An intensification theory was developed in Australian archaeology in the early 1980s from a desire to make the study of Australian hunter-gatherers closer to theoretical developments in hunter-gatherer studies elsewhere. An apparent increase in the quantity and range of archaeological deposits was interpreted as demonstrating a combination of population increase and increased social complexity beginning 2-3000 years BP. Data were amassed in support of the theory but, with only one or two exceptions, they were not directly tested. Here we report on a series of studies that permit us to formulate a test for one aspect of the intensification theory. Chronologies constructed using OSL determinations of sediments are combined with the results of age determinations obtained from hearth charcoal to develop an 'envelope of time' for human occupation of the southeast margin of the Australian arid zone. The results indicate that the apparent increase in the quantity and range of archaeological materials in the late-Holocene record of western New South Wales reflects the age of the surface on which these materials rest. The apparent rapid increase in the archaeological record at the end of the Holocene reflects the culmination of erosion and deposition processes through time that have removed or covered archaeological records from earlier periods. A large number of radiocarbon determinations from hearths suggest that occupation was not continuous in the late Holocene, with occupation ceasing in this area during periods of climatic change. Analysis of surface stone artefact assemblages does not support the existence of semi-permanent camps or the congregation of large numbers of people. We conclude, therefore, that the intensification theory is incorrect at least in the areas of western New South Wales we have studied, and that human-environment interactions in the Holocene were much more complex than reflected by a simple summing of artefact and/or site data.