CAHO Seminar - Human Dispersal Seminar

We have a current PhD student from the Quantitative Anthropology Group, Applied Mathematics discussing 'long-distance dispersal and human population diffusion: why modelling the spread of populations in archaeology is harder than we think'

Diffusion processes are common in the human past. These range from the spread of language and cultural innovations, to gene flow, to the colonisation of uninhabited areas. Archaeology attempts to make inferences about past populations based on the impacts that their presence caused. An understanding of the processes that underlie population distribution and characteristics, then, is useful.

We are interested in modelling the spread of populations into new territories. In particular, it has been suggested that human dispersal is characterised by rare long-distance events, which cause challenges to traditional modelling methods (eg. the Fisher-Kolmogorov equation). Such a dispersal regime can theoretically lead to an accelerating wave of advance. We have designed a simple lattice model for population diffusion that can incorporate long-distance dispersal. Unlike other approaches, our model does not make assumptions of an infinite or very large population size, which is unrealistic in the human case and, we find, can lead to extremely misleading results. Using parameters derived from human dispersals, our simulations suggest that significant corrections to standard modelling techniques may be required to describe even a highly simplified version of human population diffusion. These sort of corrections are important both in terms of predicting past human distributions and when trying to understand the implications of archaeologically observed waves of advance. Our simulation suggest that long-distance dispersal can lead to elevated rates of diffusion, including accelerating waves, and patchy site distributions - patterns that are seen, for example, in the spread of Paleo-Indians through the Americas.

Keep an eye on our blog at http://cahoseminars.soton.ac.uk and follow us on Twitter https://twitter.com/CAHO_uk.