Our more gracile ancestors, the Cro-Magnon people, lived at the same time as the last of the Neanderthals, and there are many theories about what happened when the two subspecies interacted. Basically, we survived and the Neanderthals didn't ...

Why? Was it because we bashed them on the head more effectively than they bashed us? Did we outbreed them? Inbreed them? Squeeze them out into the 'edge country'? Crush them with superior extelligence? We'll put our own theory forward later in the book.

We don't subscribe to the 'rational' story of human evolution and development, the story that has named us so pretentiously Homo sapiens sapiens. Briefly, that story focuses on the nerve cells in our brains, and says that our brains got bigger and bigger until finally we evolved Albert Einstein. They did, and we did, and Albert was indeed pretty bright, but nonetheless the thrust of that story is nonsense, because it doesn't discuss why, or even how, our brains got bigger. It's like describing a cathedral by saying 'You start with a low wall of stones and as time passes you add more stones so that it gets higher and higher'. There's a lot more to a cathedral than that, as its builders would attest.

What actually happened is much more interesting, and you can see it going on all around you today. Let's look at it from the elf's viewpoint. We don't programme our children rationally, as we might set up a computer. Instead, we pour into their minds loads of irrational junk about sly foxes, wise owls, heroes and princes, magicians and genies, gods and demons, and bears that get stuck in rabbit-holes; we frighten them half to death with tales of terror, and they come to enjoy the fear. We beat them (not very much in the last few decades, but for thousands of years before that, for sure). We embed the teaching messages in long sagas, in priestly injunctions, and invented histories full of dramatic lessons; in children's stories that teach them by indirection.

Stand near a children's playground, and watch (these days, check with the local police station first, and in any case be sure to wear protective clothing). Peter and Iona Opie did just that, many years ago, and collected children's songs and games, some of them thousands of years old.

Culture passes through the whirlpool that is the child community without needing adults for its transmission: you will all remember Eeny-Meeny-Miny-Mo, or some other counting-out ritual.

There is a children's subculture that propagates itself without adult intervention, censorship, or indeed knowledge.

The Opies later collected, and began to explain to adults, the original nursery stories like Cinderella and Rumpelstiltskin. In late medieval times, Cinderella's slipper had been a fur one, not glass. And that was a euphemism, because (at least in the German version) the girls gave the prince their 'fur slipper' to try on ... The story came to us through the French, and in that language

'verre' can either be 'glass' or 'fur'. The Grimm brothers went for the hygienic alternative, saving parents the danger of embarrassing explanations.

Rumpelstiltskin was an interestingly sexual parable, too, a tale to programme the idea that female masturbation leads to sterility. Remember the tale? The miller's daughter, put in the barn to 'spin straw into gold', virginally sits on a little stick that becomes a little man ... The denouement has the little man, when his name is finally identified, jumping in to 'plug' the lady very intimately, and the assembled soldiers can't pull him out. In the modern bowdlerised version, this survives vestigially as the little man pushing his foot through the floor and not being able to pull it out, a total non sequitur. So none of those concerned, king, miller or queen, can procreate (the stolen first child has been killed by the soldiers), and it all ends in tears. If you doubt this interpretation, enjoy the indirection: 'What is his name? What is his name?' recurs in the story. What is his name? What is a stilt with a rumpled skin? Whoops. The name has an equivalent derivation in many languages, too. (In Discworld, Nanny Ogg claimed to have written a children's story called

'the Little Man Who Grew Too Big', but, then, Mrs Ogg always believed that a double entendre can mean only one thing.)

Why do we like stories? Why are their messages embedded so deeply in the human psyche?

Our brains have evolved to understand the world through patterns. These may be visual patterns, such as the tiger's stripes, or aural ones, like the howl of the coyote. Or smells. Or tastes. Or narratives. Stories are little mental models of the world, sequences of ideas strung like beads on a necklace. Each bead leads inexorably to the next bead; we know that the second little pig is going to get the chop: the world would not be working properly if it didn't.

We deal not just in patterns, but also in meta-patterns. Patterns of patterns. We watch archer-fish shooting down insects with jets of water, we enjoy the elephant using its nose to acquire doughnuts from zoo visitors (less these days, alas); we delight in the flight of house-martins

(there are fewer swallows to enjoy now) and the songs of garden-birds. We admire the weaver birds' nests, the silk moths' cocoons, the cheetahs' speed. All these things are characteristic of the creatures concerned. And what is characteristic of us? Stories. So, by the same token, we enjoy the stories of people. We are the storytelling chimpanzee, and we appreciate the meta-pattern involved in that.

When we became more social, collecting into groups of a hundred or more, probably with agriculture, more stories appeared in our extelligence, to guide us. We had to have rules for behaviour, ways to deal with the infirm and the handicapped, ways to divert violence. In early and present-day tribal societies, everything that is not forbidden is mandatory. Stories point to difficult situations, like the Good Samaritan story in the New Testament; the Prodigal Son, too, is instructive by indirection, like Rumpelstiltskin. To drive that home, here is a tale from the Nigerian Hausa tribe, Blind Man's Lantern.

A young man is coming home late from seeing his girlfriend in the next village; it is very dark under a starry sky and the path back to his own village is not easy to follow. He sees a lantern bobbing towards him, but when it gets closer he sees that it is carried by the Blind Man of his own village.

'Hey, Blind Man,' he says. 'You whose darkness is no darker than your noonday! What do you carry a lantern for?'

'It is not for my need I carry this lantern,' says the Blind Man. 'It is to keep off you fools with eyes!'

We, as a species, don't only specialise in storytelling. Just as with the other specialities above, our species has a few more oddities. Probably the most odd characteristic that our elvish observer would note is our obsessive regard for children. We not only care for our own children, which is entirely to be expected biologically, but for other people's children, too; indeed for other humankind's children (we often find foreign-looking children more attractive than our own); indeed for the children of all land vertebrate species. We coo over lambs, fawns, newly hatched turtles, even tadpoles!

Our sibling species, chimpanzees, are far more realistic. They too prefer baby animals. They prefer them for food, being more tender. (Humans also have a liking for lamb, calf, piglet, duckling ... We can coo over them and eat them.) After the kind of warfare now well documented between chimpanzee groups, the victors will kill and eat the young of the vanquished.

Male lions will kill the young of prides they take over, and eating the corpses is not unusual.

Many mammalian females will eat their young if both are starving, and will frequently 'reprocess'

the first litter in this manner anyway.