The Science of Discworld II - The Globe tsod-2

by Terry Pratchett

  This is why we can get the words of songs completely wrong and not realise it. The Guardian newspaper ran an amusing section on this habit, with examples such as 'kit-kat angel' for 'kickass angel' - bit of a generation gap there, which underlines how our perceptions are biased by our expectations. Ian recalls an Annie Lennox song that really went 'a garden overgrown with trees', but always sounded like 'I'm getting overgrown with fleas'.

  Holding a whole sentence, or a musical phrase, in our minds is what we do with time when we watch a TV or a cinema-screen. We run the frames together into a series of scenes, as well as making up all the spatial stuff that we're not actually looking at. The brain has so many tricks that its owner is not conscious of: as you sit there in the cinema your eyes are flicking from place to place on the screen, as they are doing while you read these words. But you turn off your perception as your eyes move, and re-jig your invented image so that your next retinal image is consistent with the previous version. That's why you get seasick or car-sick: if the outside image jumps about and isn't where you expect it to be, then that upsets your sense of balance.

  Now think about a piece of music. Isn't the construction of an extended present precisely the exercise that your brain 'wants' to do with a series of sounds, but without the complication of the meanings! As soon as you get used to the style of a particular kind of music, you can listen to it and grasp whole themes, tunes, developments, even though you're hearing only one note at a time. And the instrumentalist who is making the noise is doing the same kind of thing. His brain has expectations of what the music should sound like, and he fulfils those. To some extent.

  So it seems that our sense of music may be tied to a sense of an extended present. Some possible scientific evidence for this proposition has recently been found by Isabelle Peretz. In 1977 she identified a condition called 'congenital amusia'. This is not tone-deafness, but tune-deafness, and it should give us some insight into how normal people recognise tunes, by showing how that goes wrong. People with this condition cannot recognise tunes, not even 'Happy Birthday To You', and they have little or no sense of the difference between harmony and dissonance. There is nothing physically wrong with their hearing, however, and they were exposed to music as children. They are intelligent and have no history of mental illness. What seems to be wrong is that when it comes to music, they have no sense of an extended present. They cannot tap their feet in rhythm. They have no idea what a rhythm is. Their sense of timing is impaired. Mind you, so is their sense of pitch; they cannot distinguish sounds separated by an interval of two semitones -adjacent white keys on a piano. So the lack of an extended present is not the only problem. Congenital amusia is rare, and it affects males and females equally. Its sufferers have no difficulty with language, however, suggesting that the brain's music modules, or at least those affected by amusia, differ from its language modules.

  The same kind of interpretational step takes place in the visual arts, too. When you look at a painting -a Turner, say -it evokes in you a variety of emotions, perhaps nostalgia for a nearly forgotten holiday on a farm. That may give you a little burst of endorphins, chemicals in the brain that create a sense of well-being, but presumably you'd get much the same from a photograph or even a verbal description or a bit of pastoral poetry. The Turner painting does more than that, perhaps because it can be more sentimental, more idealised than a photo, however idyllic. It evokes the memory on a more personal level.

  What about other kinds of painting: the paper textures, the charcoal smear? Jack went to an art gallery, as an innocent in art appreciation, and tried the 'context' trick that any novice is always told to try. You're supposed to sit in front of the picture, and gaze at it, and kind of sink into it and feel how it relates to its surroundings. The result was instructive. When he paid attention to a small part of the canvas, he found that he could match the context that his brain had invented with the one that the artist had actually provided. The charcoal smear was particularly good for this: each part implied something of the pattern of the whole. However, there were intriguing differences from part to part. There were variations on the theme, as in music, superimposed on the brain's expectations. Jack's brain enjoyed comparing the picture that it was inventing with the progressively different one that the artist was forcing his brain to construct.

  Art goes back a long, long way, the further back we look, the more controversial the evidence is.

  The 'Dame a la Capuche', a 1.5-inch (3.5-cm) high statuette of a woman, exquisitely carved from mammoth-tusk ivory, is 25,000 years old. Some of the most elegant cave paintings, with simple, sweeping lines that depict horses, bison and the like, are found in the Grotte Chauvet in France, and in 1995 they were dated at 32,000 years old. The oldest art that undoubtedly is art is about

  38,000 years old: beads and pendants, found in Russia. And some beads made from ostrich egg shells in Kenya, which may be 40,000 years old.

  Further back, it all gets less certain. Ochre is a common pigment in rock drawings, and ochre

  'crayons' found in Australia are 60,000 years old. There is a lump of rock from the Golan Heights, whose natural crevices have been worn deeper, presumably by a human hand wielding another lump of rock. It bears a vague resemblance to a woman, and it is about 250,000 years old. But maybe it's just a lump of rock that a child idly scratched, and the shape is accidental.

  Imagine yourself in the cave as the artist paints bison on the wall. He (or she?) is creating a picture for your brain that differs progressively from the one that your brain expects: 'Now let's put a female woolly rhinoceros under him ...' There have been several 'artists' on television, doing precisely that trick. Rolf Harris was surprisingly good at drawing animal sketches before your very eyes. And they were iconic animals, too: sly fox and wise owl.

  There it all is, tied up in a bundle. Our perceptions are tied to our expectations, and we do not segregate sensations from each other, or from memories. They are all played off against each other in the seclusion of our minds. We absolutely do not program our brains with direct representations of the real world. From the beginning we're instructing our brains what to make of what we see, hear, smell and touch. We put spin on everything, and we anticipate, compare and contrast, construct lengths of time from successive instants, construct areas of picture from focused observation. We've been doing this, layer upon layer, taking more subtle nuances from conversation, from flirting glances, to 'Will she come to look like her mother does now?' assessments of the real world, all the time.

  That's what our brains do, and what edge people's brains don't.

  We suspect that Neanderthals didn't do that kind of thing much, either, because there's an alternative, and it's consistent with their cultural torpor. The alternative is to live in a world that you've set up to ensure that nothing is unexpected. All the events follow your expectations from previous events, so habit engenders security. Such a world is very stable, and that means it doesn't go anywhere much. Why try to leave the Garden of Eden? Gorillas don't.

  Tribal life could be like that for Homo sapiens, except that reality always intrudes, for instance those barbarians up on the hill. But Neanderthals, maybe, weren't afflicted by barbarians.

  Certainly, nothing seems to have provoked big changes in their lifestyles, even over tens of thousands of years. Art does provoke changes. It makes us look at the world in new ways. The elves like that, it gives new ways for them to terrify people. But Rincewind has seen further than the elves are capable of seeing, and he's worked out where art takes us. Where? You'll soon find out.

  25. PARAGON OF VEGETABLES

  The wine-dark sea lapped the distant shore. Nice country, Rincewind thought. A bit like Ephebe.

  Grapes, olives, honey and fish and sunshine.

  He turned back to his group of proto-actors. They were having difficulty grasping the idea.

  'Like the priests do in the temples?' said a man. 'Is that what you mean?'

  'Yes, but you can ... expand the ide
a,' said Rincewind. 'You can pretend to be the gods. Or anything else.'

  'Wouldn't we get into trouble?'

  'Not if you did it respectfully,' said Rincewind. 'And people would ... sort of see the gods. Seeing is believing, eh? Besides, children pretend to be other people all the time.'

  'But that is childish play,' said the man.

  'People might pay to see you,' said Rincewind. There was an immediate increase in interest.

  Human-shaped creatures were the same everywhere, Rincewind thought; if you got money for doing it, it had to be worth doing.

  'Just gods?' said a man.

  'Oh, no. Anything at all,' said Rincewind. 'Gods, demons, nymphs, shepherds—'

  'No, I couldn't do a shepherd,' said the possible thespian. 'I'm a carpenter. I don't know shepherding.'

  'But you know godding?'

  'Well, yeah, that's just ... thundering and shouting and that kind of thing. Being a decent shepherd takes years of work.'

  'You can't expect us to act like people,' said another man. 'That wouldn't be right.'

  'It's not respectful,' said a third man.

  Yes, we mustn't change things, thought Rincewind. The elves like that thinking. We mustn't change things, in case they end up different. Poor old Phocian ...

  'Well, can you do trees?' he said. He was vaguely aware that actors warmed up by pretending to be trees, amongst other things, and this presumably prevented wooden performances.

  'Trees are all right,' said a man. They're quite magical. But it wouldn't be respectful to our friend over there to ask us to be carpenters.' 'All right, then, trees. That's a start. Now, stretch out your

  —' There was a roll of thunder and a goddess appeared. Her hair was in golden ringlets, her white robe flapped in the breeze, and there was an owl on her shoulder. The men ran away.

  'Well, my little trickster,' said the goddess, 'and what are you teaching them?'

  Rincewind clapped a hand over one eye for a moment. 'That owl's stuffed,' he said. 'You can't fool me! No animals stay around elves without going mad!'

  The image of the goddess wavered as the Queen tried to maintain control, but glamour is susceptible to disbelief.

  'Oh, so brave?' she said, defaulting to her usual appearance. She turned at a creaking noise behind her. The Luggage had tiptoed up and opened its lid.

  'That doesn't frighten me,' she said.

  'Really? It frightens me,' said Rincewind. 'Anyway, I'm simply brushing up their acting skills.

  Absolutely no problem there, is there? You should love these people. There's dryads, nymphs, satyrs, centaurs, harpies and big giants with one eye, unless that's a joke about sex I haven't fully understood yet. They believe in all of them and none of them exist! Except possibly the one-eyed giant, that one's a bit of a puzzler.'

  'We have seen their performances,' said the Queen. 'They are not respectful of their gods.'

  'But seeing is believing, isn't it? And you must admit, they've got a lot of gods. Dozens.'

  He gave her a friendly smile, while hoping that she was keeping away from the local cities. They had a lot of temples in them, and shrines all over the place, but they also had a number of men who, while taking care to invoke the gods on every occasion, then appeared to expound ideas that didn't seem to have any place for gods in them, except as observers or decoration. But the actors liked playing gods ...

  'You're up to something,' said the Queen. 'Everywhere we look, you wizards are teaching people art. Why?'

  'Well, it's a rather drab planet,' said Rincewind.

  'Everywhere we go, they're telling stories,' said the Queen, still slowly circling. 'They're filling the sky with pictures, too.'

  'Oh, the constellations?' said Rincewind. 'They don't change, you know. Not like at home.

  Amazing. I tried getting one tribe to name that big one - you know, with what looks like a belt - I thought if they ended up calling it the Bursar, and that group of little stars off to the right became The Dried Frog Pills, it'd be a nice souvenir of our visit—'

  'You're frightened of me, aren't you,' said the Queen. 'All you wizards are frightened of women.'

  'Not me!' said Rincewind. 'Women are less likely to be armed!'

  'Yes you are,' the Queen insisted, moving closer. 'I wonder what your deepest desire is?'

  Not to be here right now would be favourite, Rincewind thought.

  'I wonder what I could give you,' said the Queen, caressing Rincewind's cheek.

  'Everyone knows that anything you get from the elves is gone by morning,' said Rincewind, trembling.

  'Yet many things are transient but pleasurable,' said the Queen, moving rather too close. 'What is it you want, Rincewind?'

  Rincewind shuddered. There was no way he could lie.

  'Potatoes,' he said.

  'Tuberous vegetables?' said the Queen, her brows knitting in puzzlement.

  'Well, yes. They've got them on one of the other continents, but they're not what I'd call spuds, and Ponder Stibbons says that if we left things as they were then by the time they've been brought over to this continent and bred up a bit it'd be the end of the world. So we thought we ought to ginger up the creativity level a bit.'

  'And that's it? That's why all you wizards are doing all this? Just to accelerate the breeding of a vegetable?

  'The vegetable, thank you,' said Rincewind. 'And you did ask. The potato, in my opinion, is the crown of the vegetable kingdom. There's roast potatoes, jacket potatoes, boiled potatoes, fried potatoes, curried potatoes—'

  'Just for a stupid tuber?'

  '— potato soup, potato salad, potato pancakes —'

  'All this for something that doesn't even see daylight!'

  '—mashed potato, chipped potato, stuffed potato—'

  The Queen slapped Rincewind's face. The Luggage bumped into the back of her legs. It wasn't entirely sure what was happening here. There were some things humans did that could be misinterpreted.

  'Do you not think I could give you something better than a potato?' she demanded.

  Rincewind looked puzzled.

  'Are we talking about a sour cream topping with chives?' he said.

  Something fell out of Rincewind's robe as he shifted uneasily. The Queen grabbed it.

  'What's this?' she said. 'There's writing all over it!'

  'It's just a script,' said Rincewind, still thinking about potatoes. 'A sort of story of a play,' he added. 'Nothing important at all. People going mad and getting killed, that sort of thing. And a glowworm.'

  'I recognise this script! It's from the future of this world. Why would you carry it around? What is so special? Hah, are there potatoes in it?'

  She leafed through the pages, as if she could read.

  'This must be important!' she snapped. And vanished.

  One solitary page slid down to the ground.

  Rincewind bent down and picked it up. Then he shouted hotly at the empty air: 'I suppose a packet of crisps is out of the question?'

  26. LIES TO CHIMPANZEES

  A central feature of human extelligence is the ability to infer what is going on in another person's mind, to guess what the world looks like from their point of view. Which is what Rincewind is trying to stop the Queen of the Elves from doing. We can't make such inferences with perfect accuracy; that would be telepathy, which is almost certainly impossible, because each brain is wired up differently and therefore represents the universe in its own special way. But we've evolved to be pretty good at guessing.

  This ability to get inside other people's heads has many beneficial consequences. One is that we recognise other people as people, not just automata. We recognise that they have a mind, that to them the universe seems just as real and vivid as it does to us, but that the vivid things they perceive may not be the same as those that we perceive. If intelligent beings are going to get along together without too much friction, it's important to realise that other members of your species have an internal mental universe, which controls their
actions in the same way that your own mind controls yours.

  When you can put yourself inside another person's mind, stories gain a new dimension. You can identify with a central character, and vicariously experience a different world. This is the appeal of fiction: you can captain a submarine, or spy on the enemy, from the safety and comfort of an armchair.

  Drama has the same appeal, too, but now there are real people to identify with; people who play a fictional role. Actors, actresses. And they rely even more on getting inside other people's minds, especially the minds of fictional characters. Macbeth. The Second Witch. Oberon.

  Titania. Bottom.

  How did this ability arise? As usual, it seems to have come about because of a complicity between the internal signal-processing abilities of the brain and the external pressures of culture.

  It arose through an evolutionary arms race, and the main weapon in that race was the lie.

  The story starts with the development of language. As the brains of proto-humans evolved, getting larger, there was room in them for more kinds of processing tasks to be carried out.

  Primitive grunts and gestures began to be organised into a relatively systematic code, able to represent aspects of the outside world that were important to the creatures concerned. A

  complicated concept like 'dog' became associated with a particular sound. Thanks to an agreed cultural convention, anyone who heard that sound responded to it with the mental image of a dog; it wasn't just a funny noise. If you try to listen to someone speaking a language that you know, focusing just on the noises that they are making and trying not to pick up the meaning of their words, you'll find that it's almost impossible. If they speak a language far removed from any that you know, however, their speech comes over as a meaningless gabble. It conveys less to you than a cat's miaow.

  In the brain are circuits of nerve cells that have learned to decode gabble into meaning. We've seen that as a child grows, it begins by babbling a random assortment of phonemes, the 'units' of sound that a human mouth and larynx can produce. Gradually the child's brain prunes the list down to those sounds that it hears from its parents and other adults. While it is doing that, the brain is destroying connections between nerve cells that seem to be obsolete. Quite a lot of the early mental development of an infant consists of chopping down a randomly connected, all- purpose brain, and pruning it into a brain that can detect the things that are considered important in the child's culture. If the child is not exposed to much linguistic stimulus in early childhood such as a 'feral' child brought up by animals -then they can't learn a language properly in later life. After about the age of ten, the brain's ability to learn language fades away.