Radiocarbon evidence indicates that migrants introduced farming to Britain

Archaeologists disagree about how farming began in Britain. Some argue it was a result of indigenous groups adopting domesticates and cultigens via trade and exchange. Others contend it was the consequence of a migration of farmers from mainland Europe. To shed light on this debate, we used radiocarbon dates to estimate changes in population density between 8000 and 4000 cal BP. We found evidence for a marked and rapid increase in population density coincident with the appearance of cultigens around 6000 cal BP. We also found evidence that this increase occurred first in southern England and shortly afterwards in central Scotland. These findings are best explained by groups of farmers from the Continent independently colonizing England and Scotland, and therefore strongly support the migrant farmers hypothesis.     

A comment on Steele’s (2010) “radiocarbon dates as data: quantitative strategies for estimating colonization front speeds and event densities”

We show that Steele’s (2010) criticisms of Hamilton and Buchanan (2007) and Buchanan et al. (2008) do not hold water and demonstrate that his re-analyses of Hamilton and Buchanan’s (2007) and Buchanan et al'.s (2008) datasets are flawed. In the process, we highlight some important issues for researchers interested in using radiocarbon dates to reconstruct population movements and demography. Most notably, we explain why OLS regression is preferable to RMA regression when estimating diffusion velocity, and demonstrate that the summed probability distributions yielded by CalPal are more reliable as guides to past demographic change than those produced by Calib and OxCal.     

Bayesian radiocarbon models for the cultural transition during the Allerød in southern Scandinavia

During late Greenland Interstadial 1 (the Allerød chronozone), southern Scandinavia witnessed an abrupt cultural transition. This period marks the end of Late Magdalenian/Final Palaeolithic Federmessergruppen in the region, and the beginning of the Bromme culture. The latter is characterised by a restricted territorial range, loss of bow-arrow technology, and a general reduction in material culture complexity. Different hypotheses for the origin of the Bromme culture have been put forward, variously stressing local continuity or discontinuity. Different environmental and cultural factors have been suggested to force the observed changes, but crucially their precise timing remains elusive. Here, we review competing hypotheses for this cultural transition, and evaluate them using an audited regional database of the available ¹⁴C dates. We construct a series of Bayesian calibration models using the IntCal09 calibration curve to clarify timings of cultural continuity/discontinuity, probable duration of different techno-complexes, and relationships between environmental changes and material culture transitions. Our models suggest that the Bromme culture emerged late in the Allerød, and that the Laacher See-eruption most probably forced this cultural event horizon.     

Prehistoric population history: from the Late Glacial to the Late Neolithic in Central and Northern Europe

Summed probability distributions of radiocarbon dates are used to make inferences about the history of population fluctuations from the Mesolithic to the late Neolithic for three countries in central and northern Europe: Germany, Poland and Denmark. Two different methods of summing the dates produce very similar overall patterns. The validity of the aggregate patterns is supported by a number of regional studies based on other lines of evidence. The dramatic rise in population associated with the arrival of farming in these areas that is visible in the date distributions is not surprising. Much more unexpected are the fluctuations during the course of the Neolithic, and especially the indications of a drop in population at the end of the LBK early Neolithic that lasted for nearly a millennium. Possible reasons for the pattern are discussed.