Last updated June 14, 2018 at 11:53 am
New modelling settles a long-running debate. Sort of.
Too many people living off the fat of the land may have forced others to make hay while the sun shines, new modelling shows.
Research from a team led by Patrick Kavanagh of the Colorado State University in the US reveals that food surplus, rather than shortage, was the “common, global factor” in the development of agriculture – regardless of geography or historical period.
However, in a paper published in the journal Nature Human Behaviour, Kavanagh and his colleagues admit that the data cannot determine whether the domestication of plants and animals arose from within well-fed and secure communities, or in satellite communities pushed by population expansion onto less productive territories.
The rise of agriculture
To make their findings, the researchers compiled existing data in order to “hindcast” – an approach borrowed from oceanography that uses statistical calculation to determine probable past conditions.
The result was a model that encompassed environmental, geographical and cultural information for 220 foraging societies worldwide, spanning a period from 4000 to 21,000 years ago. The data, write the scientists, captures 77 per cent of the possible variation between the societies.
Using the results, it was possible to distinguish between the three main hypotheses advanced to explain the rise of agriculture.
The first idea suggests that it was an emergent property of improving environmental conditions and increasing population densities. The second contends the reverse – that deteriorating conditions forced the domestication of plant and animal species.
The third suggests that both the first and second ideas have merit, and that they applied in different instances during different periods.
Kavanagh and colleagues found that in every case “improving environmental conditions favoured higher local population densities during periods when domestication arose in every known agricultural origin centre”.
And while such a unanimous result might seem to bury the idea that agriculture was born of hardship, the fine-grain leaves the possibility wide open.
The researchers admit that their data and method are not powerful enough to make a crucial distinction. Did domestication begin inside coastal communities which gathered most of their food through foraging naturally occurring plants and animals? Or did it begin inside groups forced by increasing numbers away from the well-resourced heartland onto less fertile territory?
“Our results cannot support, or refute, the possible influence the outflow of people from hospitable locations to less ideal environments may have played,” they conclude.