Joe Banks is an installation artist and researcher, and author of the book “Rorschach Audio – Art & Illusion for Sound” –

Visual reality is in itself a carefully constructed optical illusion


Writing in 1753, in his theoretical magnum-opus “The Analysis of Beauty”, the artist William Hogarth observed that “the mind itself may be so imposed upon as to make the eye see falsely as well as truly”, with the effect that, were it not for the control that the mind exercises over vision, “we should not only see things double, but upside-down, as they are painted upon the retina, and as each eye has distinct sight”. Hogarth also asserted that “experience teaches us that the eye may be subdued and forced into forming and disposing of objects even quite contrary to what it would naturally see them, by the prejudgment of the mind”, stating that “surely this extraordinary perversion of the sight would not have been suffr’d, did it not tend to great and necessary purposes, in rectifying some deficiencies which it would otherwise be subject to” (original spellings).

So, it’s been known for centuries that the light received by human eyes is projected through the pupil onto the back of each eye, so that the images formed on the retina are optically upside-down; and it’s obvious from this fact alone that it is the mind which inverts the images we actually perceive, so that our visual sense can be practically useful for the safe navigation of our environment. Likewise, as Hogarth was also aware, it is sometimes easy to overlook the fact that the information provided by the eyes consists of not one but two images, and that it is again our minds which fuse these images into the single perceptual construct that we perceive as being visual reality.

William Hogarth’s observations about what today we’d refer to as cognitive neuroscience, appeared in context of the broader discourse contained in his book. The central focus of “The Analysis of Beauty” was Hogarth’s discussion of the aesthetics and symbolism of the S-shaped, waving, or (as Hogarth put it) “Serpentine” line – the elegant sinusoidal form which Hogarth posited as the essence of beauty, which is the same line that modern physics & mathematics refer to as the sine-wave. Under the aegis of the electronic music and art project Disinformation, I exhibit an art installation called “The Analysis of Beauty”, which uses musical signals from laboratory sine-wave generators, which are made visible as Serpentine Lines on the screen of a laboratory oscilloscope. The pattern on the oscilloscope screen strongly resembles DNA, and the exhibit was described as “visually sophisticated” and “distinctive and intelligent” by Art Monthly, and as “particularly sensuous” by The Wire magazine.

Visual aesthetics aside however, the installation has another trick up its’ sleeve. After watching these lines move for a little while, it’s easy to persuade the lines to fuse into a what appears to be a solid object. Sometimes the form appears to be flat, sometimes three-dimensional. Sometimes the object seems to rotate to the left, sometimes to the right. Sometimes the direction changes spontaneously, and sometimes blinking, tilting your head, and even thinking about the object in a different way can induce changes in direction. The point to be aware of here is that none of the changes you see take place on-screen. All of these changes take place inside your own mind!

In fact sometimes vivid illusions of three-dimensional form emerge, despite the absence of all the object-precedence, geometric and aerial perspective, motion parallax, texture gradient, stereoscopic and binocular visual cues conventionally thought to enable perception of visual depth and space. We perceive visual depth because close objects physically obscure more distant objects, because the build-up of atmospheric haze causes distant objects to appear faint and visually blurred, because distant objects become visually smaller and objects and lines recede towards vanishing points, because the brain interprets the divergent views of objects received by the left and right eyes, and because we understand how objects move relative to each other in visual space. To invoke examples of just 2 of those sources of information listed above, think for instance of the striking illusions of depth that binocular vision produces in 3D cinema, or of the legendary “Father Ted” sketch – “these [cows] are small, but the ones out there are… far away”.

In the case of “The Analysis of Beauty” installation, we perceive visual depth with none of the aforementioned cues. It is instead our knowledge which informs guesses about what shapes certain ambiguous patterns are likely to form in the real world, and our minds project these guesses out onto the raw “sense data” that was received by our eyes. Similar processes occur in the perception of some famous optical illusions – such as the visually-reversing Necker Cube, the 2 facial silhouettes that, when looking towards each other, resemble a wine-glass, the astonishing Reverspective paintings of the artist Patrick Hughes, and the duck-rabbit illusion, etc. The paradox is that although the “perceptual hypotheses” produced by such images result in visual illusions, we experience those illusions as visually “real”, and, from the point-of-view of cognitive neuroscience, the ramifications of that fact are absolutely profound.

Article copyright © Joe Banks May 2016

The Analysis of Beauty

Father Ted


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