The Spread of Agriculture: Quantitative Laws in Prehistory?

We review quantitative estimations of Neolithic spread rates in different regions of the world. The speed is about 1 km/year in most cases. This holds for the average rate of the spread of the Neolithic in Europe and the near East, rice in China and southeastern Asia, and the eastern Bantu expansion. A regularity in spread rates is thus clearly implied, which suggests a quantitative law in prehistory (first law or ‘1 km/year law’). However, there are exceptions. The Khoi-khoi herding expansion in Southern Africa and the southern Bantu expansion display rates of about 2 km/year, perhaps due to substantial cultural diffusion in addition to demic diffusion (second law). Along the Western Mediterranean, the spread rate was about 10 km/year, and a similarly fast spread rate has been also estimated in the Western Pacific (Austronesia). This suggests another quantitative law, valid for sea travel (third law). Another exception is Scandinavia, where the spread rate is only about 0.6 km/year, possibly due to lower reproduction rates. Ethnographic work has shown that human reproduction tends to decrease with increasing latitude. Thus, a similar trend could also exist in the spread rates of agriculture (fourth law).