Sunday, November 13, 2005

Free trade may have finished off Neanderthals

Modern humans may have driven Neanderthals to extinction 30,000 years ago because Homo sapiens unlocked the secrets of free trade, say a group of US and Dutch economists. The theory could shed new light on the mysterious and sudden demise of the Neanderthals after over 260,000 years of healthy survival.

Anthropologists have considered a wide range of factors which may explain Neanderthal extinction, including biological, environmental and cultural causes. For example, one major study concluded that Neanderthals were less able to deal with plunging temperatures during the last glacial period.

Another possibility is that they were less able hunters as a result of poorer mental abilities, says Eric Delson, an anthropologist at Lehman College, City University of New York, US. But he adds that most theories are reliant on guesswork. Exactly how humans ousted Neanderthals remains a puzzle. “They were successful for such a long time,” he points out.

Jason Shogren, an economist at the University of Wyoming in Laramie, US, says part of the answer may lie in humans’ superior trading habits. Trading would have allowed the division of labour, freeing up skilled individuals, such as hunters, to focus on the tasks they are best at. Others, perhaps making tools or clothes or gathering food, would give the hunters resources in return for meat.

Largely unorganised

The idea that specialisation leads to greater success was first used in the 18th century to explain why some nations were wealthier than others. But this is the first time it has been applied to the Neanderthal extinction puzzle, says Shogren.

He cites archaeological evidence that suggests that humans, who joined Neanderthals in Europe about 40,000 years ago, specialised and traded both within and between regions. The evidence includes complex living quarters with different sections partitioned for different functions. Neanderthals, in contrast, lived in “largely unorganised” living spaces.

There is also evidence that the early humans, mainly one population called the Gravettians, imported materials. Ivory, stones, fossils, seashells and crafted tools were found dispersed through many regions. This greater pool of resources led to increased innovation, says Shogren.

Simulated circumstances

Shogren tested his theory with simulations of population growth. He even gave the Neanderthals, who were larger than Homo sapiens, a head start by assuming they were better hunters and individually brought home more meat - which may or may not be true.

But because humans were allowed to trade, in two of three similar simulations, they overcame this initial handicap and ousted the Neanderthals within 7000 years. In the third simulation, the two ended up co-existing.

“It’s an intriguing and novel idea,” says Delson. “But it requires stronger support.” He points out that the Gravettians in particular only emerged 28,000 years ago, while the last of the Neanderthals died about 29,000 years ago.

So the Gravettians could not have had very much influence in the extinction of the Neanderthals, he argues. “He also assumes that all they ate was meat, which of course is not true,” he adds.

The study will be published in an upcoming issue of the Journal of Economic Behaviour and Organization, co-authored by Erwin Bulte of Tilburg University in the Netherlands and Richard Horan at Michigan State University in East Lansing, US

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