IN THE late 1990s, investigations by journalist Peter Watson into the illegal trade in smuggled old masters and stolen antiquities led to a Channel 4 Dispatches documentary that shook the art world.

As a result, Mr Watson says, “various people went to jail”.

He himself joined the Institute for Archaeological Research at Cambridge University, where he continued his investigations into what he calls the ‘illegal traffic in antiquities.’ “I went all over the world looking at sites,” he says. “My travels took me, among other places, to Mexico, Guatemala, Peru, Chile and central Nicaragua.”

What he learned of ancient art and ancient beliefs during his travels fuelled a new interest – in the difference between the people of the New World (the Americas) and the people of the Old World – Europe and Asia.

The result was a book published last year – The Great Divide – which looks at how, over a period of thousands of years, two entirely separate populations of people grew up: populations which had no significant contact with each other until Columbus.

It’s a gripping story – of a trek by small groups of people 15,000 years ago from Siberia across the Bering land bridge to Alaska; of how the melting of the great glaciers at the end of the last ice age caused the land bridge to be flooded, so the people who had colonised the New World were cut off; of how they gradually migrated southwards to colonise the entire Americas, adapting over thousands of years to the new environment and conditions.

Above all, it’s a story about how much we are influenced by our environment, whether we realise it or not.

We like to think we shape the world around us. But in fact, to a very great extent, it shapes us, Mr Watson says.

“We learn to live in our environment, we adapt to our environment and its rhythms. We try to control them, and for a time we can; but ultimately we can’t.”

The evidence is there, in the different way human cultures developed in the Old World and in the New.

The early humans who colonised the Americas found themselves in a very different world to their ancestors. The territory they entered was strung out from north to south instead of east to west (as in Europe and Asia), so there were greater extremes of temperature and climate to deal with.

The Americas were much more prone to natural catastrophes – earthquakes, volcanoes, tornadoes and hurricanes – than much of the Old World. There were no animals that could be domesticated, other than the llamas of central America – and even these were no use as beasts of burden.

Even the staple foods available were different. Instead of the rice and wheat and barley of the Old World, the people who entered the New World subsisted on roots and tubers, such as potatoes, which grew in drier ground away from the coasts. There were also far more hallucinogenic plants in the Americas.

The result of all this? In the Old World, trade flourished along the temperate east-west trade corridors; ideas were exchanged; the use of domesticated animals and beasts of burden led to the development of technologies such as the wheel; and civilisation developed comparatively quickly.

In the New World, there was less trade between northern and southern regions; less exchange of ideas; the wheel was never invented; psychotropic drugs were widely used (as opposed to alcohol in the Old World); and civilisation developed more slowly.

Even the religions were different. Those that developed in the Old World were based on fertility, on the regular annual cycle of the seasons – hence the importance still of Easter, which welcomes the spring, in the Christian church.

In the New World, they were based on trying to appease the unpredictable gods which caused hurricanes, earthquakes and volcanoes: and often involved bloody sacrifices (including human sacrifices) in an attempt to placate the gods.

Different mindsets, resulting from different environments. So we’re not quite as in control of things as we like to think, you see.