Anatomies: A Cultural History of the Human Body (22 page)

It seems that our sense of sight has grown in importance during human evolution, and this growth may be at the expense of other senses. For example, we have many genes involved in processing smells, but they are underused in comparison with the relatively few we have dedicated to vision. As sight has become more important to us, it is the brain’s ability to process visual signals that has developed fastest. Our eyes themselves have not kept pace with our thirst for visual information, which may help to explain why, in a world where visual communication is increasingly important, so many of us nevertheless need to wear glasses.

In order to understand the extent to which vision is realized in the brain rather than the eye itself, and to which it overlaps with other sensory information, I pay a visit to the Cross-Modal Research Laboratory at the University of Oxford. The tiny laboratory resembles something between a toy store and a corner shop, stacked with odd gadgets and familiar food brands. Its director is Charles Spence, a professor of experimental psychology. He is wearing his trademark red trousers when I meet him, and speaks with an unnerving staccato delivery. The senses – the familiar five of sight, hearing, touch, taste and smell, though many more according to some beliefs – are usually considered in isolation, he explains. But we use them in concert. This leads to some very odd perceptions with disturbing implications. For example, Charles tells me, an interviewer is more likely to regard a job applicant as a serious candidate if the interviewer is holding a heavy file on his lap than if he is holding a lighter one. The weight of the file counts for more than what he sees and hears. ‘Never mind the quality, feel the width,’ it seems, is not just a desperate sales pitch, but an axiom in nature too.

Our unconscious mixing of sense signals can easily mislead us. It can also be exploited in order to alter our behaviour. Much of Charles’s work is for product manufacturers who can make good use of multisensory discoveries such as the fact that the sound you hear as your teeth crunch on a crisp, and even just the rustling of the packet, is a significant factor in your perception of its flavour. ‘We’re interested in the interaction of the senses, both at the level of the single cell and how it comes together in the brain. Can you “taste the weight”, for example? Or, how does the fragrance somebody is wearing affect your estimation of their age?’

Vision is surprisingly easy to fool, perhaps because our brains are so biased in favour of this sense. One famous experiment is known as the rubber-hand illusion. A subject’s hand is positioned out of their sight, while an artificial hand (a rubber glove will do) is placed in the line of sight where they might normally expect their real hand to be. The experimenter then touches both the invisible real hand and the visible artificial hand with a synchronized stroking action. After a while, the subject begins to feel that the fake hand is really their own. A cruel extension of the experiment involves bringing a hammer down on the artificial hand: the subject cannot help flinching. In these situations, the brain is prioritizing visual information over weaker signals sent from receptors under the skin of proprioception, our sense of our position in space. The hand must be a reasonable likeness for the trick to work: a left glove for a right hand will not produce the effect. However, since a bright yellow rubber glove works perfectly well, it seems that skin colour for once doesn’t matter.

A still more dramatic illustration comes from the psychologist Richard Gregory, who witnessed the recovery of a man who had been blind from birth until he was given a corneal graft. Gregory took the man to various stimulating venues in London, including the zoo and museums. At the Science Museum, he was shown a lathe, as he had always been interested in machinery. In its glass case, he was unable to recognize it. But once he had run his hands over it, he understood it fully. As Gregory tells it, ‘he stood back a little and opened his eyes and said: “Now that I’ve felt it I can see.”’ The moment explained why, on the journey to London, the subject had been entirely nonplussed by the sights streaming by the car window. The fact that he remained effectively blind to objects until he had touched them indicates that neural pathways concerned with vision had been taken over in his blindness by touch, and that his brain was only now beginning to rewire itself.

Understanding how our senses overlap in the brain can lead to better treatments for sensory loss. For example, therapeutic procedures using mirrors can help amputees who experience pain associated with their lost ‘phantom’ limb and stroke victims who have lost motor control on one side of the body by enabling them to compare sensory feedback obtained by proprioception with what they see in the mirror. One sense can even begin to replace another on a permanent basis. Blind people who use part of their brain normally dedicated to vision to interpret the letters of Braille sometimes find that the tactile sensitivity of the fingers is increased, giving them better spatial discrimination. In 1969, Paul Bach-y-Rita at the University of Wisconsin in Madison scaled up this idea to create prosthetic ‘eyes’ using arrays of vibrating pins acting like pixels to create crude images of scenes recorded by a camera. The device, called BrainPort, was initially designed as a vest to be strapped to the stomach, where the large expanse of skin would serve as a touch-sensitive screen. Later versions were miniaturized to fit on the surface of the tongue, which is much more touch-sensitive. Bach-y-Rita’s subsequent innovations show that other senses may be recreated in the same way, such as balance in subjects who have suffered damage to the part of the ear normally responsible for providing this sense. After a short period using the BrainPort, modified to detect tilt, some patients even found some restoration of ‘balance memory’ that lasted for several hours after the device was removed. People learn to use such equipment by a laborious process of conscious sensory translation, but as they become more familiar with it, the brain’s neural pathways adapt so that the substitute sense is experienced more like the sense that has been lost.

We are inherently multisensory beings. We see and hear together. We use our senses of smell and taste together. Combined sense signals often amount to more than the sum of their parts, and are more memorable. I am sure I would not recall a particular occasion when I was listening to the gods’ entry into Valhalla from Wagner’s opera
Das Rheingold
on the car radio if I had not been driving across the Severn bridge at that very moment, for example. It is only when he actually smells and tastes the famous madeleine that Marcel Proust’s memories of lost time are unleashed; the sight of it alone is not enough to do this. The converse is true, too: take away one sense, perhaps one we don’t even realize we are using at the time, and our perception is disproportionately impaired. A loss of sense of smell takes away much of the enjoyment of food, because so much of what we think of as taste is in fact linked to smell. Or, as Charles Spence’s tests have shown, it may be important that a warning signal on a car dashboard is delivered by visible and audible means together, such as a flashing light with an intermittent tone. The brain may miss either of these signals on its own, but has a much better chance of registering the correlated event.

I ask Charles about synaesthesia, an effect that has always intrigued me in which a signal in one sense also stimulates a brain response in another. A synaesthete might find that musical tones correspond to certain colours and textures, or that shapes conjure up tastes, for example. Some of my favourite composers and artists have claimed synaesthetic experience: Kandinsky, Hockney, Messaien, Sibelius and F. T. Marinetti, whose
Futurist Cookbook
includes recipes that require the diner to eat with one hand while stroking silk or sandpaper with the other, or to eat in a flight simulator so that the vibrations stimulate the taste-buds. One of the more persuasive claimants is the author Vladimir Nabokov, who lists the colours he associates with the letters of the alphabet in his autobiography,
Speak, Memory
. For him, each letter retains its distinct colour when placed next to others in a word, unless it produces a diphthong which happens to exist as a single letter in another language (such as happens with
sh
and
ch
and other combinations in the Russian alphabet of Nabokov’s early years); in this case, the single colour associated with the letter in the other language bizarrely stains the English letters that make up the equivalent phoneme.

Synaesthesia first attracted the attention of scientists in the late nineteenth century, when the multisensory experiences offered by the ‘total artworks’ of Wagner, Post-Impressionism, absinthe and opium doubtless encouraged them on their way. Little progress was made in understanding it, however, owing to the highly subjective nature of the phenomenon. It is only now being dusted off by neuroscientists, who are interested in what it might tell us about the brain’s ability to cross-wire the senses.

What is synaesthesia? Is it a condition, a delusion, an advantage or a curse? It is not listed in the most widely used psychiatric manual. It seems it is a neurological state of being, but not a neurological disorder, less like a condition and more like a cartoon hero’s ‘super power’. It’s not quite all wine and roses: ‘Synaesthetes may not be able to read a book because of the rush of extra information,’ Charles tells me. But they do enjoy the extra sensations and are better able to remember things as a result. ‘Synaesthetes wouldn’t take a pill to get rid of it.’ Synaesthetes come across rather like the members of an exclusive arty club. Certainly, there are many who clamour for admission. Conspicuous aesthetes such as Rimbaud and Baudelaire wrote works implying they had synaesthesia, for example, but scholars now believe that their experience of it was entirely vicarious, and they probably only picked up on the concept from medical reports. In modern tests, it is found in fact that women are more likely to experience synaesthesia than these male pseuds. Yet any of us might refer without affectation to a flower bed being a symphony of colour. We know there is music called the blues. Perhaps we are all latent synaesthetes.

Even blind people can have synaesthetic visual experiences, for example ‘seeing’ flashes of colour in response to aural signals such as numbers or letters being read out. It is thought that infants may possess neural pathways crossing over between the aural and the visual that are cut off in later life. One neuroscientist, Vilayanur Ramachandran, who has also worked on phantom limbs, describes the extraordinary case of one blind patient who began to notice that whenever he touched objects or read Braille his mind would conjure up flashes of light or vivid images (although not pictures of the item being touched). Such experiences suggest that neural pathways to the brain behind the damaged eye are somehow commandeered by these aural and tactile signals. Other blind people find that their hearing improves. It may not be their acuity to any sound that increases, but the ability specifically to process sounds that assist with spatial perception, which becomes such a challenge with the loss of sight. Individual cases such as these provide growing evidence that what scientists term the ‘neuroplasticity’ of the brain is directed towards restoring or enhancing its useful function when needed rather than merely shuffling the senses around at random.

The Stomach

It is not clear at what point the Very Reverend Doctor William Buckland’s project to eat everything tipped from earnest scientific enquiry to sheer silliness.

Buckland was a noted geologist, and the first professor in the subject at the University of Oxford. His masterpiece was
Vindiciae Geologiae
, a work which set out a new theory for the subject in which fossils predated Noah’s flood, but the Bible nonetheless remained literally true – a cunning piece of interpretation that relied on defining the ‘beginning’ in Genesis as some vague time after the formation of the earth but before the advent of man and other present-day species. He was the first to identify coprolites – fossilized dung – which provide our only direct evidence of what the dinosaurs ate. Against a background of suddenly rising grain prices, he wrote in favour of scientific agriculture, proper land drainage and irrigation, and allotments for the ‘labouring poor’. All this work secured Buckland’s reputation, and he rose in academia and the church to become the canon of Christ Church, Oxford, and later the dean of Westminster.

Buckland was not a man to be confined by establishment conventions, however. At the same time as pleasing everybody with his efforts to square the story of the Bible with the evidence of geology, he pursued a plan to taste the flesh of every animal. Though a notable scientist, he seems to have left no systematic record of his extended gustatory experiment; what information we have comes from anecdotes that continue to be passed down by Buckland’s descendants. It might be supposed that the project was an extension of his wish to identify new sources of food for the growing population, but in reality it seems to have been simply his own eccentric whim. He tried hedgehog, crocodile, panther, puppy and garden snail. The naturalist Richard Owen was entertained to roast ostrich, which he found tasted like ‘coarse turkey’. The critic John Ruskin much regretted missing another dinner at which was served ‘a delicate toast of mice’.

Certainly, Buckland was not afraid to shock his contemporaries. Visiting a cathedral overseas, his attention was drawn to ‘a martyr’s blood – dark spots on the pavement ever fresh and ineradicable’. His scepticism aroused, Buckland knelt and put his tongue to the spots, and was immediately able to report otherwise: ‘I can tell you what it is; it is bat’s urine.’ The account of one exceptional meal only emerged nearly fifty years after his death, when the writer Augustus Hare recollected being at a dinner with Lady Lyndhurst at her house in Nuneham near Oxford, where the heart of a French king (perhaps that of Louis XIV or Louis XVI; accounts differ) was said to lie preserved in a silver casket. As Hare tells it:

Dr. Buckland, whilst looking at it, exclaimed, ‘I have eaten many strange things, but have never eaten the heart of a king before,’ and, before anyone could hinder him, he had gobbled it up, and the precious relic was lost for ever. Dr. Buckland used to say that he had eaten his way through the whole animal creation, and that the worst thing was a mole – that was utterly horrible.

In a footnote, Hare adds: ‘Dr. Buckland afterwards told Lady Lyndhurst that there was one thing even worse than a mole, and that was a blue-bottle fly.’

Buckland’s unusual hobby did nothing to hinder his advance. Perhaps it even helped: as dean of Westminster in 1845, he used his position to improve the meals for boys at Westminster School – who knows what treats they were served. He died in 1856 aged seventy-three from an infection of the spine which spread to the brain, so we can presume at least that nothing he had eaten did him any lasting harm.

Of course, items such as ostrich and crocodile are now available in our fancier food emporia. My well-thumbed copy of
The Joy of Cooking
, the American classic, includes instructions for cooking porcupine, raccoon, bear (‘Bear cub will need about 2
½
hours’ cooking; for an older animal, allow 3
½
to 4 hours.’) and other road-kill recipes.

What does this unlucky bestiary say about the human stomach? Buckland seems mainly to have eaten whatever came his way partly out of a desire to amuse or shock. The reverend doctor certainly had no scriptural qualms concerning the prohibitions of Leviticus, since he doubtless ate numerous ‘abominable things’, including the bluebottle, which falls into the prohibited category of winged insects. If he did not try other unclean species such as hoopoe and hyrax, it is probably only because the opportunity never presented itself. Looking at his project more broadly, it seems reasonable to suppose that if he had put a fraction of the effort he put in to eating animals towards the evaluation of new vegetable sources of nutrition, he might have made a more practical contribution to the problems of feeding the world’s population.

The catalogue of animals that Buckland consumed is perhaps chiefly remarkable for reminding the rest of us how very few species generally make up our diet. The stomach is one of the simplest parts of the body to have earned the name of organ. As I am forced to acknowledge on seeing one for the first time in the dissection room, it is really just a bag, and as with any bag, you can put anything into it as long as it fits. Chevalier Jackson, a Philadelphia laryngologist, made a collection of the objects he retrieved from patients’ throats and stomachs 100 years ago. He amassed thousands of items, including keys, a padlock, nails and unclosed safety pins. The Gordon Museum, which houses the pathological anatomy collections of a number of the London teaching hospitals, exhibits a similarly extreme miscellany of objects swallowed down the years on purpose or by accident, including the bedsprings found in the stomach of a Brixton prison inmate who had been that desperate ‘to get out for a while’.

Humans are natural omnivores. Although we are not equipped with sharp teeth and claws and the speed to catch prey, we do have the big brains conferred on us by evolution which have enabled us to use tools and cunning to diversify our diet. Our baglike stomach can hold anything, and the five metres of intestines that lie downstream of it can make a good job of digesting most things. We can digest raw meat, but the discovery of fire gave us the ability to process meat far more effectively, and so to eat far more of it (more than is good for us). On the other hand, we can digest surprisingly little of what the vegetable kingdom has to offer, preferring as we do ripe fruit to grass and bark, since our stomachs lack the compartments that act like fermentation vats in true herbivores, breaking down the more fibrous organic matter. The disgust that we feel, therefore, when we are forced to consider a meal of bluebottle, or for that matter the human consumption of a human heart, is based entirely on culture rather than nature.

In perhaps the most famous of his essays, ‘On the Cannibals’, Michel de Montaigne wrote: ‘I think there is more barbarity . . . in lacerating by rack and torture a body still fully able to feel things . . . than in roasting him and eating him after his death.’ And indeed, human flesh, like most flesh, is nourishing to the omnivorous human body. What does it taste like? ‘Human flesh tastes like pork,’ according to Helen Tiffin, the author of an essay exploring humanity’s debt to the pigs that feed us and that now grow our replacement organs, too; ‘hence’, she continues, ‘the term “long pig” for human meat cuts, the “long” denoting the difference between the limb lengths of pig and human. Although there are few “first hand” accounts of the flavor of human flesh, its similarity in texture and taste to that of pork seems generally agreed upon.’ If the use of cadavers in medicine is acceptable utilitarian practice, Montaigne reasoned, then why isn’t their use for nourishment? In an age when physicians would taste a patient’s blood as an aid to diagnosis, and ground human skull (with or without ginger) was prescribed as a remedy for fits, cannibalistic practices might even be regarded as a legitimate medicinal use for the body.

Although tales of cannibalism continue to excite us as they once did Montaigne and Defoe and Melville, anthropologists had more or less set it aside as a topic for serious study. Alleged instances were historical or otherwise hard to confirm, and the sensationalism aroused was giving anthropology as a whole a bad name. However, interest was revived by an outbreak of the prion disease kuru in the mid twentieth century among the Fore people of the Papua New Guinea highlands. Prions are infectious agents based on proteins rather than on nucleic acids, as viruses and bacteria are. Prion diseases cause progressive loss of muscular coordination which is typically characterized by trembling, dementia and paralysis. The Papua New Guinea epidemic ultimately killed more than 2,500 people. The peculiar pattern of incidence of kuru was supposedly explained by a residual custom of cannibalism as the mode of transmission. Women would eat the brain and spinal cord of deceased relatives and become infected, as would children through contact with their mothers during ritual feasts. Men, who ate primarily the less infective muscle tissue, showed a lower infection rate.

But the American anthropologist William Arens is sceptical in regard to all claimed instances of ritual cannibalism, including even these ones where anthropological study is supplemented by medical scientific investigation. Arens notes that both medical and social scientists have tended to take unconfirmed stories of cannibalism as read, and that even professional anthropologist ‘witnesses’ may have been duped by seeing natives consuming what is in fact pig meat. (Melville teases the reader with just such a confusion in his South Seas novel
Typee
, where the mere lighting of a fire is enough to excite the fears of the two castaways at the centre of the story that they are for the pot. Then ‘some kind of steaming meat’ is brought out: ‘A baked baby, I dare say!’ They find it tastes ‘excellently good . . . very much like veal’. But their terror is revived when they recall that there are no cows on the island. ‘What a sensation in the abdominal region! Sure enough, where could the fiends incarnate have obtained meat?’ Finally, one of the men holds a lighted taper over the pot and to his great relief identifies ‘the mutilated remains of a juvenile porker’.) When the infectious protein or prion responsible for kuru was duly traced, the cannibalism route for transmission remained largely accepted, although in Arens’s view the evidence was still only ‘circumstantial’. How is it, he wonders, that cannibalism explains kuru seen among a remote New Guinean tribe, but is not suggested as a route for the transmission of the related Creutzfeldt-Jakob disease when it is found among developed societies? In general, controversy persists about the very existence of ritual cannibalism, with no solid evidence of contemporary practice and only unsubstantiated evidence of past practice. But if the practice is absent, the fear of it is apparently universal. More detached anthropologists have observed that very often the ‘primitive’ groups under investigation for supposed cannibalistic behaviour turn out to have their very own cannibalism myths about those who have come to study them!

From variety to quality – and quantity.

The potential for the human stomach to accommodate, if not everything, then at least an exciting variety of what nature has to offer leads us to the idea of the delicious. Why, when so much can be called food, are we so picky about what we eat? It is usually wise to turn to the French for advice in these matters, and none stands higher in this field than the author of the quasi-scientific masterpiece
The Physiology of Taste
, Jean Anthelme Brillat-Savarin, the only man, so far as I can discover, to enjoy the uniquely Gallic honour of having a cheese named after him. ‘To eat is a necessity,’ he observed. ‘To eat well is an art.’

Published in 1825, when Buckland was only on the hors d’œuvres of his grotesque eating experiment,
The Physiology of Taste
set the parameters for an emerging national cuisine in post-revolutionary France. It is a glorious mélange of recipes, history, humorous anecdotes, invented words, autobiography and food science, all prefaced by a number of ‘aphorisms of the professor’, which include the still-famous comments ‘Tell me what you eat, and I shall tell you what you are,’ and ‘The discovery of a new dish does more for human happiness than the discovery of a star.’ Brillat-Savarin, who was a lawyer and wrote large portions of the book in dull interludes while sitting in court as a judge, is accurate enough for his time on the workings of the human sense of taste, and why some of us are non-tasters while others are super-tasters, able perhaps to discern ‘the latitude under which a wine has ripened’ or ‘the special flavor of the leg upon which a sleeping pheasant rests his weight’. He explores the close relation of taste and smell, drawing much from an interview with a man whose tongue has been cut out as a punishment. He’s good, too, on the patent inadequacy of our convention of breaking down flavours into sweet, sour, bitter and salt. Modern classifications also admit the sensation of hotness imparted by chillies and an aromatic savoury sense,
umami
, from the Japanese, which Brillat seems to anticipate with his coinage of the term ‘osmazome’ to describe the depth of a good stock. But these few terms do not begin to compass the infinity of tastes, which would need ‘mountains of folio foolscap to define them, and unknown numerical characters for their classification’.

He has less to say, however, on how the gut digests food and the ways in which we extract from it energy, proteins, vitamins and minerals. For Brillat’s chief concern is our pleasure in food, as his book’s subtitle reveals:
Meditations on Transcendental Gastronomy
. In short, he wants us all to be gourmands. ‘Gourmandism is an impassioned, considered, and habitual preference for whatever pleases the taste,’ he writes – and not to be confused with gluttony, he adds hastily, for gourmandism ‘is the enemy of overindulgence’. He identifies some natural classes of gourmand: the clergy, writers, bankers, and also doctors, whom he nevertheless chides for their unpleasant-tasting medicines and austere dietary regimens. Gourmandism is for girls, too: ‘it is basically favorable to their beauty’. Gourmands make better marriages and live longer.