by Sam Kean
To see how this works, imagine Kish approaching an object while walking down the sidewalk. Click-click-click. He notices that his tongue clicks echo back from points near the ground, but that the echoes stop at about bellybutton height. A few steps on, the echoes bounce back up to chest height; a few more steps, and they drop again. That echo profile indicates a parked sedan. Similarly, telephone poles produce a tall and skinny profile. Sound quality also provides clues: whereas cars reflect noise sharply, bushes muffle it.
Kish can echolocate with enough agility to climb trees, dance, and ride his bike in heavy traffic. He also bought a twelve-by-twelve-foot cabin in Angeles National Forest, near his home, and then spent days alone there navigating trails and crossing streams on slippery rocks. Kish’s abandon has gotten him injured at times—smashed teeth, a broken heel. He also woke up in his cabin one night to find it on fire (bad chimney) and barely escaped. But he calls these frights “the price of freedom.” As he has written, “Running into a pole is a drag, but never being allowed to run into a pole is a disaster.”* It’s a sentiment James Holman would have hear-heared.
As a matter of fact, the feats of modern echolocators like Kish lend credence to Holman’s life story. On brain scans, echolocators show strong activity in the visual cortex while they’re listening to clicks. That’s probably because vision neurons, in helping us see things, also help us navigate the world around us. So they’d naturally be recruited for echolocation even if the raw input is auditory. After years of listening to the echoes from his cane, James Holman’s brain almost certainly remodeled itself in the same way. His auditory neurons and vision neurons had fired together so frequently and wired themselves together so intimately that translating sound maps into spatial maps became instinctual.
Unfortunately, Holman had fewer and fewer opportunities to exercise that instinct over the years. His health depended on travel, but as he began to request more and more leave time from the Naval Knights and began to travel farther and farther afield, and especially as he began to profit on his travels by publishing books—books full of exploits, such as climbing Mount Vesuvius, that seemed possible only for an able-bodied man—the wardens started seething. In retrospect, Holman probably had a psychosomatic illness: the depression that plagued his mind during his idle time in England also afflicted his body; conversely, traveling buoyed his spirits and relieved his physical pain. But with every trip the wardens of Windsor became more convinced that Holman was scamming them, and they began to forbid his travel, essentially sentencing him to house arrest. During these spells Holman appealed for help to every medical and political authority he could—a young Queen Victoria even got involved. But like Pharaoh of old, the wardens hardened their hearts and would not listen.
By 1855 Holman, in his midsixties, could barely manage a holiday to France anymore. And in truth, poor health was just one of several painful realities he had to face. When abroad, he kept wearing that staple of his traveling days, his naval uniform. But the coat and breeches had gone so out of fashion that even other sailors barely recognized him as a former officer. Worse, Holman’s celebrity with the general public had dimmed. He published his last travel book in 1832, and year by year he fell deeper into obscurity. On the rare occasions when a contemporary did mention him, it was usually in the past tense.
After turning seventy Holman stopped traveling altogether and rarely left his apartment. Friends worried about him, but it emerged that he’d actually thrown himself into one last journey, into his past, to write his autobiography. The long hours he spent straining on the Noctograph dictation machine depleted him further, but he pushed himself because he imagined the book would secure his legacy at last. He still wanted recognition that his journeys had meant something—and meant something beyond the fact that a blind man had undertaken them. He saw himself not as a sightless Marco Polo but as Marco Polo’s equal.
He completed the autobiography just before dying, in 1857. Sadly, no publishing house would take it, citing poor sales of his previous work. He left it to a literary executor, but that man in turn soon died, and within a few decades the book was lost to history.
Almost everything we know about Holman’s personal life, then, comes from his surviving books—and it’s not much. His favorite memories, his greatest disappointments, the names of his lovers, all of that remains unknown. He never even revealed how he first learned to echolocate. In fact, his travelogues spend amazingly little time discussing his blindness. Only one passage stands out for its frank discussion of his handicap and how it changed his worldview. In it, Holman was reminiscing about a few rendezvous from his past. Disarmingly, he admitted that he had no idea what his paramours looked like, or even whether they were homely. Moreover, he didn’t care: by abandoning the standards of the sighted world, he argued, he could tap into a more divine and more authentic beauty. Hearing a woman’s voice and feeling her caresses—and then filling in what was missing with his own fancy—gave him more pleasure than the mere sight of a woman ever had, he said, a pleasure beyond reality. “Are there any who imagine,” Holman asked, “that my loss of eyesight must necessarily deny me the enjoyment of such contemplations? How much more do I pity the mental darkness which could give rise to such an error.”
Holman was talking about love here; but in talking about desires and contemplations above and beyond what his eyes could strictly see, he was getting at something bigger—something bigger about himself, and about how all human beings perceive the world. With regard to sensory substitution, Paul Bach-y-Rita said, “We don’t see with the eyes. We see with the brain.” That sentiment is true in a broader sense as well. We all construct our reality to some degree, and if Holman augmented the scenes around him with his own imaginings, well, so do the rest of us. In other words, our neurons do more than simply record the world around us. As we’ll see next chapter, neuron circuits actually wire themselves together into still larger units, allowing our brains to reinterpret and remake what we see—infusing simple sights with layers of meaning and coloring mere perceptions with our own desires.
CHAPTER FOUR
Facing Brain Damage
Circuits of neurons in turn combine to form larger structures, like our sensory systems, which analyze information in advanced ways.
A man lies along a table, a mask of plaster covering his face. The mask looks normal—nose, ears, eyes, teeth, lips. But when it’s lifted, part of the soldier’s face beneath seems to lift off with it, leaving a crater in his flesh. Sitting up, the soldier gets his first deep breath since the plaster was painted on a half hour before. Assuming he has a nose, he might catch the scent of the flowers kept nearby to brighten the Paris studio. Assuming he has ears, he might hear the clatter of dominoes across the room, from other mutilated soldiers waiting for their turn on the table. Assuming he has a tongue, he might sip some vin blanc to revive himself. And assuming he has eyes, he might see dozens of other masks hanging on the wall—the befores and afters of fellow-mutilés who’d lost their faces in the Great War and hoped the masks would help them resume a normal life.
The woman making the masks had no medical qualifications, only artistic ones. Although American, Anna Coleman Ladd had lived most of her early life in Paris and studied sculpture there in the late 1800s; Auguste Rodin himself had advised her. Still, she lacked the élan to be famous. She ended up carving staid satyrs and nymphs for fountains and private gardens, and she all but gave up sculpture when she returned to Boston to marry a Harvard medical professor. They had an unconventionally independent marriage, but Ladd followed him to Europe in 1917 and later snuck into Paris. Inspired by a similar outfit in London, called the Tin Noses Shop, Ladd opened her prosthetic mask studio in 1918 in a fifth-floor walk-up in an ivied building. She populated the courtyard below with her old busts and sculptures—sculptures with classically beautiful faces that, however passé to the art world, must have stirred the hopes of the mutilés sneaking in for appointments beneath the cover of dawn or dusk.
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bsp; In one sense Ladd’s studio was conducting an artistic experiment in the tradition of Pygmalion—how realistic could realism get? At the same time she was conducting a psychological experiment—could she fool the brain into mistaking a mask for flesh? We humans often conflate our faces with our very selves. So by restoring a face torn in two by a bullet, she was attempting to restore a soldier’s identity. But she had no way of knowing whether other people—or the soldiers themselves—would accept the new faces as authentic.
Rebuilding a face wasn’t something doctors often worried about before 1914. A few soldiers and brawlers in history—most notably the emperor Justinian II and astronomer Tycho Brahe—had lost their noses in sword duels. Most received silver or copper replacements, and some surgeons did develop “natural” methods for replacing lost tissue. (One involved sewing the face to the crook of the elbow for a few weeks, until the arm skin adhered to the bridge of the nose and provided a cover flap.*) But the trench warfare of World War I produced orders of magnitude more facial casualties than ever before, the result of grenades, mortars, machine guns, and other methods of flinging metal at high velocities. Just before going down, many soldiers heard a crackle or whistle from a shell, then felt their facial bones explode. One man compared the feeling to “a glass bottle [dropped] into a porcelain bathtub.” Even dense jawbones might pulverize on contact, reduced to sand beneath the skin. And while metal helmets protected the brain, the helmet itself sometimes exploded into shrapnel when struck, gouging into eyes and ears. In all, tens of thousands of men (and a few women) woke up in a mudhole to find their noses torn off or tongues dangling. Some who lost eyelids slowly went blind as their corneas dried out. Other soldiers’ faces looked punched-in, like a Francis Bacon portrait.* Officers instructed men on watch duty that, when peeking at the enemy, they should put their heads and shoulders over the parapet, since snipers would aim for the body, a more agreeable place to be shot.
The apocalyptic Battle of the Somme in 1916—when newspapers had to print not just columns but whole pages of casualties—spurred the British military to open a hospital for facial injuries on a dairy farm in Kent. The head surgeon there, a part-time painter, had seen how slapdash plastic surgery could be: he’d once encountered a young man in a POW camp who had hair growing on his nose because someone had grafted skin from his scalp onto his face. Determined to end such practices, the surgeon emphasized the aesthetics of facial reconstruction, even demanding multiple surgeries to get things right. In all, the Kent hospital performed eleven thousand surgeries on five thousand British soldiers, and often tended them for months between operations. Some victims could swallow only liquids, so the farm also raised chickens and cows and fed the men an eggnog slurry for protein. As part of their rehabilitation, some soldiers tended the animals, while others learned trades such as making toys, repairing clocks, or hairdressing. Many of the men formed deep friendships with their fellow “gargoyles,” while others, being soldiers, also flirted with whatever women happened by. The boldest patients won their nurses as wives, and one exhilarated female visitor declared that “men without noses are very beautiful—like antique marbles.”
Not everyone was so broad-minded. The soldiers felt safe enough while in the wards to tease each other, even call each other ugly; but they always wore red ties and cornflower-blue jackets when visiting the nearest village, to warn people off from a distance. Shopkeepers wouldn’t sell the men liquor because some became unhinged when drunk, and outsiders dreaded eating with them because their food sometimes reappeared through extra holes when they chewed and swallowed. Some hospitals forbade the men mirrors, and when released from the safe cocoon of the facial ward, many patients killed themselves. Others found work in a new industry, enjoying long hours of dark solitude as cinema projectionists. And some of the direst cases, those that surgeons couldn’t salvage, sought out Ladd or her London counterpart.
To sculpt a face, Ladd used a man’s siblings or a preinjury photograph as models. A few hopeful soldiers brought in pictures of Rupert Brooke, a disarmingly handsome celebrity poet. Most, though, didn’t care about being gorgeous. They wanted only to become anonymous again. As a first step, Ladd plugged any holes in their faces with cotton and painted plaster onto whatever portion needed masking. She sculpted the new features with clay, then created the actual mask a few days later by electroplating thin layers of copper and silver onto the clay surface. She might affix some absorbent pads behind the façade if the man’s tear ducts or salivary glands leaked, but otherwise the six-ounce metal mask rested directly on the face, anchored by spectacles. She colored the masks with cream bath enamels to match skin tones, then made mustaches of metal foil, since real hair didn’t adhere. Each mask took a month to produce, cost around $18 ($250 today), and could be cleaned with potato juice. Ladd’s studio produced especially brilliant work. She painted gorgeous eyes, and left the slightest hint of blue in the cheeks to make them look freshly shaved. She also made foil mustaches so realistic that Frenchmen could twirl them (they much appreciated this), and even left their metal lips agape for cigarettes (ditto).
Plaster casts of soldiers’ faces. Notice the finished, wearable masks on the bottom. (Library of Congress)
Ladd and her assistants made hundreds of soldiers achingly happy. “The woman I love no longer finds me repulsive,” one lad wrote, “as she had a right to do.” One veteran wore his mask during his wedding, and many more were buried in theirs over the next few decades. But however grateful, many found the masks too uncomfortable for daily use. The face has inordinate numbers of nerve endings, and the masks sometimes rubbed scars raw. Worse, the masks didn’t function like real faces—didn’t chew, didn’t smile, didn’t kiss. Even visually, the masks sometimes didn’t cut it. The features didn’t age the way skin did. The enamel chipped or corroded. And electric lighting, increasingly popular, often exposed the Phantom of the Opera–like seam between façade and flesh.
In the end, then, Ladd fell short: however artistic, her masks couldn’t quite simulate the experience of seeing a real human face. As a result, the deeper, more psychological questions that her work raised—can the brain adjust to seeing a new face in the mirror? would that change someone’s sense of self?—remained unanswered. It would take another century of work to get at those questions. And answering them would require understanding not only how the brain analyzes faces but, even more fundamentally, understanding how the brain sees the world around us at all.
The twentieth century’s first major discovery about vision came about, once again, because of war. Russia had long coveted a warm-water port on the Pacific Ocean, so in 1904 the czar sent hundreds of thousands of troops to Manchuria and Korea to bully one away from the Japanese. These soldiers were armed with high-speed rifles whose tiny, quarter-inch bullets rocketed from the muzzle at fourteen hundred miles per hour. Fast enough to penetrate the skull but small enough to avoid messy shattering, these bullets made clean, precise wounds like worm tracks through an apple. Japanese soldiers who were shot through the back of the brain—through the vision centers, in the occipital lobe—often woke up to find themselves with tiny blind spots, as if they were wearing glasses spattered with black paint.
Tatsuji Inouye, a Japanese ophthalmologist, had the uncomfortable job of calculating how much of a pension these speckled-blind soldiers should receive, based on the percentage of vision lost. Inouye could have gotten away with merely showing them a few pictures and jotting down what details they could and couldn’t see. But he was that rare thing, an idealistic bureaucrat, and he saw that his work revealed something deeper.
By 1904 neuroscientists knew a little about how vision worked in the brain. They knew that everything to the left of your nose (called the left visual field) gets transmitted into the brain’s right hemisphere, and that everything to the right of the nose (the right visual field) gets transmitted into the left hemisphere.* Moreover, scientists knew that the occipital lobe was somehow involved with vision, since strokes back there
often blinded people. But strokes caused such messy, widespread damage that the inner workings of the lobe remained mysterious. Scorching Russian bullets, in contrast, produced focal lesions as they entered and exited the brain. Inouye realized that if he could chart each man’s specific brain damage, and match that damage to the part of the eye where a blind spot now appeared, he could basically produce a map of the occipital lobe—and thereby determine what sections of the brain analyzed each part of the visual field.
Before he got too far along with this work, Inouye stopped to examine a big assumption—that bullets followed a straight line through the brain. Perhaps they ricocheted around inside the skull, or got gummed up and followed a twisted path instead. So Inouye hunted down soldiers who’d been shot through the top of the head while lying on their stomachs. In this position the bullets ran parallel to their spinal cords. So in addition to a skull entry wound and a skull exit wound, most men also had, crucially, a third wound where the bullet left the skull and plugged them in the chest or shoulder. Inouye had the men re-create their postures the moment they’d been shot, and he found that all three wounds always described a straight line. Confident now that he hadn’t overlooked anything, Inouye began mapping the occipital lobe, especially what’s now called the primary visual cortex (PVC).
His most important finding was that our brains effectively magnify whatever we’re looking at, by dedicating more neurons to the center of the visual field. Part of the primary visual cortex lies on the surface of the brain, just below the bump on the back of the noggin, and part of it lies buried beneath the brain’s surface. It turns out that soldiers with black speckles in the center of their vision always had damage to surface patches, while men with peripheral speckles had damage to the subterranean stuff. The consistency of this correlation proved, as Inouye had hoped, that certain regions of the brain always controlled certain parts of the eye.