What is cumulative cultural evolution?

This is the final version. Available from The Royal Society via the DOI in this record.In recent years, the phenomenon of cumulative cultural evolution (CCE) has become the focus of major research interest in biology, psychology and anthropology. Some researchers argue that CCE is unique to humans and underlies our extraordinary evolutionary success as a species. Others claim to have found CCE in non-human species. Yet others remain sceptical that CCE is even important for explaining human behavioural diversity and complexity. These debates are hampered by multiple and often ambiguous definitions of CCE. Here, we review how researchers define, use and test CCE. We identify a core set of criteria for CCE which are both necessary and sufficient, and may be found in non-human species. We also identify a set of extended criteria that are observed in human CCE but not, to date, in other species. Different socio-cognitive mechanisms may underlie these different criteria. We reinterpret previous theoretical models and observational and experimental studies of both human and non-human species in light of these more fine-grained criteria. Finally, we discuss key issues surrounding information, fitness and cognition. We recommend that researchers are more explicit about what components of CCE they are testing and claiming to demonstrate.Economic and Social Research Council (ESRC

Examining the Causes and Consequences of Short-Term Behavioral Change during the Middle Stone Age at Sibudu, South Africa

Sibudu in KwaZulu-Natal (South Africa) with its rich and high-resolution archaeological sequence provides an ideal case study to examine the causes and consequences of short-term variation in the behavior of modern humans during the Middle Stone Age (MSA). We present the results from a technological analysis of 11 stratified lithic assemblages which overlie the Howiesons Poort deposits and all date to ~58 ka. Based on technological and typological attributes, we conducted inter-assemblage comparisons to characterize the nature and tempo of cultural change in successive occupations. This work identified considerable short-term variation with clear temporal trends throughout the sequence, demonstrating that knappers at Sibudu varied their technology over short time spans. The lithic assemblages can be grouped into three cohesive units which differ from each other in the procurement of raw materials, the frequency in the methods of core reduction, the kind of blanks produced, and in the nature of tools the inhabitants of Sibudu made and used. These groups of assemblages represent different strategies of lithic technology, which build upon each other in a gradual, cumulative manner. We also identify a clear pattern of development toward what we have previously defined as the Sibudan cultural taxonomic unit. Contextualizing these results on larger geographical scales shows that the later phase of the MSA during MIS 3 in KwaZulu-Natal and southern Africa is one of dynamic cultural change rather than of stasis or stagnation as has at times been claimed. In combination with environmental, subsistence and contextual information, our high-resolution data on lithic technology suggest that short-term behavioral variability at Sibudu can be best explained by changes in technological organization and socio-economic dynamics instead of environmental forcing