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A semiotic approach to the evolution of symboling capacities during the late Pleistocene with implications for claims of modernity in early human groups

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This research uses Peircean Semiotics to model the evolution of symbolic behavior in the human lineage and the potential material correlates of this evolutionary process in the archaeological record. The

This research uses Peircean Semiotics to model the evolution of symbolic behavior in the human lineage and the potential material correlates of this evolutionary process in the archaeological record. The semiotic model states the capacity for symbolic behavior developed in two distinct stages. Emergent capacities are characterized by the sporadic use of non-symbolic and symbolic material culture that affects information exchange between individuals. Symbolic exchange will be rare. Mobilized capacities are defined by the constant use of non-symbolic and symbolic objects that affect both interpersonal and group-level information exchange. Symbolic behavior will be obligatory and widespread. The model was tested against the published archaeological record dating from ~200,000 years ago to the Pleistocene/Holocene boundary in three sub-regions of Africa and Eurasia. A number of Exploratory and Confirmatory Data Analysis techniques were used to identify patterning in artifacts through time consistent with model predictions. The results indicate Emergent symboling capacities were expressed as early as ~100,000 years ago in Southern Africa and the Levant. However, capacities do not appear fully Mobilized in these regions until ~17,000 years ago. Emergent symboling is not evident in the European record until ~42,000 years ago, but develops rapidly. The results also indicate both Anatomically Modern Humans and Neanderthals had the capacity for symbolic behavior, but expressed those capacities differently. Moreover, interactions between the two populations did not select for symbolic expression, nor did periodic aggregation within groups. The analysis ultimately situates the capacity for symbolic behavior in increased engagement with materiality and the ability to recognize material objects can be made meaningful– an ability that must have been shared with Anatomically Modern Humans’ and Neanderthals’ most recent common ancestor. Consequently, the results have significant implications for notions of ‘modernity’ and human uniqueness that drive human origins research. This work pioneers deductive approaches to cognitive evolution, and both strengths and weaknesses are discussed. In offering notable results and best practices, it effectively operationalizes the semiotic model as a viable analytical method for human origins research.

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  • 2016

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Abiotic and Biotic Drivers of Turnover and Community Assembly in African Mammals

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Climate and environmental forcing are widely accepted to be important drivers of evolutionary and ecological change in mammal communities over geologic time scales. This paradigm has been particularly influential in

Climate and environmental forcing are widely accepted to be important drivers of evolutionary and ecological change in mammal communities over geologic time scales. This paradigm has been particularly influential in studies of the eastern African late Cenozoic fossil record, in which aridification, increasing seasonality, and C4 grassland expansion are seen as having shaped the major patterns of human and faunal evolution. Despite the ubiquity of studies linking climate and environmental forcing to evolutionary and ecological shifts in the mammalian fossil record, many central components of this paradigm remain untested or poorly developed. To fill this gap, this dissertation employs biogeographical and macroecological analyses of present-day African mammal communities as a lens for understanding how abiotic change may have shaped community turnover and structure in the eastern African Plio-Pleistocene. Three dissertation papers address: 1) the role of ecological niche breadth in shaping divergent patterns of macroevolutionary turnover across clades; 2) the effect of climatic and environmental gradients on community assembly; 3) the relative influence of paleo- versus present-day climates in structuring contemporary patterns of community diversity. Results of these papers call into question many tenets of current theory, particularly: 1) that niche breadth differences (and, by extension, their influence on allopatric speciation) are important drivers of macroevolution, 2) that climate is more important than biotic interactions in community assembly, and 3) that communities today are in equilibrium with present-day climates. These findings highlight the need to critically reevaluate the role and scale-dependence of climate in mammal evolution and community ecology and to carefully consider potential time lags and disequilibrium dynamics in the fossil record.

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  • 2018

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Landscape variability in tool-use and edge damage formation in South African Middle Stone Age lithic sssemblages

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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

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.

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  • 2016