This study explores how early modern humans used stone tool technology to adapt to changing climates and coastlines in the Middle Stone Age of South Africa. The MSA is associated with the earliest fossil evidence for modern humans and complex cultural behaviors during a time period of dramatic climate change. Human culture allows for the creation, use, and transmission of technological knowledge that can evolve with changing environmental conditions. Understanding the interactions between technology and the environment is essential to illuminating the role of culture during the origin of our species. This study is focused on understanding ancient tool use from the study of lithic edge damage patterns at archaeological assemblages in southern Africa by using image-based quantitative methods for analyzing stone tools. An extensive experimental program using replicated stone tools provides the comparative linkages between the archaeological artifacts and the tasks for which they were used. MSA foragers structured their tool use and discard behaviors on the landscape in several ways – by using and discarding hunting tools more frequently in the field rather than in caves/rockshelters, but similarly in coastal and interior contexts. This study provides evidence that during a significant microlithic technological shift seen in southern Africa at ~75,000 years ago, new technologies were developed alongside rather than replacing existing technologies. These results are compared with aspects of the European archaeological record at this time to identify features of early human technological behavior that may be unique to the evolutionary history of our species.

This research addresses human adaptive decisions made at the Pleistocene-Holocene transition - the transition from the Last Glacial Maximum (LGM) to the climate regime in which humankind now lives - in the Mediterranean region of southeast Spain. Although on a geological time scale the Pleistocene-Holocene transition is the latest in a series of widespread environmental transformations due to glacial-interglacial cycles, it is the only one for which we have a record of the response by modern humans. Mediterranean Spain lay outside the refugium areas of late Pleistocene Europe, in which advancing ice sheets limited the land available for subsistence and caused relative demographic packing of hunter-gatherers. Therefore, the archaeological records of Mediterranean Spain contain more generally applicable states of the Pleistocene-Holocene transition, making it a natural laboratory for research on human adaptation to an environmental transformation. Foragers in Mediterranean Spain appear to have primarily adapted to macroclimatic change by extending their social networks to access new subsistence resources and by changing the mix of traditional relationships. Comparing faunal records from two cave sites near the Mediterranean coast with Geographic Information System (GIS) reconstructions of the coastal littoral plain from the LGM to the Holocene indicates the loss of the large ungulate species (mainly Bos primigenius and Equus) at one site coincided with the associated littoral disappearing due to sea level rise in the late Upper Paleolithic. Farther north, where portions of the associated littoral remained due to a larger initial mass and a more favorable topography, the species represented in the faunal record were constant through time. Social boundary defense definitions of territory require arranging social relationships in order to access even this lightly populated new hunting area on the interior plain. That the values of the least-cost-paths fit the parameters of two models equating varying degrees of social alliance with direct travel distances also helps support the hypothesis that foragers in Mediterranean Spain adapted to the consequences of macroclimatic change by extending their social networks to gain access to new subsistence resources Keeping these relationships stable and reliable was a mitigating factor in the mobility patterns of foragers during this period from direct travel to more distant down-the-line exchange. Information about changing conditions and new circumstances flowed along these same networks of social relationships. The consequences of climate-induced environmental changes are already a concern in the world, and human decisions in regard to future conditions are built upon past precedents. As the response to environmental risk centers on increasing the resilience of vulnerable smallholders, archaeology has an opportunity to apply its long-term perspective in the search for answers

Patterns of social conflict and cooperation among irrigation communities in southern Arizona from the Classic Hohokam through the Historic period (c. 1150 to c. 1900 CE) are analyzed. Archaeological survey of the Gila River Indian Community has yielded data that allow study of populations within the Hohokam core area (the lower Salt and middle Gila valleys). An etic design approach is adopted that analyzes tasks artifacts were intended to perform. This research is predicated on three hypotheses. It is suggested that (1) projectile point mass and performance exhibit directional change over time, and weight can therefore be used as a proxy for relative age within types, (2) stone points were designed differently for hunting and warfare, and (3) obsidian data can be employed to analyze socioeconomic interactions. This research identifies variation in the distribution of points that provides evidence for aspects of warfare, hunting, and the social mechanisms involved in procuring raw materials. Ethnographic observations and archaeological data suggest that flaked-stone points were designed (1) for hunting ungulates, or (2) for use against people. The distribution of points through time and space consequently provides evidence for conflict, and those aspects of subsistence in which they played a role. Points were commonly made from obsidian, a volcanic glass with properties that allow sources to be identified with precision. Patterns in obsidian procurement can therefore be employed to address socioeconomic interactions. By the 18th century, horticulturalists were present in only a few southern Arizona locations. Irrigation communities were more widely distributed during the Classic Period; the causes of the collapse of these communities and relationships between prehistoric and historic indigenes have been debated for centuries. Data presented here suggest that while changes in material culture occurred, multiple lines of evidence for cultural continuity from the prehistoric to Historic periods are present. The O'Odham creation story suggests that the population fluctuated over time, and archaeological evidence supports this observation. It appears that alterations in cultural practices and migrations occurred during intervals of low population density, and these fluctuations forced changes in political, economic, and social relationships along the middle Gila River