The Mode and Tempo of the Initial Human Colonisation of Empty Landmasses: Sahul and the Americas Compared

The tempo and mode of the initial human colonisation of terra incognita has long been a controversial topic in archaeology. Two opposing models have been used to explain the earliest evidence for human occupation of 'Sahul' (a eustatically enlarged Pleistocene landmass that incorporated Tasmania and New Guinea): that people adapted quickly to new environments and hence spread rapidly over the region, or that they found adaptation to new conditions difficult and hence spread slowly, initially around the coast. The assumption that the rate of adaptation to new conditions determines the rate of spread underlies both hypotheses. We present here an alternative model of colonisation that reconsiders these issues. We suggest that initial human movement through Sahul would have been inherently fast. However, this rate of spread would not have been a consequence of rapid adaptation, but of maladapted subsistence strategies that resulted in inefficient extractive methods and hence low carrying capacities. Thus, we reverse the normal argument and posit that minimising adaptiveness, as long as human survival is possible, will maximise the rate of human spread over an empty landmass.