The Rational Optimist_ How Prosperity Evolves - Matt Ridley [22]
IAN MCEWAN
Saturday
One day a little less than 500,000 years ago, near what is now the village of Boxgrove in southern England, six or seven two-legged creatures sat down around the carcass of a wild horse they had just killed, probably with wooden spears. Each took up a block of flint and began to fashion it into a hand axe, skilfully using hammers of stone, bone or antler to chip off flakes until all that remained was a symmetrical, sharp-edged, teardrop-shaped object in size and thickness somewhere between an iPhone and a computer mouse. The debris they left that day is still there, leaving eerie shadows of their own legs as they sat and worked. You can tell that they were right-handed. Notice: each person made his own tools.
The hand axes they made to butcher that horse are fine examples of ‘Acheulean bifaces’. They are thin, symmetrical and razor-sharp along the edge, ideal for slicing through thick hide, severing the ligaments of joints and scraping meat from bones. The Acheulean biface is the stereotype of the Stone Age tool, the iconic flattened teardrop of the Palaeolithic. Because the species that made it has long been extinct we may never quite know how it was used. But one thing we do know. The creatures that made this thing were very content with it. By the time of the Boxgrove horse butchers, their ancestors had been making it to roughly the same design – hand-sized, sharp, double-sided, rounded – for about a million years. Their descendants would continue to make it for hundreds of thousands more years. That’s the same technology for more than a thousand millennia, ten thousand centuries, thirty thousand generations – an almost unimaginable length of time.
Not only that; they made roughly the same tools in south and north Africa and everywhere in between. They took the design with them to the Near East and to the far north-west of Europe (though not to East Asia) and still it did not change. A million years across three continents making the same one tool. During those million years their brains grew in size by about one-third. Here’s the startling thing. The bodies and brains of the creatures that made Acheulean hand axes changed faster than their tools.
To us, this is an absurd state of affairs. How could people have been so unimaginative, so slavish, as to make the same technology for so long? How could there have been so little innovation, regional variation, progress, or even regress?
Actually, this is not quite true, but the detailed truth reinforces the problem rather than resolves it. There is a single twitch of progress in biface hand-axe history: around 600,000 years ago, the design suddenly becomes a little more symmetrical. This coincides with the appearance of a new species of hominid which replaces its ancestor throughout Eurasia and Africa. Called Homo heidelbergensis, this creature has a much bigger brain, possibly 25 per cent bigger than late Homo erectus. Its brain was almost as big as a modern person’s. Yet not only did it go on making hand axes and very little else; the hand-axe design sank back into stagnation for another half a million years. We are used to thinking that technology and innovation go together, yet here is strong evidence that when human beings became tool makers, they did not experience anything remotely resembling cultural progress. They just did what they did very well. They did not change.
Bizarre as this may sound, in evolutionary terms it is quite normal. Most species do not change their habits during their few million years on earth or alter their lifestyle much in different parts of their range. Natural selection is a conservative force. It spends more of its time keeping species the same than changing them. Only towards the edge of its range, on an isolated island, or in a remote valley or on a lonely hill top, does natural selection occasionally cause part of a species to morph into something different. That different sport sometimes then spreads to conquer a broader ecological empire,