Transition to agriculture triggered demographic growth followed by collapse
Researchers have used two sets of data from the period 6000 to 2000 BC to investigate the demographics of the transition to agriculture in Europe: data from cemeteries, and radiocarbon dates from 24 well-documented archaeological regions across Europe.
The juvenility index is the proportion of a population aged between 5 and 19 years old: in an increasing population, this is high; in a declining population it is low. Researchers obtained data from 212 cemeteries, weighting results by settlement size. They then considered the Summed Calibrated Radiocarbon Date Probability Distribution (SCDPD) of 8,032 radiocarbon dates, which can be used as a proxy for population density and indicate whether populations are rising or falling at a given time.
Both sets of data gave similar results. The transition from Mesolithic to Neolithic in each region was accompanied by a sharp increase in the population, but after a period of stability there was a decline. The cemetery data indicated a period of growth lasting for about 720 years, a period of stability lasting for just under 1,000 years, followed by a decline. The use of radiocarbon dates is less proven as a proxy, but because far more data is available it should provide higher resolution results. The radiocarbon dates indicated that the period of growth had lasted for 420 years before a decline set in, lasting for 840 years for a complete boom to bust cycle of 1,260 years. That the two sets of results are reasonably consistent confirms SCDPD as a valid demographic proxy.
1. Downey, S., Bocaege, E., Kerig, T., Edinborough, K. & Shennan, S., Correlation with Juvenility Index Supports Interpretation of the Summed Calibrated Radiocarbon Date Probability Distribution (SCDPD) as a Valid Demographic Proxy. PLoS One 9 (8), e105730 (2014).