Acheulean variability and hominin dispersals: a model-bound approach

Understanding the pattern of hominin dispersal is a fundamental component of Palaeolithic archaeology and palaeoanthropology. A widely held assumption is that bifacial handaxe (i.e. Acheulean or ‘Mode 2’) technologies evolved in Africa and dispersed into northern and western Eurasia via subsequent hominin migrations. To date, however, few formal tests of this hypothesis have been presented. Here, we use a combination of morphometrics, cultural transmission theory, and a dispersal model drawn from population genetics in order to test this hypothesis. The iterative founder effect (repeated bottlenecking) model is assumed to be supported if a significant inverse relationship is found between geographic distance from source along an estimated dispersal route and within-assemblage variance. The results of our analyses support the hypothesis that Acheulean technologies evolved in Africa and dispersed with migrating hominin populations into northern and western Eurasia under the assumptions of this iterative founder effect model. Based on our results we suggest that the occurrence of certain Mode 1 technologies such as those east of the Movius Line, and some assemblages assigned to the Clactonian of Britain, plausibly represent instances where effective population sizes in colonising populations dropped below levels where Mode 2 technologies could be maintained.     

The Clactonian Question: On the Interpretation of Core-and-Flake Assemblages in the British Lower Paleolithic

In recent years, the nature, significance, and validity of the British core-and-flake assemblage known as the Clactonian have come under close scrutiny. More traditional ideas, which see the Clactonian as the product of a distinct, non-handax-making technical tradition, are being challenged by notions of a single European knapping repertoire in which the proportion of handaxes varies according to factors such as activity facies, local raw material potential, and landscape use. Furthermore, recent technological studies which show a basic technological parity between the Acheulean and the Clactonian, including claims for rare atypical bifaces within the Clactonian, have been argued as eroding the very rationale for seeing the Clactonian as a separate entity. These challenges have gained widespread acceptance, despite a lack of empirical support in some cases, questionable conclusions, and hints of a widely ignored, yet intriguing chronological recurrence. A review of the empirical basis and interpretation of the Clactonian, in both recent years and the recent past, suggests that the Clactonian is in danger of being explained away, rather than explained.