by Oliver Sacks
We achieve perceptual constancy—the correlation of all the different appearances, the transforms of objects—very early, in the first months of life. It constitutes a huge learning task, but is achieved so smoothly, so unconsciously, that its enormous complexity is scarcely realized (though it is an achievement that even the largest supercomputers cannot begin to match). But for Virgil, with half a century of forgetting whatever visual engrams he had constructed, the learning, or relearning, of these transforms required hours of conscious and systematic exploration each day. This first month, then, saw a systematic exploration, by sight and touch, of all the smaller things in the house: fruit, vegetables, bottles, cans, cutlery, flowers, the knickknacks on the mantelpiece—turning them round and round, holding them close to him, then at arm’s length, trying to synthesize their varying appearances into a sense of unitary objecthood. 72
72. There were similar problems with Gregory’s subject, S.B., who never ceased to be “struck by how objects changed their shape when he walked round them—He would look at a lamppost, walk round it, and stand studying it from a different aspect, and wonder why it looked different and yet the same.” All newly sighted subjects, indeed, have radical difficulties with appearances, finding themselves suddenly plunged into a world that, for them, may be a chaos of continually shifting, unstable, evanescent appearances. They may find themselves completely lost, at sea, in this flux of appearances, which for them is not yet securely anchored to a world of objects, a world of space. The newly sighted, who have previously depended on senses other than vision, are baffled by the very concept of “appearance”, which, being optical, has no analogue in the other senses. We who have been born into the world of appearances (and their occasional illusions, mirages, deceptions) have learned to master it, to feel secure and at home in it, but this is exceedingly difficult for the newly sighted. The philosopher F.H. Bradley wrote a famous book called Appearance and Reality (1893)—but for the newly sighted, at first, these have no connection.
Despite all the vexations that trying to see could entail, Virgil had stuck with this gamely, and he had learned steadily. He had little difficulty now recognizing the fruit, the bottles, the cans in the kitchen, the different flowers in the living room, and other common objects in the house.
Unfamiliar objects were much more difficult. When I took a blood-pressure cuff from my medical bag, he was completely flummoxed and could make nothing of it, but he recognized it immediately when I allowed him to touch it. Moving objects presented a special problem, for their appearance changed constantly. Even his dog, he told me, looked so different at different times that he wondered if it was the same dog. 73
73. When Virgil said this I was reminded of a description in Borges’s story “Funes the Memorious”, where Funes’s difficulty with general concepts leads him into a similar situation:
It was not only difficult for him to understand that the generic term dog embraced so many unlike specimens of different sizes and forms; he was disturbed by the fact that a dog at three-fourteen (seen in profile) should have the same name as the dog at three-fifteen (seen from the front).
He was utterly lost when it came to the rapid changes in others’ physiognomies. Such difficulties are almost universal among the early blinded restored to sight. Gregory’s patient S.B. could not recognize individual faces, or their expressions, a year after his eyes had been operated on, despite perfectly normal elementary vision.
What about pictures? Here I had been given conflicting reports about Virgil. He was said to love television, to follow everything on it—and, indeed, a huge new TV stood in the living room, an emblem of Virgil’s new life as a seeing person. But when we tried him first on still pictures, pictures in magazines, he had no success at all. He could not see people, could not see objects—did not comprehend the idea of representation. Gregory’s patient S.B. had similar problems. When shown a picture of the Cambridge Backs, showing the river and King’s Bridge, Gregory tells us:
He made nothing of this. He did not realize that the scene was of a river, and did not recognize water or bridge—
So far as we could tell, S.B. had no idea which objects lay in front of or behind others in any of the color pictures—We formed the impression that he saw little more than patches of color.
It was similar, again, with Cheselden’s young patient:
We thought he soon knew what pictures represented—but we found afterwards we were mistaken; for about two months after he was couched, he discovered at once they represented solid bodies, when to that time he considered them only as party-coloured planes, or surfaces diversified with variety of paint; but even then he was no less surprised, expecting the pictures would feel like the things they represented,—and asked which was the lying sense, feeling or seeing?
Nor were things any better with moving pictures on a TV screen. Mindful of Virgil’s passion for listening to baseball games, we found a channel with a game in progress. It seemed at first as if he were following it visually, because he could describe who was batting, what was going on. But as soon as we turned off the sound he was lost. It became evident that he himself perceived little beyond streaks of light and colors and motions, and that all the rest (what he seemed to see) was interpretation, performed swiftly, and perhaps unconsciously, in consonance with the sound. How it would be with a real game we were far from sure—it seemed possible to us that he might see and enjoy a good deal; it was in the two-dimensional representation of reality, pictorial or televisual, that he was still completely at sea.
Virgil had now had two hours of testing and was beginning to get tired—both visually and cognitively tired, as he had tended to do since the operation—and when he got tired he could see less and less, and had more and more difficulty making sense of what he could see. 74
74. Due to his exhaustion at this point, we could not test him on the visual illusions we had brought along. This was unfortunate, because “seeing” or “not seeing” visual illusions provides an objective and replicable way of examining the visual-constructive capacities of the brain. No one has explored this approach more deeply than Gregory, and his detailed account of S.B.’s responses to visual illusions is therefore of great interest. One such illusion consists of parallel lines that, to normal eyes, seem to diverge because of the effect of diverging lines superimposed on them; no such “gestalt” effect occurred with S.B., who saw the lines as perfectly parallel—a similar lack of “influence” was seen with other illusions. Particularly interesting was S.B.’s response to reversing figures, such as cubes and staircases drawn in perspective, which are normally seen in depth and reverse their apparent configuration at intervals; the figures did not reverse for S.B. and were not seen in depth. There was, similarly, no figure-ground fluctuation with ambiguous figures. He did not, apparently, “see” distance⁄size changes in illusions, nor did he experience the so-called waterfall effect, the familiar aftereffect of perceived movement. In all these cases, the illusion is “seen” (even though the mind may know the perception to be illusory) by all normally sighted adults. Many of these illusory effects can also be demonstrated in young children, and some in monkeys, and even in Edelman’s artificial “creature”, darwin iv. That S.B. failed to “see” them illustrates how rudimentary his brain’s powers of visual construction were, in consequence of the virtual absence of early visual experience.
Indeed, we were getting restless ourselves and wanted to get out after a morning of testing. We asked him, as a final task before going for a drive, if he felt up to some drawing. We suggested first that he draw a hammer. (A hammer was the first object S.B. drew.) Virgil agreed and, rather shakily, began to draw. He tended to guide the pencil’s movement with his free hand. (“He only does that because he’s tired now”, said Amy.) Then he drew a car (very high and old–fashioned); a plane (with the tail missing: it would have been hard put to fly); and a house (flat and crude, like a three-year-old’s drawing).
When we finally got out, it was a bril
liant October morning, and Virgil was blinded for a minute, until he put on a pair of dark-green sunglasses. Even ordinary daylight, he said, seemed far too bright for him, too glary; he felt that he saw best in quite subdued light. We asked him where he would like to go, and after thinking for a little he said, “The zoo.” He had never been to a zoo, he said, and he was curious to know how the different animals looked. He had loved animals ever since his childhood days on the farm.
Very striking, as soon as we got to the zoo, was Virgil’s sensitivity to motion. He was startled, first, by an odd strutting movement; it made him smile—he had never seen anything like it. “What is it?” he asked.
“An emu.”
He was not quite sure what an emu was, so we asked him to describe it to us. He had difficulty and could say only that it was about the same size as Amy—she and the emu were standing side by side at that point—but that its movements were quite different from hers. He wanted to touch it, to feel it all over. If he did that, he thought, he would then see it better. But touching, sadly, was not allowed.
His eye was caught next by a leaping motion nearby, and he immediately realized—or, rather, surmised—that it must be a kangaroo. His eye followed its motions closely, but he could not describe it, he said, unless he could feel it. We were wondering by now exactly what he could see—and what, indeed, he meant by “seeing.”
In general, it seemed to us, if Virgil could identify an animal it would be either by its motion or by virtue of a single feature—thus, he might identify a kangaroo because it leapt, a giraffe by its height, or a zebra by its stripes—but he could not form any overall impression of the animal. It was also necessary that the animal be sharply defined against a background; he could not identify the elephants, despite their trunks, because they were at a considerable distance and stood against a slate-colored background.
Finally, we went to the great-ape enclosure; Virgil was curious to see the gorilla. He could not see it at all when it was half-hidden among some trees, and when it finally came into the open he thought that, though it moved differently, it looked just like a large man. Fortunately, there was a life-size bronze statue of a gorilla in the enclosure, and we told Virgil, who had been longing to touch all the animals, that he could, if nothing else, at least examine the statue. Exploring it swiftly and minutely with his hands, he had an air of assurance that he had never shown when examining anything by sight. It came to me—perhaps it came to all of us at this moment—how skillful and self-sufficient he had been as a blind man, how naturally and easily he had experienced his world with his hands, and how much we were now, so to speak, pushing him against the grain: demanding that he renounce all that came easily to him, that he sense the world in a way incredibly difficult for him, and alien. 75
75. Earlier, Virgil had picked up the distant sound of lions roaring in their enclosure; he pricked up his ears and turned instantly in their direction. “Listen!” he said. “It’s the lions—they’re feeding the lions.” The rest of us had completely missed the sound and, even when Virgil drew our attention to it, found it faint and were unsure which direction it came from. We were struck by the quality of Virgil’s hearing, his auditory attention and acuteness and orientation, how extremely skilled as a listener he was. Such an acuteness and a heightening of auditory sensitivity occur in many blind people, but above all in those born blind or blinded early in life; it seems to go with the constant focusing of attention and affect and cognitive powers in these spheres, and, with this, a hyperdevelopment of auditory-cognitive systems in the brain.
His face seemed to light up with comprehension as he felt the statue. “It’s not like a man at all”, he murmured. The statue examined, he opened his eyes, and turned around to the real gorilla standing before him in the enclosure. And now, in a way that would have been impossible before, he described the ape’s posture, the way the knuckles touched the ground, the little bandy legs, the great canines, the huge ridge on the head, pointing to each feature as he did so. Gregory writes of a wonderful episode with his patient S.B., who had a longstanding interest in tools and machinery. Gregory took him to the Science Museum in London to see its grand collection:
The most interesting episode was his reaction to the fine Maudeslay screw cutting lathe which is housed in a special glass case—We led him to the glass case, which was closed, and asked him to tell us what was in it. He was quite unable to say anything about it, except that he thought the nearest part was a handle—We then asked a museum attendant (as previously arranged) for the case to be opened, and S.B. was allowed to touch the lathe. The result was startling—He ran his hands eagerly over the lathe, with his eyes tight shut. Then he stood back a little and opened his eyes and said: “Now that I’ve felt it I can see.”
So it was with Virgil and the gorilla. This spectacular example of how touching could make seeing possible explained something else that had puzzled me. Since the operation, Virgil had begun to buy toy soldiers, toy cars, toy animals, miniatures of famous buildings—an entire Lilliputian world—and to spend hours with them. It was not mere childishness or playfulness that had driven him to such pastimes. Through touching these at the same time he looked at them, he could forge a crucial correlation; he could prepare himself to see the real world by learning first to see this toy world. The disparity of scale did not matter, any more than it mattered to S.B., who was instantly able to tell the time on a large wall clock because he could correlate it with what he knew by touch from his pocket watch.
For lunch, we repaired to a local fish restaurant, and as we ate I stole glances, from time to time, at Virgil. He started eating, I observed, in the normal sighted fashion, accurately spearing segments of tomato in his salad. Then, as he continued, his aim grew worse: his fork started to miss its targets, and to hover, uncertainly, in the air. Finally, unable to “see”, or make sense of, what was on his plate, he gave up the effort and started to use his hands, to eat as he used to, as a blind person eats. Amy had already told me about such relapses and described them in her journal. There had been similar reversions, for example, with his shaving, where he would start with a mirror, shaving by sight, with tense concentration. Then the strokes of the razor would become slower, and he would start to peer uncertainly at his face in the mirror, or try to confirm what he half saw by touch. Finally, he would turn away from the mirror, or close his eyes, or turn the light off, and finish the job by feel.
That Virgil should have periods of acute visual fatigue following sustained visual effort or use was scarcely surprising; all of us have them if too much is demanded of our vision. Something happens to my own visual system if, for instance, I look at EEGs nonstop for three hours: I start missing things on the traces, and seeing dazzling afterimages of the squiggles wherever I look—the walls, the ceiling, all over the visual field—and at this point I need to stop and do something else, or, even better, close my eyes for an hour. And Virgil’s visual system, by comparison with the normal one, must have been at this stage labile in the extreme.
Less easy to understand, and alarming, perhaps ominous, were long periods of “blurriness”—impaired vision or gnosis—lasting hours or even days, coming on spontaneously, without obvious reason. Bob Wasserman was very much puzzled by Virgil’s and Amy’s descriptions of these fluctuations; he had been practicing ophthalmology for some twenty-five years and had removed many cataracts, but he had never encountered fluctuations of this sort.
After lunch, we all went to Dr. Hamlin’s office. Dr. Hamlin had taken detailed photographs of the retina right after surgery, and Bob, examining the eye now with both direct and indirect ophthalmoscopy and comparing it with the photographs, could see no evidence of any postoperative complications. (A special test—fluorescein angiography—had shown a small degree of cystoid macular edema, but this would not have caused the rapid fluctuations that were so striking.) Because there seemed to be no adequate local or ocular cause for these fluctuations, Bob wondered whether they could be a consequence of some
underlying medical condition—we had been struck by how unwell Virgil looked as soon as we met him—or whether they could represent a neural reaction of the brain’s visual system to conditions of sensory or cognitive overload. It is no effort for the normally sighted to construct shapes, boundaries, objects, and scenes from purely visual sensations; they have been making such visual constructs, a visual world, from the moment of birth, and have developed a vast, effortless cognitive apparatus for doing so. (Normally, half of the cerebral cortex is given over to visual processing.) But in Virgil these cognitive powers, undeveloped, were rudimentary; the visual-cognitive parts of his brain might easily have been overwhelmed.
Brain systems in all animals may respond to overwhelming stimulation, or stimulation past a critical point, with a sudden shutdown. 76
76. Pavlov, speaking of such responses in dogs, called this “transmarginal inhibition consequent upon supramaximal stimulation”, and regarded these shutdowns as protective in nature.
Such reactions have nothing to do with the individual or his motives. They are purely local and physiological and can occur even in isolated slices of cerebral cortex: they are a biological defense against neural overload.
Still, perceptual-cognitive processes, while physiological, are also personal—it is not a world that one perceives or constructs but one’s own world—and they lead to, are linked to, a perceptual self, with a will, an orientation, and a style of its own. This perceptual self may itself collapse with the collapse of perceptual systems, altering the orientation and the very identity of the individual. If this occurs, an individual not only becomes blind but ceases to behave as a visual being, offers no report of any change in inner state, is completely oblivious of his own visuality or lack of it. Such a condition, of total psychic blindness (known as Anton’s syndrome), may occur if there is massive damage, as from a stroke, to the visual parts of the brain. But it also seemed to occur, on occasion, with Virgil. At such times, indeed, he might talk of “seeing” while in fact appearing blind and showing no visual behavior whatever. One had to wonder whether the whole basis of visual perception and identity in Virgil was as yet so feeble that under conditions of overload or exhaustion he might go in and out of not merely physical blindness but a total Anton-like psychic blindness.
