Multiple Optima in Hoabinhian flaked stone artefact palaeoeconomics and palaeoecology at two archaeological sites in Northwest Thailand

High resolution analyses of flaked stone artefact technology coupled with palaeoecological reconstruction from oxygen isotope analyses of freshwater shells from two rockshelter in the highlands of Northwest Thailand are described. Previously undocumented scales of technological variation are observed in response to environmental variation across the prehistoric landscape and through time. Three models of human behavioural ecology are used to test predictions about how foragers adapted their stone artefact technology to variation in climatic conditions and proximity to stone resources. These models are found to be problematic and are modified by including multiple optima that reflect the specific ecological conditions under consideration.