Laura Lewis | University of Oxford (original) (raw)
Papers by Laura Lewis
by Michael Petraglia, Huw Groucutt, Geoff Bailey, Eleanor Scerri, Ash Parton, Laura Lewis, James Blinkhorn, Paul S Breeze, Matthew Meredith-Williams, Mark Thomas, and Nicholas Drake
Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa i... more Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.
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The dispersal of Homo sapiens out of Africa has been extensively researched across several discip... more The dispersal of Homo sapiens out of Africa has been extensively researched across several disciplines. Here we review the evidence for spatial and temporal variability in lithic (stone tool) technologies relative to the predictions of two major hypotheses: 1) that a single successful dispersal occurred 60-50 thousand years ago (ka), marked by a trail of geometric/microlithic technologies, and 2) that multiple dispersals occurred, beginning much earlier (probably in Marine Isotope Stage [MIS] 5), associated with Middle Palaeolithic technology in its early phase. Our results show that Late Pleistocene geometric/ microlithic technologies exhibit significant temporal and regional differences between each other. These differences suggest independent, convergent origins for these technologies, which are likely to have been repeatedly re-invented. In contrast, we identify similarities between East African lithic technologies from MIS 8 onwards and Middle Palaeolithic assemblages as far east as India by MIS 5. That this constellation of technological features e particularly an emphasis on centripetal Levallois reduction reflecting inter- changeable preferential and recurrent methods, along with particular retouched forms such as points e transcends ecologies and raw material types suggests that it is unlikely to entirely reflect technological convergence (analogy). Our results indicate an early onset of multiple dispersals out of Africa. The hy- pothesis of an early onset to successful dispersal is entirely consistent with the possibility of further subsequent (post-MIS 5) dispersals out of Africa. Testing such hypotheses through quantified compar- ative lithic studies and interdisciplinary research is therefore likely to significantly advance under- standing of the earliest H. sapiens dispersals.
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The dispersal of Homo sapiens out of Africa has been extensively researched across several discip... more The dispersal of Homo sapiens out of Africa has been extensively researched across several disciplines. Here we review the evidence for spatial and temporal variability in lithic (stone tool) technologies relative to the predictions of two major hypotheses: 1) that a single successful dispersal occurred 60–50 thousand years ago (ka), marked by a trail of geometric/microlithic technologies, and 2) that multiple dispersals occurred, beginning much earlier (probably in Marine Isotope Stage [MIS] 5), associated with Middle Palaeolithic technology in its early phase. Our results show that Late Pleistocene geometric/microlithic technologies exhibit significant temporal and regional differences between each other. These differences suggest independent, convergent origins for these technologies, which are likely to have been repeatedly re-invented. In contrast, we identify similarities between East African lithic technologies from MIS 8 onwards and Middle Palaeolithic assemblages as far east as India by MIS 5. That this constellation of technological features – particularly an emphasis on centripetal Levallois reduction reflecting interchangeable preferential and recurrent methods, along with particular retouched forms such as points – transcends ecologies and raw material types suggests that it is unlikely to entirely reflect technological convergence (analogy). Our results indicate an early onset of multiple dispersals out of Africa. The hypothesis of an early onset to successful dispersal is entirely consistent with the possibility of further subsequent (post-MIS 5) dispersals out of Africa. Testing such hypotheses through quantified comparative lithic studies and interdisciplinary research is therefore likely to significantly advance understanding of the earliest H. sapiens dispersals.
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Here we conduct the first direct metric examination of two early regional manifestations of micro... more Here we conduct the first direct metric examination of two early regional manifestations of microlithic industries e the Howiesons Poort of southern Africa (c. 65-60 ka) and the Microlithic industry of South Asia (c. 38-12 ka). Inter-regional comparative analysis of microlithic industries is rare, but can contribute much to our understanding of technological systems in the past. Metric and qualitative variables were recorded on cores, debitage, and tools from Rose Cottage Cave and Umhlatuzana, South Africa, and Batadomba-lena, Sri Lanka, with the aim of conducting a first-stage technological assessment of the degree of technological homogeneity and diversity within these rich microlithic assemblages. The lithic methodology employed here uses the full range of lithic by products, as opposed to an approach based on tool typology alone. Preliminary analyses reveal areas of significant variation in inter-regional technological strategies. These include differences in blade production and blank selection, variation in microlith typology and morphology, disparate quartz reduction processes designed to produce similar tool types, varying degrees of utilisation of bipolar technology, and the existence of distinct reduction trajectories within sites. The examination of the diversity of microlithic assemblages through the use of detailed technological attribute analyses demonstrates a useful alternative methodology for the way we examine behavioural variability, and is a first step towards a thorough assessment of the place of microliths in models of human dispersals.
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The Toba super-eruption in northern Sumatra ∼74 ka was the largest eruption of the Quaternary per... more The Toba super-eruption in northern Sumatra ∼74 ka was the largest eruption of the Quaternary period. Terrestrial deposits of distal Toba tephra have been found across the Indian subcontinent, although few localities have been adequately described with respect to stratigraphy and sedimentary history. This study provides the first detailed description of the Ghoghara 1A ash section, Middle Son Valley, India. The sediment analyses provide insights into the depositional processes in the valley before and after the initial period of ash deposition. Grain size distribution analysis of sediments from Ghoghara 1A indicates that 4–5 cm of primary air-fall ash was laid down at the time of the Toba super-eruption. This study has implications concerning previous isotopic studies in the Middle Son Valley, concluding that reconstructions demonstrative of dramatic ecological changes are questionable.
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Books by Laura Lewis
Microlith production is a distinctive and significant stone tool technology. However, inter-regio... more Microlith production is a distinctive and significant stone tool technology. However, inter-regional comparative analyses of microlithic industries are rare, and tend to homogenise these industries by focussing analytical attention on retouched tool typologies alone. This volume provides the first demonstration and exploration of variability in two of the earliest microlithic industries in the world: the Howiesons Poort of southern Africa and the Late Palaeolithic of South Asia. Statistical analyses of the results of detailed attribute analyses reveal previously undocumented variability within and between sites, and over time, demonstrating that microlith production is not a homogenous technology. The results also provide evidence of the independent innovation of microlithic technology in the different regions. The implications of this variability for the long-standing debates concerning modern human behaviour and dispersals are explored. It is this behavioural and technological variability that is key to understanding our species.
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by Michael Petraglia, Huw Groucutt, Geoff Bailey, Eleanor Scerri, Ash Parton, Laura Lewis, James Blinkhorn, Paul S Breeze, Matthew Meredith-Williams, Mark Thomas, and Nicholas Drake
Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa i... more Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.
Bookmarks Related papers MentionsView impact
The dispersal of Homo sapiens out of Africa has been extensively researched across several discip... more The dispersal of Homo sapiens out of Africa has been extensively researched across several disciplines. Here we review the evidence for spatial and temporal variability in lithic (stone tool) technologies relative to the predictions of two major hypotheses: 1) that a single successful dispersal occurred 60-50 thousand years ago (ka), marked by a trail of geometric/microlithic technologies, and 2) that multiple dispersals occurred, beginning much earlier (probably in Marine Isotope Stage [MIS] 5), associated with Middle Palaeolithic technology in its early phase. Our results show that Late Pleistocene geometric/ microlithic technologies exhibit significant temporal and regional differences between each other. These differences suggest independent, convergent origins for these technologies, which are likely to have been repeatedly re-invented. In contrast, we identify similarities between East African lithic technologies from MIS 8 onwards and Middle Palaeolithic assemblages as far east as India by MIS 5. That this constellation of technological features e particularly an emphasis on centripetal Levallois reduction reflecting inter- changeable preferential and recurrent methods, along with particular retouched forms such as points e transcends ecologies and raw material types suggests that it is unlikely to entirely reflect technological convergence (analogy). Our results indicate an early onset of multiple dispersals out of Africa. The hy- pothesis of an early onset to successful dispersal is entirely consistent with the possibility of further subsequent (post-MIS 5) dispersals out of Africa. Testing such hypotheses through quantified compar- ative lithic studies and interdisciplinary research is therefore likely to significantly advance under- standing of the earliest H. sapiens dispersals.
Bookmarks Related papers MentionsView impact
The dispersal of Homo sapiens out of Africa has been extensively researched across several discip... more The dispersal of Homo sapiens out of Africa has been extensively researched across several disciplines. Here we review the evidence for spatial and temporal variability in lithic (stone tool) technologies relative to the predictions of two major hypotheses: 1) that a single successful dispersal occurred 60–50 thousand years ago (ka), marked by a trail of geometric/microlithic technologies, and 2) that multiple dispersals occurred, beginning much earlier (probably in Marine Isotope Stage [MIS] 5), associated with Middle Palaeolithic technology in its early phase. Our results show that Late Pleistocene geometric/microlithic technologies exhibit significant temporal and regional differences between each other. These differences suggest independent, convergent origins for these technologies, which are likely to have been repeatedly re-invented. In contrast, we identify similarities between East African lithic technologies from MIS 8 onwards and Middle Palaeolithic assemblages as far east as India by MIS 5. That this constellation of technological features – particularly an emphasis on centripetal Levallois reduction reflecting interchangeable preferential and recurrent methods, along with particular retouched forms such as points – transcends ecologies and raw material types suggests that it is unlikely to entirely reflect technological convergence (analogy). Our results indicate an early onset of multiple dispersals out of Africa. The hypothesis of an early onset to successful dispersal is entirely consistent with the possibility of further subsequent (post-MIS 5) dispersals out of Africa. Testing such hypotheses through quantified comparative lithic studies and interdisciplinary research is therefore likely to significantly advance understanding of the earliest H. sapiens dispersals.
Bookmarks Related papers MentionsView impact
Here we conduct the first direct metric examination of two early regional manifestations of micro... more Here we conduct the first direct metric examination of two early regional manifestations of microlithic industries e the Howiesons Poort of southern Africa (c. 65-60 ka) and the Microlithic industry of South Asia (c. 38-12 ka). Inter-regional comparative analysis of microlithic industries is rare, but can contribute much to our understanding of technological systems in the past. Metric and qualitative variables were recorded on cores, debitage, and tools from Rose Cottage Cave and Umhlatuzana, South Africa, and Batadomba-lena, Sri Lanka, with the aim of conducting a first-stage technological assessment of the degree of technological homogeneity and diversity within these rich microlithic assemblages. The lithic methodology employed here uses the full range of lithic by products, as opposed to an approach based on tool typology alone. Preliminary analyses reveal areas of significant variation in inter-regional technological strategies. These include differences in blade production and blank selection, variation in microlith typology and morphology, disparate quartz reduction processes designed to produce similar tool types, varying degrees of utilisation of bipolar technology, and the existence of distinct reduction trajectories within sites. The examination of the diversity of microlithic assemblages through the use of detailed technological attribute analyses demonstrates a useful alternative methodology for the way we examine behavioural variability, and is a first step towards a thorough assessment of the place of microliths in models of human dispersals.
Bookmarks Related papers MentionsView impact
The Toba super-eruption in northern Sumatra ∼74 ka was the largest eruption of the Quaternary per... more The Toba super-eruption in northern Sumatra ∼74 ka was the largest eruption of the Quaternary period. Terrestrial deposits of distal Toba tephra have been found across the Indian subcontinent, although few localities have been adequately described with respect to stratigraphy and sedimentary history. This study provides the first detailed description of the Ghoghara 1A ash section, Middle Son Valley, India. The sediment analyses provide insights into the depositional processes in the valley before and after the initial period of ash deposition. Grain size distribution analysis of sediments from Ghoghara 1A indicates that 4–5 cm of primary air-fall ash was laid down at the time of the Toba super-eruption. This study has implications concerning previous isotopic studies in the Middle Son Valley, concluding that reconstructions demonstrative of dramatic ecological changes are questionable.
Bookmarks Related papers MentionsView impact
Microlith production is a distinctive and significant stone tool technology. However, inter-regio... more Microlith production is a distinctive and significant stone tool technology. However, inter-regional comparative analyses of microlithic industries are rare, and tend to homogenise these industries by focussing analytical attention on retouched tool typologies alone. This volume provides the first demonstration and exploration of variability in two of the earliest microlithic industries in the world: the Howiesons Poort of southern Africa and the Late Palaeolithic of South Asia. Statistical analyses of the results of detailed attribute analyses reveal previously undocumented variability within and between sites, and over time, demonstrating that microlith production is not a homogenous technology. The results also provide evidence of the independent innovation of microlithic technology in the different regions. The implications of this variability for the long-standing debates concerning modern human behaviour and dispersals are explored. It is this behavioural and technological variability that is key to understanding our species.
Bookmarks Related papers MentionsView impact