There are several restrictions in reconstructing the composition of prehistoric populations on the basis of the present evidence. First of all there is the question of representativeness of the human remains for the population at large. The demographic investigation is frustrated by the apparent different treatment of young children and infants, and especially by the archaeologically elusive above-ground treatment of the dead. Postdepositional processes like preservation circumstances have caused loss of bone material as well. The scattered bones, moreover, offer limited opportunities for sex and age diagnosis, so a large part of the groups of individuals concerned remains unspecified.
Demographic studies are often directed at the establishment of the growth rate of populations – were they stable, declining or growing – in spite of the fact that age distributions of skeletons are often biased. A rise in the percentage of subadults between 5 and 19 years from c. 20 to 30%, as based on skeletal evidence for 68 European Mesolithic and Neolithic populations, would indicate population growth for the early Neolithic period (Bocquet-Appel & Dubouloz 2004). Jackes et al. (2008) argue for a stable Mesolithic population and a growing Neolithic one based on the fertility parameters of the populations of among others Lepenski Vir and Vlasac in the Ðerdap/Iron Gates gorge in south-east Europe. In view of the general background the data at our disposal from the populations in the Lower Rhine Basin are presented in table 6 in reference to other European Mesolithic and Neolithic series. This table is condensed after Bocquet-Appel (2002) and adapted using data from Jackes et al. (2008) and our populations from the Lower Rhine Basin.
Generally the Neolithic skeletal series display a higher proportion of juveniles between 5-19 years (based on the table published by Bocquet-Appel 2002). The values presented in table 6 show a mean ratio for the immature individuals of 0.189 (sd = 0.061) for the Mesolithic and 2.214 (sd = 0.078) for the Neolithic groups. The series of Hardinxveld-Giessendam and Swifterbant/Urk show a low proportion of immatures, with values well below 0.2. This could be indicative of a declining population, but these cases probably display biased distributions. These data are therefore interpreted as not representative of the underlying groups, but they are a welcome basis for the (qualitative) assessment of the group composition. The pooled data for Ypenburg and Schipluiden on the other hand show a proportion of juveniles of 0.267, which is well above average in comparison with other Neolithic groups. The mortality for the age interval 0-4 years is considerable as well at c.21%. We can conclude that these data are representative for the population at large and tentatively indicate population growth.
Table 6 Demographic parameters of Mesolithic and Neolithic populations (data partly derived from Bocquet-Appel 2002).