Increased sedentism has also been proposed as an explanation for this late phase of growth , and while a decrease in residential mobility has been proposed in the Atacama desert of northern Chile around 7 kyr BP coinciding with our observed population growth at 7055 yr BP, there also appears to be much regional heterogeneity in mobility and, for instance, there is little to no evidence of increased sedentism in large areas of the SAAD at this time, including Patagonia [50,82].
58% per generation (95% CI = 0.42–0.81) is not unusually high, and is instead broadly consistent with (indeed slightly lower than) the global estimates of 1% per generation (0.04% per year) for broadscale background Holocene population growth . Zahid et al. proposed that this background growth rate is a global phenomenon occurring irrespective of the local environment or subsistence strategy and is, therefore, intrinsic to our species, arguing that it is likely to be related to the global climate and/or endogenous biological factors.
While current SPD simulation methods provide a robust statistical framework to test a single null hypothesis, successfully rejecting the null offers the researcher little in the way of drawing an inference about true population dynamics, and this inferential vacuum is often filled with overinterpretation of peaks and troughs in SPDs. Furthermore, rejection of the simple exponential model of constant background growth has become so common that it is no longer tenable to use a classical hypothesis test that heavily favours this null. Instead, we argue that a model selection approach is more appropriate. By including the exponential in the model selection process, there is still the opportunity for this model to be selected, but unlike current simulation methods that can only reject (or fail to reject) an ‘assumed correct’ model, CPL modelling automatically provides a best explanation. Sigue leyendo