ABSTRACT
Thirty years ago, Ammerman and Cavalli-Sforza (1971) presented an elegant and initially convincing model explaining the spread of Neolithic farmers from the Near East into Europe. They observed that the dates for fifty-three European sites with early occurrences of wheat or barley showed a pattern of radiation westward from a Near Eastern point of origin (taking Jericho, Çayönü, Ali Kosh, or Jarmo as the hypothetical starting point yielded the same result in each case). The rate of expansion averaged about 1 km per year. The “wave of advance” model that they applied to the radiocarbon and spatial data was explicitly derived from Fisher’s (1937) mathematical/genetic model of the spread of a beneficial allele through a population. It required no human motivation, intentionality, or agency:
It has been shown mathematically … that if such an increase in population coincides with a modest local migration activity, random in direction (comparable to a Brownian motion), a wave of population expansion will set in and progress at a constant radial rate. This is just what we have observed with the measured rate for the European data.
