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Sensations into symbols
You won’t believe your eyes: The mysteries of sight revealed
Vision in the womb
http://www.abc.net.au/rn/talks/
8.30/helthrpt/stories/s73272.htm
The true story of the Cyclops
Teaching the skin to see

Since the early 1970s, Paul Bach-y-Rita has been building prosthetic eyes for the blind: not false eyes, not glass eyes, but fully working organs of vision. With them, Bach-y-Rita – a biomedical engineer at the University of Wisconsin-Madison – has helped the blind to see.
His eyes do not look like eyes. The earliest models look like clothing. Bach-y-Rita’s vests are worn either across the stomach or across the back. Sewn into the material are 256 mechanical vibrators (nicknamed ‘tactors’ because, when they’re activated, the subject can feel their touch). A computer worn at the hip recieves pixellated images from an ultra-low resolution video camera, worn on a pair of eyeglasses, and translates these images into mechanical vibrations, via the tactors. The upshot is a kind of Braille or Pin Art vision.
Bach-y-Rita’s subjects reported that after a couple of hours they were no longer aware of the tingling sensations generated by the vest. They were able to navigate between obstacles, and, eventually, to recognise faces. When the ‘view’ before them changed – because they moved, or because something moved in front of them – they reacted appropriately to the change of view. If you screwed up a piece of paper and threw it at them, they would duck.
Even more suggestive is an experiment reported by Daniel Dennett in which a researcher, without warning, manipulated a zoom button on a volunteer’s camera, making it seem as though he were hurtling forward. The volunteer raised his hands to protect his face. But his vest was strapped to his back.(1)
The artificial sense bestowed upon his blind volunteers by Paul Bach-y-Rita not only works like vision – it feels like vision. It seems that the mind is not overly fussy where it gets its sensory information from. What matters is what ‘shape’ the information takes. If visual information is received through the skin of your back, it only takes your brain a couple of hours to start seeing through your back. If your back starts itching, on the other hand, you won’t mistake the itch for a flash of light. The ‘shape’ of an itch is different to the ‘shape’ of, say, a face, and the brain knows how to deal with each.
(1) Dennet, D. 1991. Consciousness Explained. New York, Little Brown & Company, pp339-342
Matters of light and darkness
How well do you see in the dark? Edward Halsall, a royalist major during the Cromwell era, was imprisoned for twenty months in a windowless room. It took Halsall’s eyes seven months to adjust fully to the dark, but by the end of his imprisonment, he ‘could see the mice that used to feed upon his leavings’; ‘well enough’, indeed, ‘to make a mousetrap with his cup.’ Humans have excellent night vision. (We are, after all, the descendants of nocturnal shrews.) And it’s by juggling two quite distinct forms of vision – one adapted to the dark, the other to the light – that our eyes can cope with virtually any lighting conditions.
This is as well: on a sunny day, our eyes receive a million times as much light as they can gather on a clear, moonless night. How can our eyes cope with such staggeringly different light levels?
In 1867, a young physicist called Ernst Mach pondered this optical illusion. Arrange a series of grey bands, each band slightly lighter than its neighbour, and they look as though they have been lit from the side. The edges lying against darker neighbours appear lighter, while edges lying against lighter neighbours appear darker. The fluting is an illusion, obviously – but why should the eye manufacture dark where there is no dark, and light where there is no light?
Spotting boundaries is essential to vision. Without boundaries, the edges of objects become uncertain, and objects simply bleed away into the background. So the eye manufactures shading to reveal the forms of objects. Mach worked out the mathematics of how the eye could do this. It was a brilliant piece of work, still used today. (Bang & Olufsen’s new televisions handle contrast and picture detail in an intelligent manner by applying algorithms first dreamt up by Mach, nearly a century and a half ago.)
In the 1930s, American physiologist Haldan Keffer Hartline identified the parts of the eye that performed Mach’s mathematical magic tricks; and, in doing so, he discovered something surprising. When the eye studies an evenly illuminated surface, its optic nerve falls silent. The eye can handle a million-fold difference in light level because the eye doesn’t measure the light level at all. All it ever reports are small, local variations in light intensity. Look very closely at portrait of Che Guevara, – a delightful visual puzzle dreamt up five years ago by Dr Steven Dakin of University College, London. You will see, if you look closely enough, that the lit parts of Che’s face are exactly the same shade of grey as his beard and facial shadows. It’s the banded line that tells your eye which side of the line is supposed to be light, and which side is supposed to be dark – and it’s your eyes that then add shading to the picture.
Our perception of colour, too, is a matter of contrast. Vivid as the colours around us seem, their brilliance is manufactured in the eye. Our eyes gauge the brightness, hue and vividness of patches of colour by relating them to the shade, hue and vividness of their surroundings, and we can draw figures, like the ones here, to show how the same colour looks very different when it appears in different surroundings.
Simple figures like these seem to trick the eye into error. But in the rich visual environment of the real world – a world full of multiple light sources, shimmering reflections, dappled shadows, and complex three-dimensional patchworks – our style of vision enables us to identify the colours of things with extraordinary accuracy.
Oddly, this point that was lost on vision science until midway through the last century, and the arrival of Edwin Land. Land was, after Thomas Edison, America’s most prolific inventor. Polaroid photography is just one of his inventions. Land’s startling experiments and demonstrations showed how robust our colour vision is under different lights. He prepared boards of intersecting multicoloured shapes (called ‘mondrians’, after the artist whose work they resembled) and lit them with lamps of different hues. People studying the mondrians described their colours accurately even under the most bizarrely tinted lighting.
But Land’s most famous ‘experiment’ happened by accident. Land and his team were using red, green and blue lights to produce a true-colour image on a screen (cathode-ray televisions work this way). Come evening, Land and his assistants shut off the blue projector and took the green filter out of the green projector. It was then that one of the assistants called Land’s attention to the screen. The red projector was still running, and the unfiltered green projector was projecting its image over the top of the reds in white light. And there, upon the screen, was the original full-colour image. Red and white lights were throwing blues and greens upon the screen! Land realised that the eye was using the little information it had to colour in the image, just as your eye shades in the portrait of Che Guevara.
Our eyes make things up. They snatch trickles of light from a world of blur and shadow, and they manufacture pictures of the world that are both coherent and true. The optical illusions on these pages do not ‘fool’ the eye – rather, they persuade it to reveal its creative power. They show us why, in the real world, we can believe our eyes.
The tell-tale eye
‘My boy, I wish you to witness an experiment.’ He drew from its case a powerful microscope of French make.‘What on earth are you going to do, sir?’The doctor’s brilliant eyes flashed with a mystic light as he replied: ‘Find the fiend who did this crime—and then we will hang him on a gallows so high that all men from the rivers to the ends of the earth shall see and feel and know the might of an unconquerable race of men.’—Thomas Dixon Jr, The Clansman (1905)
Fiction by numbers
Aritha van Herk in the Calgary Herald, August 13, 2006. http://bit.ly/KKaYT
As if befuddled by numbers, which have always daunted me, I have to dial Simon Ings’ telephone number in London several times before I get it right. I have no excuse for befuddlement; but having just become father to a brand new baby, Ings does. He, however, is bright and chipper, enjoying the attention his new novel, The Weight of Numbers, is receiving, looking forward to his upcoming visit to Canada, and to performing at Calgary’s International Word Fest. Because of his new child, we talk for a few moments about children’s stories and how they have become anodyne.
Ings tells me that he creates interesting variations for his children. “They love blood and gore. Leave them alone and listen behind the door and you can feel your blood curdle,” he says, laughing. But he is pragmatic too. “The worst crime you can commit as a parent is to be dull.” Dull Simon Ings is not. Best known as a science fiction or cyberpunk writer, his latest book has earned him comparisons to Paul Auster and Don DeLillo. Like them, Ings takes as his subject how humans cruise the hyperventilated contemporary world. With this work, The Weight of Numbers, Ings shifts ground from the future to the present, from genre fiction to serious literary style. It is a sprawling labyrinth of a novel, not at all linear, and daunting in its reach and ambition. Ings tells me, “it was originally going to be a book of inter-linked stories. I had written fairly small brash books before, but with this book, I was re-inventing myself as a writer. “I wanted to create a poly-historical novel, like Kundera does, one that works through theme rather than narrative. But perhaps because I’ve spent my life writing thrillers and science fiction, my plot head could not be silenced. What I discovered is that the world is bigger than you are; and that all stories connect to one another.” If there is one unifying principle in The Weight of Numbers it is that, despite the randomness of time and circumstance, humans cannot escape connection — the six degrees of separation rule. Ings claims, “the whole point of the book is connection, and that everything is connected to everything else.” At the same time, he is pragmatic, observing that writing about “six degrees of separation is itself a moment that has probably come to its end.” This great sprawling novel is both great and sprawling, its subject the 20th century itself, time made small and history inescapable. The back stories that twine through the book include astronauts and wrestlers, truckers and astronauts, anorexic actresses and kidnapped children. It moves from the war in Mozambique to the Blitz in London, touches down in Portsmouth, Chicago, Cape Canaveral, Portugal, Havana, and outer space. It mixes real people with fictional characters. Geri Halliwell, Vanessa Redgrave and Ewan McGregor make cameo appearances. Neil Armstrong puts his foot down on the dust of the moon. The Weight of Numbers zigzags between revolutions and accidents, outer space and personal space, genocide and anorexia. And yet, for all this shifting chiaroscuro of characters and places, rackets and raconteuring, The Weight of Numbers is ultimately poignant and intimate, a portrait of this brave new world we inhabit spinning patiently through darkness. The causal connections between humans and events, politics and poetry, might seem incidental, but they map the terra incognita of accident and activism, and how we are all, in some indecipherable way, knotted together. Ings isn’t so much philosophical about the novel’s big sweep as he is modest. “I think for me the plot is really these characters learning how to put up with human unhappiness; they begin with a sense of personal size, but walk away aware of the limitations of ordinary life.” “To actually develop idea, I found myself needing a much larger canvas. I am not a good enough writer to be able to play that arc out in a handful of pages, although there are lots of short story writers who can turn a life on a penny. I wanted to explore a broader canvas, the ruin of history.” The Weight of Numbers travels far and furiously, with characters both participants in and witnesses to key moments of history. It’s jittery and jet-setting, and it asks the reader to forego the usual expectations of cause and effect. Ings has written a novel utterly contemporary in its conception and preoccupation, as if translating the multiple sites of the World Wide Web into fiction. The difficulty is whether our attenuated attention spans can manage such demanding reading. Ings himself has a lifetime of experience under his belt. When I ask him about his research methods, he mentions that he has written about “the world of wrestling, the theatre of war, sports, trade, and teaching.” He tells me about attending a competition for the world’s strongest women. “I got to meet the world’s strongest women. They were like climbers, dedicated, obsessed, intelligent. They took their bodies completely seriously, hanging from beams, lifting weights.” He’s travelled all over the world, to Oman, Dubai, Helsinki, Burma. He wrote his 1994 novel, The City of the Iron Fish, in six weeks in a brothel in Oporto, Portugal. Not many writers could pull off a novel that is really about the 20th century and its melting of space, time and ideology. Does he believe that we are all ghosts in the globalized machine? “Politics,” he says carefully, “is a human business, what happens if ideology has stopped and survival becomes just a numbers game. Ideology can lead to interesting experiments, but as a life philosophy, it is easily punctured. At the same time, in a lot of the world, where ideology really counts, it can be a life and death matter. “There’s a sense at the end of the book that all politics have been thrown away and that ideology doesn’t work because it can’t move fast enough to match history. Only people can will human life and work in favour of better human conduct.” Ings won the the Arena O2 X Award for The Weight of Numbers. He tells me that it’s an “ordinary” award for which he got “a hug and a perspex Joe Strummer (guitarist for the Clash) statuette.” Because he has always written reviews and articles for Science magazines, his agent suggested that he write a science book. “Like an idiot I took him on,” says Ings. The resulting tome, The Eye: A Natural History, will appear next year. “You would think that there would be a book on the eye. But there is no book on the eye as a subject. There are books on the human eye, the aging eye, the evolution of the eye, but no single book on the eye. It’s been an albatross around my neck.” Simon Ings may think that he made a mistake in undertaking a comprehensive book about the eye. But if The Weight of Numbers is any indication, it will be as clear-sighted and fascinating as the man himself. And it will be, without question, beautifully written. Ings promises to be one of the highlights of this fall’s Word Fest, original and yet as human as mathematical probability will allow. Aritha van Herk can add, subtract, balance a chequebook and imagine probability. She lives and writes in Calgary.