24 Zeitschrift für Ethnologie 115 (1990) 
Review of previous explanations 
Cross-cultural studies on the topic can roughly be classified into three categories, ac- 
cording to the major causal force underlying their explanation. I will refer to them as 
the demographical, ecological, or evolutionary explanations. 
By “demographical” I mean those hypotheses conceptualizing scarcity as a densi- 
ty-dependent phenomenon. The relationship between population density and warfare 
has first been statistically examined by Ember (1982) in his critique of a previous work 
of Sillitoe (1977). For Sillitoe's sample of 28 societies in New Guinea, Ember comes to 
the conclusion that war is the result of landshortages, brought about by population 
pressure.” Ember (1982) could also demonstrate a significant relationship between 
food shortages (another measure for population pressure, which shall indicate that 
carrying capacity has been reached) and warfare for a world-wide sample of 15 so- 
cieties. In a later study with a world-wide sample of 70 cultures, however, this result 
turned out to be not significant (Ember and Ember 1984). 
Sometimes scarcity caused by natural, density-independent factors (like drought) 
is supposed to compel people to go to war. Such an *ecological" argument is presented 
by Ember and Ember (1984), who show (again for a sample of 70 societies) that food 
shortages, created by natural disasters, will cause external warfare. On the other hand, 
no relationship could be found between ecological factors such as the spatial distri- 
bution of resources and the presence of blood feuds within a society, an argument 
developed by Black-Michaud (1975) and tested by Fleising and Goldenberg (1987). 
Finally, one study takes an evolutionary perspective in seeing scarcity as a result of 
increasing technical and societal differentiation (Leavitt 1977). The evolution of so- 
cieties 1s expected to be related both to external and to internal war. For external war 
the argument is more or less identical to the demographical explanations. The reason- 
ing behind the explanations for internal war is, that the maldistribution of resources 
leads to interest conflicts within the society, which will be violently resolved. The four 
propositions are confirmed by the statistical tests (n — 132): as societies evolve, the fre- 
quency of external warfare, riots and civil wars increase, while the frequency of feuds, 
due to the diminishing importance of kinship in more modern societies, declines. 
The socio-ecological approach 
The main shortcoming of the three types of explanations is their unidimensionality. 
Scarcity 1s designed to be either ecological, demographical or distributional in origin. 
Hence, both the ecological and the demographical perspective neglect that resources 
can be unevenly distributed in society, while Leavitt's cross-cultural test of the evolu- 
tionary argument, contrary to the highly elaborated theoretical framework (see 
? But see Hanser (1985) for a critical discussion of the land-shortage hypothesis for New Guinea.