped - look like something between an amoeba and an image of the sun. The amoeba-ness is from their speckled, squirmy, internal structure, like a bag of little bits and pieces. The details are fine, near my acuity limit. The sun-ness is from their perimeter, which has a rim that stretches outward, like the corona of the sun in eclipse. I will draw a picture and put it here, since I can't find anything like it on the internet.

These things I've noticed before. My theory is that the droplets are acting as little lenses, focusing an image near my pupil, which is then - in a sort of accidental Maxwellian view - getting perfectly focused on my retina. The structure I'm seeing is the texture of the interface between the water and the surface of my glasses, little bits of dust and et cetera. It's like seeing a water droplet through a microscope, which adds (through psychological association perhaps) to the impression of seeing an organism. The rim is the edge of the droplet, the meniscus, and the corona is the stretching of the edge due to surface tension.

All that is just a guess! Nobody I talk to seems to have a good explanation, but that seems as good as any.

The next part I had not seen before.

I found that in my left eye, but not in my right, when I blinked, I saw bright specks, pin points of light, against the background of the droplets. I couldn't see the specks outside of the droplets.

When I attended more closely, I discovered extremely fine structure to the points of light. Basically, they looked like this:

I tried a sinc function, but that wasn't quite right, because I couldn't see more than a couple of rings, like you see here. What you see here is the product of a radial sin function, with the center set to 1, and a radial Gaussian. In words, each pin point was surrounded by a black ring, which was surrounded by another bright ring, then a dim ring, and then I'm not sure. Each little point was the same as the others, but I had to get them near the fovea to see them clearly. They were tiny; they each were only a few arcmin across. And, they were bright: the central point was white, and the ring surrounding it was black.

I really don't know what these things were. I have forgotten a crucial detail: did they move when my eye moved? I feel that I could look from one to the other, but I don't remember if this is really how it was, or if it's just how it seemed. If that's how it was, they can't have been on the surface of the eye, and it's hard to explain why I only saw them in the left. At the time, it made sense to me that they were on my cornea, specks of dust, so I think they must have been fixed to my point of view. They slowly faded and became less distinct, and I would occasionally blink to restore them.

So, weirdness at Fenway.