Remedial Polymath

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It’s really quite astonishing and perplexing, while also being something that we can be told and quickly reflect, “yeah that makes sense, our eyes can’t be 100% perfectly”, and then move on. But seriously, it’s completely wild. Actually, it could be considered more than that, it’s somewhat unnerving.

In this episode we will explore vision. Because when one looks a little bit into it, what we do and don’t know about this sense of ours, the information and its implications are simultaneously disquieting and exhilarating. The correct words here are difficult to find, but hopefully by the end of this you’ll agree with the sentiment here.

You think you see the world around you? Think again, you basically hallucinate the world around you, in some ways it could be said you imagine it. Not only that, but even what you “hallucinate” around you is filtered and processed in many ways. Your brain, without your input, presents to your “consciousness” what it thinks you should know about your visual surroundings, which is not a true reflection of said surroundings. The word consciousness will be used here as the closest word to explain what one experiences concerning your interaction with your vision, not what the brain and eyes are doing all on their own without our input. Because our brains really do seem to act more like a giant filter than anything else.

One hopes that intrigues you enough to learn more. Let’s jump in.

Us humans have two, pretty decent for the animal kingdom, forward facing eyes. Evolution has put millions of years of research, trials and errors, and investment into crafting the visual sense organs we posses today. It is unquestionably our most consequential and leaned upon sense. It informs us about most everything related to where we literally are in the 3 dimensional world around us, gets us to where we want to go, alerts us of danger, and gives us senses of wonder and beauty – from just casting our gaze at other humans, nature, artwork, or in other visual treats like beautiful buildings or exciting movies. It not only has an inherent value in that it’s constantly informing us how to operate in our world – and importantly, how to avoid dangers – but we also place great value in it’s experience, so much so that certain colors arranged in certain ways on a canvas can be considered quite literally “priceless”. Colors, on a canvas, placed in a certain way (and they don’t even have to make sense, just ask Jackson Pollock) that provide no other purpose than to entertain our eyes are literally considered so valuable that they can transcend the idea of even having a value. I wouldn’t argue with that fact, but if you step back it is also a bit crazy. Not even the most popular songs of all time, even if you have the original recording, are valued in the same way as visual art.

It sounds corny, maybe because it is, but just as we call other people’s eyes the “window into their soul”, they are also our own window into the external world. Vision is the most important sense as relates to our experiencing life, so much so that about a third of the entire cerebral cortex is dedicated to vision. Some scientists even say it’s could be more, it’s hard to know exactly (more on that later). But we know it’s a lot. The cerebral cortex is the part of our brain that plays a key role in memory, thinking, learning, reasoning, problem-solving, emotions, consciousness and functions related to your senses. Without the cerebral cortex we wouldn’t know ourselves as human, and a third or more of it is dedicated to looking around and understanding our surroundings.

So, we really should maybe explore what we know about this vision thing, seeing as how important it is. Because, as we will explore, if it’s not a perfect representation of our surroundings what does that say about our understanding of our own life experience? Don’t be discouraged by that thought, it’s really could be understood more as a type of continuous magic than anything else.

I don’t have to know you to be certain that if you have vision, you usually treat it like it’s an accurate reflection of your environment. It would be quite odd not to. And for most people (but not all), there is no reason to act in any other manner because it has not let you down.

Let’s start with some everyday basics about how much seeing you actually do with your eyes. Let’s start with a couple, admittedly pedantic, observations that may just crack open the door to challenging preconceived notions. We all have the experience of dreaming (and for those one in a million people who say they don’t, you do, you just don’t remember them and that is a condition truly worthy of pity). In dreams we somehow dive into realms of our own sleeping mind and see things – on a daily, or rather nightly, basis – that aren’t there at all. Not only that, we often then see things that we have never, and would never, see in our waking life. Things we have no experienced based reference for. And while this is happening your eyes are telling your brain that you are seeing pitch black. How weird, how magnificent.

Somehow, we brush off those spectacular vision experiences and their mysteries. “They are just dreams, get over it,” one can hear others saying in response. That’s understandable, but can we not also just stop and ponder for a moment what it means that we experience sight even though we may have our eyes closed, in a dark room, with an eye mask on, while our body is essentially paralyzed and we are almost cut off from the outside world? What is sight if we don’t need eyes to experience it? Have you ever stopped to wonder why many people associate vision solely with their eyes even though a third of their lives are spent sleeping and experiencing vision without them?

Moving on, while in dreams we see things that aren’t there, what about not seeing things that are there? We’ve all had that experience. It’s not as cool of an observation as dreaming, one can admit that, but we all do it. Want proof of this? Do you normally see your own nose? What if you close one eye? It’s normally not there, but then – voila – there it is. What is making this decision to not normally see something so clearly within our field of vision, and why? And what is replacing that part of our vision that should be our nose? This almost childish observation is a hint to us that our brains really do make a lot of visual decisions for us. It can override the eyes.

Then, of course, there is the well known fact that we can induce hallucinations, which not all have experienced but should be aware of. Whether that be through chemical means, via some sort of hypnosis or psycho therapeutic state, or through an unfortunate state such as schizophrenia. In your waking state, as well as dreaming, it is quite possible to flat out see things that aren’t there.

Yes, simple and arguably mundane observations. Yet maybe they are easily accessible observations that may open some up to the wizardry of sight.

Let’s now examine what we do see the vast majority of the time, light. Or more precisely, visible light.

We only pick up a minuscule sliver of the expansive range of different types of energy that resides on what is known as the electromagnetic spectrum. On this spectrum exists energy of many different wavelengths or what’s know as photon energy. The longer the wavelength the less energetic it is, the shorter the more energetic it is. The wavelengths stretch from the the size of a nucleus of an atom to thousand of kilometers long. You’ve probably heard of the other types of electromagnetic energies, maybe without realizing that visible light falls within this spectrum. A couple of the shortest wavelength energies are gamma rays and x-rays, which are so energetic that they can actually be quite harmful to living material. Then there’s infrared, visible, and ultraviolet light. After which follows other types of energy such as microwaves and radio waves, the very same that heat your food and entertain your ears during the morning commute.

The wavelengths for visible light are roughly between 400 and 700 nanometers long, with a nanometer being one billionth of a meter long. Electromagnetic wavelengths therefore can be fractions of a nanometer long for a gamma ray to thousands of kilometers long for the weakest radio waves. So when we say that light occupies a sliver of the spectrum, it’s more like a sliver, of a sliver, of a sliver.

Why is it that our minds have decided to leave out so much information and focus on such a tiny band of information? Sure, maybe more information wouldn’t be useful, if we saw radio waves we might end up seeing nothing else, but maybe it would, a little infrared could come in mighty handy in the dark (see: night vision goggles). In fact, many other animals do see other parts of the electromagnetic spectrum.

Either way it’s clear that we’re not seeing the whole story when we open our eyes, it’s basically akin to just seeing a sentence or two of War And Peace. Yet our brains have figured out, or maybe even gambled upon the fact, that this is the most useful part to use. In fact the sun releases most of its energy within the visible light spectrum, which makes sense, as you can see the light from a star much farther than you can feel it’s heat.

Realizing that we only take in a little bit of the potential electromagnetic information available around us via our eyes, and that this information often can be filtered or modified before being presented to our conscious mind can be a revolutionary thing to ponder upon. It can act as an impetus to create wonder – and wonder is pretty much always self-evidently positive for the human experience. Maybe I’m biased, but hey, so is our vision.

Let us now look a little into some of the cool things about vision and maybe fascinate a little at how much our eyes and brain can do, and what the effects are when it can’t do everything.

The first thing to take a look at would just be the basics of how vision for humans works. It may seem dry and boring at first, but after a little comprehension of what we know about this complex system it should start to make you scratch your head (at least it did for me). How do we get a constant three dimensional, vibrantly colorful, perception of the world around us?

One of the best quick little quotes about vision is from Lai-Sang Young, a mathematician at New York University, while speaking with Wired Magazine. “A lot of the things you think you see you’re actually making up, you don’t actually see them.”

How is this possible? Well, part of the reason is due to the fact that our brains devote a serious amount of “computing power” to our vision. William G. Allyn, who is a Professor of Medical Optics has written that, “More than 50 percent of the cortex, the surface of the brain, is devoted to processing visual information,” (he points this out in an article from Rochester University). He even went on to say that, “Understanding how vision works may be a key to understanding how the brain as a whole works.” Well that’s interesting…

What are some of the barriers to understanding how our sight is pulled off? It’s mostly related to the fact that seeing in the high quality way we do is actually extremely difficult to pull off. We all take it for granted that we can drive a car, understand our place – and that of others – in a constantly changing and moving 3 dimensional space, while taking in important cues from other cars, the signs and directions around us, while turning around to argue with 2 kids in the back seat. The processing power to pull off this feat is astounding, and we don’t even realize it, it’s just everyday life. And if you know anything about self driving cars you know that this has been a very difficult thing to master, even with cars that have a multitude of sensors, GPS, radar, cameras, and a multitude of computer chips. The things our eyes, and the mental computing power connected to them, allows us to do is so amazing as to not be fully understood, no matter how mundane it may seem to us all.

That brings us to the next issue, how the hardware actually works. People tend to think about an eye as being something similar to a camera, that we are just taking in some kind of video stream via our eyes. Because we notice that most animals have eyes, and we have had the ability to see since infancy, we are just numb to the incredible feat we are pulling off with our mind and we reduce it to something akin to technology in our lives that does something similar. We would be in error here.

Ok, some basics. Our eyes do indeed act like lenses (no surprise there), in that they take in the visible light that surrounds us and projects it (upside down, mind you), to the back of the eye, which is known as the retina. The retina is then connected to the aforementioned visual cortex that sits in the back of our brain. There are two types of sensory cells in the retina, rods and cones.

Then things get a tad more interesting. The nerves that send information to the brain, the LGN (or lateral geniculate nucleus) is the only pathway through which visual information gets into the brain. What is curious to scientists about this pathway is that there’s – relatively so – just not that many of these nerves and from what we can tell the information they’re sending to the brain just doesn’t seem complex enough to result in the vision we experience. Knowing this one can start to understand why it’s amazing and perplexing to scientists that we get the results that we do. These LGN pathways effectively send a pulse to the brain with information from the photoreceptor cells on our retina, known as rods and cones.

Consider the rods. They send information when they detect a change from dark to light, or vice versa, in their section of the visual field which leans heavily toward our peripheral vision. They are better suited to dim conditions than cones. When taking into account that the total number of rods in the human retina (91 million) far exceeds the number of cones (roughly 4.5 million) it may surprise one to learn that the vast majority of photoreceptor cells are concerned just with information about contrast changes. Wouldn’t you think they’d be sending more information than that, doesn’t that seem like it’s not enough information?!  You would almost think the edges of our vision should be in black and white, yet that isn’t the case.

So one can now understand that while the retina is shown all of the visible light around us (not unlike how glass lens on a camera displays all of the visible light to it’s sensor), it is not actually always sending the entirety of that data back to the brain. Or at least our brain doesn’t relate all that data to our conscious mind. It gets a bit picky, it values certain sections of what it’s being shown in different ways at different times, factoring in the brightness level or if there is a change in contrast somewhere. It might make sense that our rods are more dedicated to our peripheral vision as in low light situations you seem to be able to detect things out of “the corner of your eye” better than whatever you are staring directly at. This adaptation is probably related to survival, so that dangers can’t as easily sneak up on us in low light situations. In fact it is believed that as we were once nocturnal creatures, our ancestors actually gave up some color acuity—that is, sacrificed cones for rods— so as to gain better night vision.

Rods, as we’ve just seen, are used to see under low light, they’re very sensitive but can’t see color. But then there are three types of cones we need to be aware of. The L-receptors, which are sensitive to long wave length light such as the color red. Then there are M-receptors which pick up greens. Then the S-receptors are sensitive to blue colors. And just like the old school red-blue-green cords needed for the back of a tv, you can recreate all the other colors by combining red, blue, green. It is estimated that the human eye can perceive between 2 and 7.5 million different colors just through the combination of these three. That’s kind of bewildering. Could you imagine what could be seen if we had more types of color receptors? Many fish, birds, and reptiles actually have four types of receptors, meaning that, somewhat oddly these lower intelligence animals actually are perceiving their world in a much more vivid way we can’t even imagine. Additionally, it is believed that a small portion of human (it’s thought mostly women), actually do have a fourth receptor. It is a rare condition known as being a tetrachromat. So there may be people you have interacted with that, without knowing it, in their everyday life see colors the majority of us cannot. Oh, to be able to trade places with one of these people, even if just for one day.

Here’s where it gets even odder. Those LGN cells somehow combine the information from our rods and cones and send off to the brain quick little pulses, 1 every millisecond. That may seem like a lot but it’s not, and in fact it confuses scientists as it was assumed that more information had to be being sent to the brain. But essentially what happens is that that LGN cells then connect to hundreds of neurons, which are then connected to hundreds of others. The visual information then gets thrown around the back of our brain, even coming back to where it came from. Again, from the aforementioned Wired article, “The situation is even more complicated than that. Those hundreds of neurons connected to your single neuron? Each of those is receiving signals from hundreds of other neurons. The visual cortex is a swirling play of feedback loop upon feedback loop.“

I imagine many people may be rolling their eyes (excuse the pun) at this point, thinking to themselves that this all sounds most certainly complicated enough to explain vision. But the important thing to understand here is that our brains really aren’t seeing anything, their recreating the image your eyes take in, work with it in within our brain in ways we barely understand and then somehow presents what it thinks we’re seeing to our conscious mind.

Don’t worry if that confused you, it confuses scientists and confused me when trying to then reexplain and simplify it.

Let’s consider some more accessible information that also communicates how it is that our brain does the seeing and not our eyes; our blind spot and point of focus. Each eye has a blind spot, because the optic nerve has to connect to the back of each eye somewhere, where it does connect we just can’t have rods or cones there. There are numerous tricks one can do to perceive their blind spot, including the one above (scroll down to the end of the article to see another impressive one). The important part, however, is that we should have a significant portion of our central field of vision that is blank. But we don’t, through a process called perceptual interpolation our brains essentially “imagine” what it thinks should be there. And while we have a fancy name for this process it is still not well understood.

Our point of focus, on the other hand, also works with the brain in interesting ways. Your point of focus is about the size of your thumbnail at arms length, or about the size of a quarter of the full moon if you gaze up at it. Yet we sense much more of a visual field as being in focus. This is done through our eyes consistently darting around, with our brain taking about four “snapshots” of our visual field per second, which is then processed and presented to our consciousness the impression of having a much larger in focus field of vision.

This information really hammers home the difference between what you experience and see in your conscious experience of life and what your brain is processing all on its own, in mysterious ways, for your enjoyment and survival within life.

Another way of looking at the mystery and power behind our mind’s computing design is again from the aforementioned wired article: “There’s very little connectivity between the retina and the visual cortex. For a visual area roughly one-quarter the size of a full moon, there are only about 10 nerve cells connecting the retina to the visual cortex. These cells make up the LGN, or lateral geniculate nucleus, the only pathway through which visual information travels from the outside world into the brain.” Just for reference, the human hand contains about 100,000 nerve cells, of 20 different kinds, so that you can experience what’s going on through touch. And while what we experience via our hands are obviously very important sensations (they all are of course), it doesn’t nearly mean as much to both your survival and overall understanding of your world and life experience. Without knowing anything about this subject I would venture to say most of us would guess these nerve related numbers to be the other way around. Yet they are not. Are you starting to see part of the mystery here?

Again, from the same article, “This is the great mystery of human vision: Vivid pictures of the world appear before our mind’s eye, yet the brain’s visual system receives very little information from the world itself. Much of what we “see” we conjure in our heads.” In a paper titled Seeing Out Of The Corner Of Your Eye from Flinn Scientific it is also stated well and simply, “The deeper mystery of why we can see so well with such a terrible visual apparatus remains comparatively unfathomed.”

Strong words indeed!

Okay, So let’s review some of the information just discussed. By taking in red, blue, green and contrast information from a 180 degree field of view we then recreate a highly detailed, 3 dimensional internal image of what’s within our surroundings. Our eyes are sending our brain seemingly limited information yet somehow we then conjure up an extremely vibrant, detailed and reliable vision. All the while our brain is adding and subtracting and combining information from our optical nerves to then present this information to our consciousness is the manner it wants to, and then our conscious mind experiences vision. Whew… Let that sink in.

But if you are still not convinced that your brain does the seeing and not your eyes, and want to think about it in simple terms, just remember again that simple observation that when you dream your eyes are looking at blackness but you are having full visual experiences. Sometimes thinking simply is the best way to challenge preconceived notions…

But wait, there’s one more cool thing. Let’s end on maybe the trippiest aspect of our vision and how our brain presents information to our consciousness. This is from Bill Bryan’s book The Body, A Guide For Occupants: “For each visual input, it takes a tiny but perceptible amount of time—about two hundred milliseconds, one-fifth of a second—for the information to travel along the optic nerves and into the brain to be processed and interpreted. One-fifth of a second is not a trivial span of time when a rapid response is required—to step back from an oncoming car, say, or to avoid a blow to the head. To help us deal better with this fractional lag, the brain does a truly extraordinary thing: it continuously forecasts what the world will be like a fifth of a second from now, and that is what it gives us as the present. That means that we never see the world as it is at this very instant, but rather as it will be a fraction of a moment in the future. We spend our whole lives, in other words, living in a world that doesn’t quite exist yet.”

Side note: If you are not convinced of any of this there are optical illusions online so you can try to examine the realities of these observations yourself. BBC future has a good article about this, where they also state something that relates to the overall message here, “Visual, or optical, illusions show us that our minds tend to make assumptions about the world – and what you think you see is often not the truth.”

So, I think if you have hung in there with me until now you should have enough information to weird yourself out and maybe rethink things. Nay, re-see things, about your world, your brain, and the realities of your consciousness. Isn’t it a bit unnervingly magical that on top of everything we have examined that what we see is actual our brains prediction about what we should see slightly in the future? And it does this through mysterious means that don’t yet make sense to the brightest scientists. But we do understand that what we see is related to the information that enters our eyes but is not reliant upon it. And remember, it does so through the part of our brain that also is involved with memory, thinking, learning, reasoning, problem-solving, emotions, consciousness. No wonder vision it is so central to our understanding of the human experience, that part of the experience that lies outside of the realm of just striving to survive. And it all begins by being sensitive to just 3 colors and light-dark contrast.

But if you are going to leave with one thought, it’s realizing we are all in a way imagining what’s around us. It’s some kind of trick, albeit a very reliable and important one, but still a trick. Your eyes, your brain, your consciousness are three separate entities that feel like one but are not. It’s an amazing reality, and a truly amazing ability that we have really only just started to understand. Things really are not what they seem. Try to remember that the next time you look into a loved ones eyes, see the sun set, watch a beautiful film, take in your favorite painting, and if you can when you dream.

Thank you for your time. I hope you found this useful, entertaining, informative or all of the above.

I’ll see you next time on Remedial Polymath!

Optical illusions:

For a great article about optical illusions with information about their history, why they work and examples head to: https://www.bbc.com/future/bespoke/story/20150130-how-your-eyes-trick-your-mind/index.html

For a great video about optical illusions check out the video underneath this article.

​Resources:

https://my.clevelandclinic.org/health/articles/23073-cerebral-cortex
https://www.rochester.edu/pr/Review/V74N4/0402_brainscience.html
https://en.wikipedia.org/wiki/Electromagnetic_spectrum
https://www.ncbi.nlm.nih.gov/books/NBK10848/
https://www.yorku.ca/eye/receptor.htm
https://www.wired.com/story/a-single-math-model-explains-many-mysteries-of-vision/?bxid=5be9d6c324c17c6adf3e921f&cndid=21353573&esrc=bounceX&source=EDT_WIR_NEWSLETTER_0_DAILY_ZZ&utm_brand=wired&utm_campaign=aud-dev&utm_mailing=WIR_Daily_082619&utm_medium=email&utm_source=nl&utm_term=list2_p2&verso=true
https://www.wired.com/story/why-we-see-the-colors-of-faces-differently-than-other-things/
https://www.flinnsci.com/api/library/Download/799325c77ea0493bae7283328700ecb7
https://en.wikipedia.org/wiki/Photoreceptor_cell