Angela
Elite member
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See:Joaquim Fort, Maria Mercè Pareta, Lasse Sørensen
"Estimating the relative importance of demic and cultural diffusion in the spread of the Neolithic in Scandinavia"
http://rsif.royalsocietypublishing.org/content/15/148/20180597
"Abstract:
Using a database of early farming sites in Scandinavia, we estimate that the spread rate of the Neolithic was in the range 0.44–0.66 km yr−1. This is substantially slower (by about 50%) than the rate in continental Europe. We interpret this result in the framework of a new mathematical model that includes horizontal cultural transmission (acculturation), vertical cultural transmission (interbreeding) and demic diffusion (reproduction and dispersal of farmers). To parametrize the model, we estimate reproduction rates of early farmers using archaeological data (sum-calibrated probabilities for the dates of early Neolithic Scandinavian sites) and use them in a wave-of-advance model for the first time. Comparing the model with the archaeological data, we find that the percentage of the spread rate due to cultural diffusion is below 50% (except for very extreme parameter values, and even for them it is below 54%). This strongly suggests that the spread of the Neolithic in Scandinavia was driven mainly by demic diffusion. This conclusion, obtained from archaeological data, agrees qualitatively with the implications of ancient genetic data, but the latter are yet too few in Scandinavia to produce any quantitative percentage for the spread rate due to cultural diffusion. We also find that, on average, fewer than eight hunter–gatherers were incorporated in the Neolithic communities by each group of 10 pioneering farmers, via horizontal and/or vertical cultural transmission."
"In spite of the unquestionable importance of genome-wide studies, it should be stressed that they do not yield any quantitative estimation of the relative importance of demic and cultural diffusion on the spread rate of the Neolithic (note that the spread rate, or front speed, is the distance advanced by the Neolithic front per unit time, and is measured in kilometres per year). Indeed, genome-wide studies estimate fractions
,
, … ,
(due to N presumed populations) of the genetic drift f4 [10] (defined as a variance of allele frequencies [23]). But, there is no theory relating the fractions of genetic drift to the percentages of demic and cultural diffusion on the spread rate of the Neolithic wave of advance (and the same happens with other genetic methods, e.g. the fractions of the genome estimated by admixture analysis [24]). In other words, knowing, for example, the fraction
of the genetic Anatolian component of Scandinavian early farmers does not make it possible to know the effects (percentages) of demic and cultural diffusion on the Neolithic spread rate in Scandinavia. Therefore, as stressed previously [5], the relative importance of demic and cultural diffusion on the genetic pool and on the spread rate need not be the same. These two problems are related to each other, but only qualitatively, in the sense that if fewer hunter–gatherers were incorporated into the farming communities, then obviously the genetic Anatolian component
of Scandinavian early farmers would be higher and the cultural effect on the spread rate would be lower. But, they are not quantitatively related. For example, there is no proof that if the genetic Anatolian component
is above 50% then the cultural effect on the spread rate will be below 50%. Hence, a mainly demic process concerning the genetics is not necessarily a mainly demic process concerning archaeology (spread rate). These are two different problems, and they require different methods of analysis [5]. In this paper, we deal with the second problem by using archaeological data to estimate the spread rate of the Neolithic in Scandinavia. We also compare it with a new wave-of-advance model to estimate to what extent demic and/or cultural diffusion could have been responsible for it."
"The key issues that we address in the present paper are the following. Firstly, we estimate quantitatively the spread rate of the Neolithic in Scandinavia and find that it was substantially slower than in most of Europe. This is quite unexpected, given the widespread notion that the Neolithic spread in Scandinavia was extremely rapid [27,28]. Secondly, using a new mathematical wave-of-advance model, we try to understand the reason why the Neolithic spread rate in Scandinavia was so slow. Thirdly, we attempt to determine whether in Scandinavia (similarly to most of Europe [5]) demic diffusion had a more important effect than cultural diffusion on the Neolithic spread rate or not."
"Recently, it has been shown that a rapid warming took place in Scandinavia around 6000 cal yr BP, which improved environmental conditions and extended the growing season of domestic crops, leading at about the same time to a farmer population boom (Funnel Beaker culture) and the spread of the Neolithic northwards [30]. In this section, we estimate quantitatively the rate of this spread (in kilometres per year).
According to this linear fit (solid line), the Neolithic spread in Scandinavia with a rate in the range 0.44–0.66 km yr−1 with 95% CL. This is substantially slower (by about 50%) than the spread rate across the Near East and Europe, namely 0.9–1.0 km yr−1 (95% CL), which was previously obtained by the same method (namely, a linear regression of calibrated dates versus great-circle distances) [34]."
"Why was the Neolithic spread rate in Scandinavia so slow compared with most of Europe? Using a new mathematical wave-of-advance model, we have seen quantitatively that the lower reproductive rates (aN) of farmers in Scandinavia explain the slower spread rate of the Neolithic (figures 3a–7a), as compared with most of Europe. Additional, indirect support for this possibility comes from ethnographic data, according to which modern human populations at higher latitudes tend to have lower reproduction rates [40]"
Anyone know anything about the above???
"We have seen, by comparing the spread rate from the archaeological dates (horizontal rectangle in figures 3a–7a, obtained from figure 2) with the predictions of the model for five different dispersal kernels of pre-industrial famers (area between the two curves in figures 3a–7a), that the rate was dominated by demic diffusion, whereas cultural diffusion played a secondary role. This is clearly seen in figures 3b–7b, where the percentage of the cultural effect is always below 50% (the only exception is figure 7b, but even in this case the cultural effect is always below 54%, and is below 50% except for extreme parameter values)."
"Finally, we mention that some Early Neolithic parent–children pairs have been recently identified using genetic methods. However, for all pairs identified so far, the parent and the child are buried together [50]. If in the future geneticists could identify parent–children pairs such that the parent is buried in one place and the child in another place, it could be possible to estimate the dispersal kernel directly from archaeological (instead of ethnographic) data, and this would lead to more precise results. This improvement would be analogous to the fact that in this paper we have used archaeological (rather than ethnographic) data to estimate initial growth rates and used them, for the first time, in spread rate computations using a mathematical wave-of-advance model."
"
"Estimating the relative importance of demic and cultural diffusion in the spread of the Neolithic in Scandinavia"
http://rsif.royalsocietypublishing.org/content/15/148/20180597
"Abstract:
Using a database of early farming sites in Scandinavia, we estimate that the spread rate of the Neolithic was in the range 0.44–0.66 km yr−1. This is substantially slower (by about 50%) than the rate in continental Europe. We interpret this result in the framework of a new mathematical model that includes horizontal cultural transmission (acculturation), vertical cultural transmission (interbreeding) and demic diffusion (reproduction and dispersal of farmers). To parametrize the model, we estimate reproduction rates of early farmers using archaeological data (sum-calibrated probabilities for the dates of early Neolithic Scandinavian sites) and use them in a wave-of-advance model for the first time. Comparing the model with the archaeological data, we find that the percentage of the spread rate due to cultural diffusion is below 50% (except for very extreme parameter values, and even for them it is below 54%). This strongly suggests that the spread of the Neolithic in Scandinavia was driven mainly by demic diffusion. This conclusion, obtained from archaeological data, agrees qualitatively with the implications of ancient genetic data, but the latter are yet too few in Scandinavia to produce any quantitative percentage for the spread rate due to cultural diffusion. We also find that, on average, fewer than eight hunter–gatherers were incorporated in the Neolithic communities by each group of 10 pioneering farmers, via horizontal and/or vertical cultural transmission."
"In spite of the unquestionable importance of genome-wide studies, it should be stressed that they do not yield any quantitative estimation of the relative importance of demic and cultural diffusion on the spread rate of the Neolithic (note that the spread rate, or front speed, is the distance advanced by the Neolithic front per unit time, and is measured in kilometres per year). Indeed, genome-wide studies estimate fractions
"The key issues that we address in the present paper are the following. Firstly, we estimate quantitatively the spread rate of the Neolithic in Scandinavia and find that it was substantially slower than in most of Europe. This is quite unexpected, given the widespread notion that the Neolithic spread in Scandinavia was extremely rapid [27,28]. Secondly, using a new mathematical wave-of-advance model, we try to understand the reason why the Neolithic spread rate in Scandinavia was so slow. Thirdly, we attempt to determine whether in Scandinavia (similarly to most of Europe [5]) demic diffusion had a more important effect than cultural diffusion on the Neolithic spread rate or not."
"Recently, it has been shown that a rapid warming took place in Scandinavia around 6000 cal yr BP, which improved environmental conditions and extended the growing season of domestic crops, leading at about the same time to a farmer population boom (Funnel Beaker culture) and the spread of the Neolithic northwards [30]. In this section, we estimate quantitatively the rate of this spread (in kilometres per year).
According to this linear fit (solid line), the Neolithic spread in Scandinavia with a rate in the range 0.44–0.66 km yr−1 with 95% CL. This is substantially slower (by about 50%) than the spread rate across the Near East and Europe, namely 0.9–1.0 km yr−1 (95% CL), which was previously obtained by the same method (namely, a linear regression of calibrated dates versus great-circle distances) [34]."
"Why was the Neolithic spread rate in Scandinavia so slow compared with most of Europe? Using a new mathematical wave-of-advance model, we have seen quantitatively that the lower reproductive rates (aN) of farmers in Scandinavia explain the slower spread rate of the Neolithic (figures 3a–7a), as compared with most of Europe. Additional, indirect support for this possibility comes from ethnographic data, according to which modern human populations at higher latitudes tend to have lower reproduction rates [40]"
Anyone know anything about the above???
"We have seen, by comparing the spread rate from the archaeological dates (horizontal rectangle in figures 3a–7a, obtained from figure 2) with the predictions of the model for five different dispersal kernels of pre-industrial famers (area between the two curves in figures 3a–7a), that the rate was dominated by demic diffusion, whereas cultural diffusion played a secondary role. This is clearly seen in figures 3b–7b, where the percentage of the cultural effect is always below 50% (the only exception is figure 7b, but even in this case the cultural effect is always below 54%, and is below 50% except for extreme parameter values)."
"Finally, we mention that some Early Neolithic parent–children pairs have been recently identified using genetic methods. However, for all pairs identified so far, the parent and the child are buried together [50]. If in the future geneticists could identify parent–children pairs such that the parent is buried in one place and the child in another place, it could be possible to estimate the dispersal kernel directly from archaeological (instead of ethnographic) data, and this would lead to more precise results. This improvement would be analogous to the fact that in this paper we have used archaeological (rather than ethnographic) data to estimate initial growth rates and used them, for the first time, in spread rate computations using a mathematical wave-of-advance model."
"