Regional patterns of diachronic technological change in the Howiesons Poort of southern Africa.

Manuel Will,Nicholas J Conard,Justin W Adams

doi:10.1371/journal.pone.0239195

Manuel Will, Nicholas J Conard + Show 1 more

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https://doi.org/10.1371/journal.pone.0239195

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Abstract

The Howiesons Poort (HP) of southern Africa plays an important role in models on the early behavioral evolution of Homo sapiens. The HP is often portrayed as a coherent MSA industry characterized by early complex material culture. Recent work has emphasized parallel technological change through time across southern Africa potentially driven by ecological adaptations or demographic change. Here we examine patterns of diachronic variation within the HP and evaluate potential causal factors behind these changes. We test previous temporal assessments of the technocomplex at the local and regional level based on high-resolution quantitative data on HP lithic assemblages from Sibudu (KwaZulu-Natal) and comparisons with other southern African sites. At Sibudu, consistent unidirectional change in lithic technology characterizes the HP sequence. The results show a gradual reduction in typical HP markers such as the proportion of blades, backed pieces, and HP cores, as well as declining size of blades and backed artifacts. Quantitative comparisons with seven HP sites in South Africa suggest that lithic technology varies between regions over time instead of following similar changes. Concerning hypotheses of causal drivers, directional changes in lithic technology at Sibudu covary with shifting hunting patterns towards larger-sized bovids and a gradual opening of the vegetation. In contrast, variation in lithic technology shows little association with site use, mobility patterns or demographic expansions. Unlike at Sibudu, diachronic changes at other HP sites such as Diepkloof, Klasies River and Klipdrift appear to be associated with aspects of mobility, technological organization and site use. The regional diachronic patterns in the HP partly follow paleoclimatic zones, which could imply different ecological adaptations and distinct connection networks over time. Divergent and at times decoupled changes in lithic traits across sites precludes monocausal explanations for the entire HP, supporting more complex models for the observed technological trajectories.

Highlights

The archaeological period of the Middle Stone Age (MSA) is confined to the African continent and dates to ~300–40 ka
High-resolution stratigraphy and organic preservation allows us to examine some of these hypotheses in detail [see e.g. 84], and we extend this on a coarser scale to other Howiesons Poort (HP) sites in as much as the published data permit
To test for temporal variation in the HP sequence at Sibudu, we employ multiple levels of statistical analyses. While many of these statistical procedures have been applied to southern African MSA assemblages [e.g. 47, 48, 95], specific tests for assessing diachronic trends have not been performed for any HP sequence so far

Summary

Introduction

The archaeological period of the Middle Stone Age (MSA) is confined to the African continent and dates to ~300–40 ka. Conard [5, 11, 12] advances a model of “Mosaic Polycentric Modernity” which rejects the idea of a single source of cultural innovations in Africa. This scenario suggests multiple origins playing out on diverse timescales since the late Middle Pleistocene. Based on an updated review of the MSA record, Will et al [13] proposed divergent trajectories for cultural innovations and complex behaviors among different parts of Africa during the Middle and Late Pleistocene, characterized by non-linear timelines

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