The causes of prehistoric inter-group violence have been a subject of long-standing debate in archaeology, an- thropology, and other disciplines. Although population pressure has been considered as a major factor, due to the lack of available prehistoric data, few studies have directly examined its effect so far. In the present study, we used data on skeletal remains from the middle Yayoi period of the Japanese archipelago, where archaeologists argued that an increase of inter-group violence in this period could be explained (...) by a population-pressure hy- pothesis. We quantitatively examine the effect of population pressure on the frequency of inter-group violence by compiling an exhaustive data set. We collected demographic information based on burial jars (kamekan) and the frequency of violence based on the ratio of injured individuals. The results are consistent with the hypothesis, i. e., high population density can promote inter-group violence. (shrink)

The origins and consequences of warfare or largescale intergroup violence have been subject of long debate. Based on exhaustive surveys of skeletal remains for prehistoric hunter-gatherers and agriculturists in Japan, the present study examines levels of inferred violence and their implications for two different evolutionary models, i.e., parochial altruism model and subsistence model. The former assumes that frequent warfare played an important role in the evolution of altruism and the latter sees warfare as promoted by social changes induced by agriculture. (...) Our results are inconsistent with the parochial altruism model but consistent with the subsistence model, although the mortality values attributable to violence between hunter-gatherers and agriculturists were comparable. (shrink)

It has been commonly claimed that prehistoric warfare in Japan began in the Yayoi period. Population increases due to the introduction of agriculture from the Korean Peninsula to Japan resulted in the lack of land for cultivation and resources for the population, eventually triggering competition over land. This hypothesis has been supported by the demographic data inferred from historical changes in Kamekan, a burial system used especially in the Kyushu area in the Yayoi period. The present study aims to examine (...) the previous claim by using an expanded dataset of human skeletal remains and Kamekan. First, in order to quantify the intensity of warfare, we developed a database of injured individuals found in the middle phase of the Yayoi period in two large populations in the northern Kyushu area, the Fukuoka plain and the upperand middle-stream of the Homan River. Second, we collected Kamekan data from site reports published after 1990 and constructed a comprehensive database to infer the demography in these areas. Finally, we compared the frequency of injured individuals and the inferred demography. The results suggest that the frequency of injured individuals and the population increase tended to be higher at the upper- and middle-stream of the Homan River than on the Fukuoka plain. Different assumptions of the lifetime of each type of Kamekan can produce mixed results on the relationship between demography and the frequency of injured individuals. They were positively correlated under the traditional assumption of constant time intervals, while there was no correlation using time intervals based on carbon dating by the National Museum of Japanese History. Thus, our results are partially consistent with the previous claim that the population increase and the lack of land and resources due to the introduction of agriculture were causes of warfare in the northern Kyushu area in the middle phase of the Yayoi period. (shrink)

Whether man is predisposed to lethal violence, ranging from homicide to warfare, and how that may have impacted human evolution, are among the most controversial topics of debate on human evolution. Although recent studies on the evolution of warfare have been based on various archaeological and ethnographic data, they have reported mixed results: it is unclear whether or not warfare among prehistoric hunter – gatherers was common enough to be a component of human nature and a selective pressure for the (...) evolution of human behaviour. This paper reports the mortality attributable to violence, and the spatio-temporal pattern of violence thus shown among ancient hunter–gatherers using skeletal evidence in prehistoric Japan (the Jomon period: 13000 cal BC–800 cal BC). Our results suggest that the mortality due to violence was low and spatio-temporally highly restricted in the Jomon period, which implies that violence including warfare in prehistoric Japan was not common. (shrink)

Whether man is predisposed to lethal violence, ranging from homicide to warfare, and how that may have impacted human evolution, are among the most controversial topics of debate on human evolution. Although recent studies on the evolution of warfare have been based on various archaeological and ethnographic data, they have reported mixed results: it is unclear whether or notwarfare among prehistoric hunter–gathererswas common enough to be a component of human nature and a selective pressure for the evolution of human behaviour. (...) This paper reports the mortality attributable to violence, and the spatio-temporal pattern of violence thus shown among ancient hunter–gatherers using skeletal evidence in prehistoric Japan (the Jomon period: 13 000 cal BC–800 cal BC). Our results suggest that the mortality due to violence was low and spatio-temporally highly restricted in the Jomon period, which implies that violence including warfare in prehistoric Japan was not common. (shrink)