Bone idlers

Every nine months or so some archaeologist discovers that our oldest ancestors are even older than we had already believed. This week's news was that recently discovered stone tools were made nearly 300,000 years earlier than the oldest previous finds. Flakes of rock with chipped edges, used for chopping, and "pounded" pieces (like anvils), found in Ethiopia are something like 2.6 million years old.

This is depressing. It effectively extends by several hundred millennia the period in which our forefathers and mothers managed to avoid any technological innovation whatsoever. And there were already 2 million years in which they achieved very little indeed.

How on earth can this be? We are, after all, talking about a very, very long time. It is only 10,000 years since crops were first grown, 5,000 years since humans smelted metal, 60 since TV was invented, 124 months since The Independent was first published - such achievements in such a short period! Yet in 2 million years our forebears failed to get beyond stone chips. Even by accident. You might have thought that somewhere in those vast tracts of time, somebody falling off a mountain, and saved by her voluminous squirrel skins, would have passed on the secret of parachuting. But no. How come?

Were they just too busy? Hunting and gathering can be time-consuming; skinning a mammoth takes a lot of energy; grubbing around for roots, or blackberrying, are not conducive to watching carefully while Ug demonstrates gliding with two leaves and a long stick. But in that case, how come things ever changed?

Explanation two is that most humans, far from being the restless innovators of popular myth, are in fact deeply conservative. Having been tutored in a perfectly efficient flaking method which was good enough for their parents, why change? Anyone who doubts the joint power of nostalgia and inertia should consider this week's call for a return of cadet forces in schools, and the commissioning of a new royal yacht.

But it takes relatively few innovators to change life completely for everyone else. So enter Dr Steven Mithen, proponent of cognitive archaeology and author of the recently published Prehistory of the Mind. Dr Mithen's view is that, until a sudden explosion of intelligence - somewhere between 100,000 and 30,000 years ago - our ancestors were just too stupid. They had "modular intelligences", in which technical intelligence was separated from social intelligence (i.e. you could tie your shoe, if shown, but you couldn't understand knots). Then language itself became a vehicle for thought (before then, the best that humanoids could do was gossip - which is also, of course, the distinction between a tabloid and a broadsheet newspaper). Metaphor was loosed upon the world.

There are still a couple of problems that Dr Mithen's explanation fails to iron out. The first is how his theory deals with the flaked tools in the first place. Someone furry must have worked out the principles involved, and chipped that cobble. So why couldn't the descendants of that innovator repeat the trick, but with writing, or pop music?

The other difficulty is provided by the example of ancient Egypt. After the development (by about 2400BC) of building skills sophisticated enough to create the Pyramids, the Pharoahs and their subjects did sod-all for 2 millennia. Their religion did not change, their art did not change, their technology did not change, for 2,000 years. Whilst there may have been an improved formula for henna, or a slightly tastier recipe for baboon in crocodile sauce, there was no steam engine, spinning jenny, or that agricultural thing for lifting turnips that you always learned about at school. It was the kind of civilisation that makes Michael Portillo look like a mad progressive.

Personally, I blame the climate. The valley of the Nile is temperate and warm. Crops grow easily, lotuses wave in the breeze (I think), and the view is perfect. Why should the temple artist spend an extra hour trying out a new way of representing the ibis-headed god, Thoth, when he could paint an old Thoth in his sleep, and then get back to his kohl- eyed mistress by the banks of the great river? Isn't this why Isambard Kingdom Brunel was not a Fijian, nor Marconi a Sri Lankan? Rain-lashed, windswept, they had nothing better to do than to improve things.