Usually when you think of optical illusions you're thinking of something that's messing with your brain; "Look all the dots are wobbling!" "Look, that staircase is impossible!" "Look, the candlestick is two faces!" and so on. But really we rely on optical illusions all day, every day. Without them could we look at a photograph and make sense of it? Understand a representational illustration? See a movie, without the illusion of motion? I'm going to say that no, we probably couldn't, and that such art forms are as reliant on illusions that can fool our brains into seeing something that isn't there as novelty videos of dragons who's heads follow you around the room. Illusions are central to our understanding of art - they make art possible, and yet at the same time they make art very difficult. We'll get to the why of that in a later post, but first let's look at some common illusions and why I believe they make a case for art, in general, being dependent on them.
Before we continue I should point out that this essay is going to be a bit of a ramble, and will be split into two parts (the next coming soon). I have a copy of Sketch Book Pro open in one window, and I'm writing this in the other. I am hoping it will all tie up neatly with a nice bow, but I'm not writing it for my English lecturer so I'm just going to go with the flow and hope for the best (If you're lucky I'll proof read it before publishing). As usual in these posts there's the caveat that I'm not an expert in this stuff, and I'm definitely not qualified in these areas, so you probably don't want to quote me in case I'm an idiot :)
What we have above are quick examples of the Kanizsa Triangle and the Phenomena known as Pareidolia - here specifically applied to faces and expressions. No, I didn't use a ruler, obviously.
The Kanizsa Triangle, also known more broadly as Illusionary Contours, and sometimes specifically as The Pacman Triangle (which is a great description) was first described by Gaetano Kanizsa back in 1955, although people had at least been aware of it for at least a few millennia before that; but if you don't make notes you don't get things named after you I guess - unless you're awesome, like Pacman. It's fairly easy to ascertain that people were aware of this illusion before 1955 because it's a fundamental aspect of our understanding of art (and of our visual understanding of things in general - It's called Amodal Perception). Not all art, but rather a lot of it. It's also a key element of the Rubin's Vase Illusion (Sometimes called the Candlestick and Faces Illusion), which dates from around 1915. Examples of it can also be seen in woodcuts going back centuries, but I'm far to lazy to go and find any as an example right now.
Pareidolia is considered a psychological phenomena rather than an optical illusion, but since so many optical illusions are really a result of what out brains do with the information sent to them by the optic nerves I can't help but feel that that's splitting hairs a little. It does occur with other stimuli as well though; A creak in the house you perceive as a footstep, or an itch that feels like a bug is sitting on you (at least that's how I understand it). For visual stimuli it's what's responsible for us seeing elephants and horses in the clouds, hungry helicopters, faces in cliffs (naturally that is, Crazy Horse and Mount Rushmore probably don't count, although they likely only really work because of the same phenomenon), or deities in common bread products.
So these are two fairly common illusions, ones we're fairly used to, and ones that we generally put down to either our eyes, or our brains playing tricks on us. Yet both of them (and many similar optical illusions) are fundamental to our understanding of art and the world. Lets take a look at a couple of other images.
On the left we have Sherlock Holmes (as depicted by Basil Rathbone -though the likeness is terrible, it wasn't the point of the exercise), while on the right we have a portrait of a woman (based on a photo of Jean Ackerman, though again the likeness wasn't the point - I'm trying not to spend very long on these images, and this failure of likeness will actually feed into a point in the next related post).
And we can see what they are - they are very clearly a profile of a man in a hat with a pipe, and a woman seen from about 3/4 view. There is no tonal detail here, just black and white shapes that would be nearly meaningless if taken in isolation (more for the picture of Holmes than Ackerman). The illusions mentioned above working in parallel to fool our eyes into seeing an image that does not actually exist; more so because we don't see the world like this, even when it's dark and we only see in monochrome, this is an entirely artificial construct within our minds.
Here we have three images. The first is a collection of shapes; the same ones that went into making the image of Sherlock Holmes, but this times moved and rotated into an unrecognizable jumble - although you can probably still make out his pipe. Despite this being a random rearranging of those previous shapes if you're anything like me you will still find your brain trying to make some kind of sense of the mess. I can see a man's profile and a stylized animals head - I have to wonder what it is you might find.
The second and third images are just quick tests to see how little information is required for the brain to do its thing. One of these two men is made up of only two specific dark shapes, the other consists of only one, yet we can tell they are most likely male, roughly what their hair is like, their expression, and can make out certain features explicitly. If these were based on photographs they might even be recognizable. Our brains are mad powerful. I didn't take it any further than this for this post, but before the next one I'll see if it's possible to create a recognizable face with even less (faces tend to be much easier to make out than other things, at least for me).
The last image for today is basically the same image twice, but showing two different things (I had to open Photoshop for this one, but I needed to crop the other images anyway). On the left we have another example of Illusionary Contours and Pareidolia working in tandem to create a relatively complex image from only three main shapes. On the right the same image is used as an example of how little additional information is required to add the illusion of solidity. This second also demonstrates another common illusion (although not terribly well). The squares on the cube look as though they are illuminated from within due to them being so much brighter than the cube itself, especially the one in the darker face, but beyond and despite this the square on the top of the cube; which, you'll note, is not really a square at all, looks fractionally darker than the one facing us.
So with these in mind, we can extrapolate (because I'm done typing for now) that other optical illusions are also at play with our understanding of art. Motion pictures use the persistence of vision for example. (I'd put money on a publication or letter dated between 1830 and 1860 having described a zoetrope, then called a daedalum, as some arcane optical illusion (they also called it the Wheel of the Devil, so you can bet they didn't think this phenomenon was exactly common place, while today we consider it perfectly normal. Amazing what you can find out on Wikipedia).
The reasons for many of these illusions, and the ones I'll cover next time are twofold as I understand it. Firstly the brain's job is to make sense of what the eyes can see as quickly and accurately as possible. Given the choice between accuracy and speed, speed is going to win every time. Better to run away from that cluster of shadows that looked a bit like a tiger than to stay put and get eaten because the brain was still trying to make sense of the stripes against the shadows of the grass.
The second reason is that all that information needs to be stored, and as amazing as the brain is it's probably not as efficient as most computer memory. So there's an enormous amount of information needing to be stored in a very small space and not the most efficient method for storing it. As a result things need to be compressed in the most efficient manner possible, and while most of that occurs during storage (probably between short term memory and long term if I was to guess - if I knew neuroscience I'd likely be better paid), I'm willing to bet that it begins with the decoding of the visual information into information we can understand. I'll go into my thoughts on that score next time around when I'll discuss how the very illusions that make art possible also make it surprisingly hard to produce.
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