Cultural diversity, population structure, and habitability during the eastern African Middle Stone Age

Although it was originally thought that our own species, Homo sapiens, evolved from a single population in Africa, patterns of diversity in fossil, archaeological, and genetic data now suggest a much more structured and reticulate process in response to varying environmental conditions through time. This thesis provides an investigation of environmentally driven population dynamics during the Middle Stone Age in a case study region of eastern Africa. A variety of complementary quantitative methods are applied to identify the impacts of habitat fluctuation on cultural diversity during this key period when our species first emerges in the record. Specifically, complex shape analyses of Middle Stone Age points, an (albeit imperfect) archaeological proxy for group identity, are used to test the predictions of group interaction from a climatically driven model of habitation that maps how conditions conducive to early human habitation fluctuated through time and space. This model delineates the changing areas of potential human occupation across Africa and the potential corridors between them, which are correlated with patterns of similarity and difference in the archaeological data. To collect the archaeological data during the COVID-19 pandemic, a scientifically robust collaborative data collection framework was developed to facilitate remote access to African museum collections, involving an equitable and cooperative approach to data generation. The results indicate that eastern African Middle Stone Age populations occupied diverse landscapes, with precipitation and access to water vital for determining site locations and corridors between them, as well as having significant influences over cultural diversity at both the assemblage and artefact-level. Almost half of the variance in point shape is found to be explained by spatial, temporal, and environmental autocorrelation, potentially suggesting stable cultural transmission throughout the region, though a large proportion of unexplained variance can be linked to stylistic variability between individual assemblages. The suitability of the environment that a population is situated within appears to condition point shape diversity to an extent, with interesting patterns of variance between assemblages observed considering the speculative dispersal routes between sites. Overall, complex modelling approaches, such as the one taken in this thesis, are needed to explain the ever-richer African record, will help develop new anthropological and archaeological theory and methods for understanding past population structure, and will advance our knowledge of the effects of climate change on human evolution.