The Rational Optimist (9 page)

It is rare for a predator to wipe out its prey altogether. In times of prey scarcity, erectus hominids, like other predators, had simply suffered local depopulation; that in turn would have saved the prey from extinction and the hominid numbers could recover in time. But these new people could innovate their way out of trouble; they could shift their niche, so they continued to thrive even as they extinguished their old prey. The last mammoth to be eaten on the Asian plain was probably thought a rare delicacy, a nice change from hare and gazelle stew. As they adjusted their tactics to catch smaller and faster prey, so the moderns developed better weapons, which in turn enabled them to survive at high densities, though at the expense of extinguishing more of the larger and slower-breeding prey. This pattern of shifting from big prey to small as the former were wiped out was characteristic of the new ex-Africans wherever they went. In Australia, almost all larger animal species, from diprotodons to giant kangaroos, became extinct soon after human beings arrived. In the Americas, human arrival coincided with a sudden extinction of the largest, slowest-breeding beasts. Much later in Madagascar and New Zealand mass extinctions of large animals also followed with human colonisation. (Incidentally, given the obsession of ‘show-off’ male hunters with catching the largest beasts with which to buy prestige in the tribe, it is worth reflecting that these mass extinctions owe something to sexual selection.)

Shall we trade?

Meanwhile, the stream of new technologies gathered pace. From around 45,000 years ago, the people of western Eurasia had progressively revolutionised their toolkit. They struck slim, sharp blades from cylindrical rock ‘cores’ – a trick that produces ten times as much cutting edge as the old way of working, but is far harder to pull off. By 34,000 years ago they were making bone points for spears, and by 26,000 they were making needles. Bone spear throwers, or atlatls – which greatly increase the velocity of javelins – appear by 18,000 years ago. Bows and arrows came soon afterwards. ‘Microburin’ borers were used for drilling the holes in needles and beads. Of course, stone tools would have been only a tiny tip of a technological iceberg, dominated by wood, which has long since rotted away. Antler, ivory and bone were just as important. String, made from plant fibres or leather, was almost certainly in use by then to catch fish and rabbits in nets or snares, and to make bags for carrying things in.

Nor was this virtuosity confined to practicalities. As well as bone and ivory, shells, fossil coral, steatite, jet, lignite, hematite, and pyrite were used to make ornaments and objects. A flute made from the bone of a vulture dates from 35,000 years ago at Hohle Fels and a tiny horse, carved from mammoth ivory and worn smooth by being used as a pendant, dates from 32,000 years ago at Vogelherd – both in Germany. By the time of Sungir, an open-air settlement from 28,000 years ago at a spot near the city of Vladimir, north-east of Moscow, people were being buried in clothes decorated with thousands of laboriously carved ivory beads, and even little wheel-shaped bone ornaments had appeared. At Mezherich, in what is now Ukraine, 18,000 years ago, jewellery made of shells from the Black Sea and amber from the Baltic implied trade over hundreds of miles.

This is in striking contrast to the Neanderthals, whose stone tools were virtually always made from raw material available within an hour’s walk of where the tool was used. To me this is a vital clue to why the Neanderthals were still making hand axes, while their African-origin competitors were making ever more types of tool. Without trade, innovation just does not happen. Exchange is to technology as sex is to evolution. It stimulates novelty. The remarkable thing about the moderns of west Asia is not so much the diversity of artefacts as the continual innovation. There is more invention between 80,000 and 20,000 years ago than there had been in the previous million. By today’s standards, it was very slow, but by the standards of
Homo erectus
it was lightning-fast. And the next ten millennia would see still more innovations: fish hooks, all sorts of implements, domesticated wolves, wheat, figs, sheep, money.

If you are not self-sufficient, but are working for other people, too, then it pays you to spend some time and effort to improve your technology and it pays you to specialise. Suppose, for example, that Adam lives in a grassy steppe where there are herds of reindeer in winter, but some days’ walk away is a coast, where there are fish in summer. He could spend winter hunting, then migrate to the coast to go fishing. But that way he would not only waste time travelling, and probably run a huge risk crossing the territory of another tribe. He would also have to get good at two quite different things.

If, instead, Adam sticks to hunting and then gives some dried meat and reindeer antlers – ideal for fashioning hooks from – to Oz, a coastal fisherman, in exchange for fish, he has achieved the goal of varying his diet in a less tiring or dangerous way. He has also bought an insurance policy. And Oz would be better off, because he could now catch (and spare) more fish. Next Adam realises that instead of giving Oz raw antlers, he can give him pieces of antler already fashioned into hooks. These are easier to transport and fetch a better price in fish. He got the idea when he once went to the trading point and noticed others selling antlers that had already been cut up into easy segments. One day, Oz asks him to make barbed hooks. And Adam suggests that Oz dries or smokes his fish so it lasts longer. Soon Oz brings shells, too, which Adam buys to make jewellery for a young woman he fancies. After a while, depressed by the low price fetched by hooks of even high quality, Adam hits on the idea of tanning some extra hides and bringing those to the trading point, too. Now he finds he is better at making hides than hooks, so he specialises in hides, giving his antlers to somebody from his own tribe in exchange for his hides. And so on, and on and on.

Fanciful, maybe. And no doubt wrong in all sorts of details. But the point is how easy it is to envisage both opportunities for trade among hunter-gatherers – meat for plants, fish for leather, wood for stone, antler for shells – and how easy it is for Stone Age people to discover mutual gains from trade and then to enhance that effect by further specialising and further dividing labour. The extraordinary thing about exchange is that it breeds: the more of it you do, the more of it you can do. And it calls forth innovation.

Which only raises another question: why did economic progress not accelerate towards an industrial revolution there and then? Why was progress so agonisingly slow for so many millennia? The answer, I suspect, lies in the fissile nature of human culture. Human beings have a deep capacity for isolationism, for fragmenting into groups that diverge from each other. In New Guinea, for instance, there are more than 800 languages, some spoken in areas just a few miles across yet as unintelligible to those on either side as French and English. There are still 7,000 languages spoken on earth and the people who speak each one are remarkably resistant to borrowing words, traditions, rituals or tastes from their neighbours. ‘Whereas vertical transmission of cultural traits goes largely unnoticed, horizontal transmission is far more likely to be regarded with suspicion or even indignation,’ say the evolutionary biologists Mark Pagel and Ruth Mace. ‘Cultures, it seems, like to shoot messengers.’ People do their utmost to cut themselves off from the free flow of ideas, technologies and habits, limiting the impact of specialisation and exchange.

Ricardo’s magic trick

Divisions of labour beyond the pair bond had probably been invented in the Upper Palaeolithic. Commenting on the ten thousand mammoth-ivory beads with which the clothing of two 28,000-year-old child corpses at Sungir in Russia were decorated, the anthropologist Ian Tattersall remarks: ‘It’s hardly probable that these young people had made their richly adorned vestments themselves. It’s much more likely that the sheer diversity of material production in their society was the result of the specialisation of individuals in different activities.’ The carvers of mammoth beads at Sungir, the painter of rhinoceroses at Chauvet, the striker of blades from rock cores, the maker of rabbit nets – perhaps these were all specialists, exchanging their labour for that of others. Perhaps there had been different roles within each band of human beings ever since the first emergence of modern people over 100,000 years ago.

It is such a human thing to do, and so obvious an explanation of the thing that needs explaining: the capacity for innovation. Specialisation would lead to expertise, and expertise would lead to improvement. Specialisation would also give the specialist an excuse for investing time in developing a laborious new technique. If you have a single fishing harpoon to make, there’s no sense in building a clever tool for making harpoons first, but if you have to make harpoons for five fishermen, then maybe there is sense and time-saving in first making the harpoon-making tool.

Specialisation would therefore create and increase the opportunities for gains from trade. The more Oz goes fishing, the better he gets at it, so the less time it takes him to catch each fish. The more hooks Adam the reindeer hunter makes, the better he gets at it, so the less time he takes to make each one. So it pays Oz to spend his day fishing and buy his hooks off Adam by giving him some fish. And it pays Adam to spend his day making hooks and get his fish delivered by Oz.

And, wonderfully, this is true even if Oz is better at hookmaking than Adam. Suppose Adam is a clumsy fool, who breaks half his hooks, but he is an even clumsier fisherman who cannot throw a line to save his life. Oz, meanwhile, is one of those irritating paragons who can whittle a bone hook with little trouble and always catches lots of fish. Yet it still pays Oz to get his hooks made for him by clumsy Adam. Why? Because with practise Adam has at least become better at making hooks than he is at fishing. It takes him three hours to make a hook, but four hours to catch a fish. Oz takes only an hour to catch a fish, but good as he is he still needs two hours to make a hook. So if each is self-sufficient, then Oz works for three hours (two to make the hook and one to catch the fish), while Adam works for seven hours (three to make the hook and four to catch a fish). If Oz catches two fish and swaps one for a hook from Adam, he only has to work two hours. If Adam makes two hooks and uses one to buy a fish from Oz, he only works for six hours. Both are better off than when they were self-sufficient. Both have gained an hour of leisure time.

I have done nothing here but retell, in Stone Age terms, the notion of comparative advantage as defined by the stockbroker David Ricardo in 1817. He used the example of England trading cloth for Portuguese wine, but the argument is the same:

Ricardo’s law has been called the only proposition in the whole of the social sciences that is both true and surprising. It is such an elegant idea that it is hard to believe that Palaeolithic people took so long to stumble upon it (or economists to define it); hard to understand why other species do not make use of it, too. It is rather baffling that we appear to be the only species that routinely exploits it. Of course, that is not quite right. Evolution has discovered Ricardo’s law and applied it to symbioses, such as the collaboration between alga and fungus that is a lichen plant or the collaboration between a cow and a bacterium in a rumen. Within species, too, there are clear gains from trade between cells of a body, polyps of a coral colony, ants of an ant colony, or mole-rats of a mole-rat colony. The great success of ants and termites – between them they may comprise one-third of all the animal biomass of land animals – is undoubtedly down to their division of labour. Insect social life is built not on increases in the complexity of individual behaviour, ‘but instead on specialization among individuals’. In the leafcutter ants of the Amazon rainforest, colonies may number millions, and workers grow into one of four distinct castes: minors, medias, majors and supermajor. In one species a supermajor (or soldier) may weigh the same as 500 minors.

But the big difference is that in every other species than human beings, the colonies consist of close relatives – even a city of a million ants is really just a huge family. Yet reproduction is the one task that people never delegate to a specialist, let alone a queen. What gave people the chance to exploit gains from trade, without waiting for Mother Nature’s tedious evolutionary crawl, was technology. Equipped with the right tool, a human being can become a soldier or a worker (maybe not a queen), and he can switch between the roles. The more you do something, the better you get at it. A band of hunter-gatherers in west Eurasia, 15,000 years ago, dividing labour not just by gender but by individual as well, would have been formidably more efficient than an undifferentiated band. Imagine, say, 100 people in the band. Some of them make tools, others make clothes, others hunt, others gather. One tiresome bloke insists on prancing around in a deer skull chanting spells and prayers, adding little to the general well-being, but then maybe he is in charge of the lunar calendar so he can tell people when the tides will be lowest for limpet-picking expeditions.

True, there is not much specialisation in modern hunter-gatherers. In the Kalahari or the Australian desert, apart from the gathering women, the hunting men and maybe the shaman, there are not too many distinct occupations in each band. But these are the simple societies left in the harsh habitats. In the relatively fertile lands of west Eurasia after 40,000 years ago, when bands of people were larger and lines of work were diverse, specialisation had probably grown up within each band. The Chauvet rhino painter was so good at his job (and yes, archaeologists think it was mainly one artist) that he must surely have had plenty of time off hunting duties to practise. The Sungir bead maker must have been working for a wage of some kind, because he cannot surely have had time to hunt for himself. Even Charles Darwin reckoned that ‘primeval man practised a division of labour; each man did not manufacture his own tools or rude pottery, but certain individuals appear to have devoted themselves to such work, no doubt receiving in exchange the produce of the chase.’