The Ecological-Evolutionary Typology of Human Societies and the Evolution of Social Inequality

2.5A Preliminary Assessment

2.5.1Who Are These Societies?

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Table 2.1 shows the regions of the world where the different types of societies are located. Some of the geographical patterns may seem unexpected. So for example, a majority of HG societies (66.7%) are located in North America; most SH societies are located in the Insular Pacific zone (46.3%) or South America (25.9%); the vast majority of AH societies are in sub-Saharan Africa (73.8%); the bulk of AG societies are in the Circum-Mediterranean (44.4%) zone or in East-Eurasia (38.5%); a plurality of FI societies are in North America (45%); and, perhaps more obvious, most HE societies are in the Circum-Mediterranean zone.
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Table 2.2 shows how the different types of societies relate to a simpler classification using only the predominant source of subsistence (with gathering and hunting presented separately). It appears that FI and HE are straightforward, corresponding to the dominance of the corresponding activity. HG societies correspond to two modal subsistence categories, for Gathering (56.9%) and Hunting (23.0%); smaller entries for other categories of the subsistence variables reveals that some societies classified as HG also derive some resources from fishing and even farming. SH, AH, and AG societies are split among the subsistence categories corresponding to extensive and intensive agriculture, with a clear trend of increasing predominance of intensive agriculture from the SH to the AG type.

2.5.2Some Empirical Limitations of the Ecological-Evolutionary Typology

At this point one can already take stock of some of the features of the ecological-evolutionary typology applied to empirical data of the EA and SS.

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  The ecological-evolutionary typology is a categorical variable in which the categories are defined by establishing cutoff values for the percentages of utilization of various sources of subsistence, which are inherently continuous variables. Thus categorical assignments are partly arbitrary when a society depends on several sources of subsistence equally.
  
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  Because of ambiguity concerning the predominant source of subsistence, the typology is not exhaustive. In EA, for example, after excluding societies that cannot be classified because of missing data, there remains a residue of <> societies (<> of the original data set) that must be classified as Other because they do not have one predominant mode of subsistence. Lenski (1966) addresses the existence of societies of these societies, calling them hybrid societies, but does not describe them in any details. Generalizing about hybrid societies is inherently difficult, because this category is by definition heterogeneous.
  
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  The distinction between Simple and Advanced Agrarian is impractical (because most AG societies have acquired iron technology ).
  
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  Maritime societies cannot be distinguished on the basis of food producing activity, and therefore end up being classified within another type, often Agrarian.
  

2.5.3Plan of the Chapter

"Social inequality" is an elusive and multifaceted concept. In various sections of this paper I will examine how various dimensions of social inequality relate to the ecological-evolutionary typology, using the comparative date in EA or SS. I will show that, for some dimensions of inequality, the U-shaped relationship of inequality with technological development may have its nadir for AH societies rather than for AG societies. Other issues related to the measurement of social inequality, the meaning of polygyny in the context of stratification, and the rise of socially imposed monogamy will arise in the course of the analysis.

3Social Complexity

A number of characteristics of the evolution of stratification systems may be grouped under the heading of "social complexity". These include population density, the presence of social classes, the number of hierarchical level, and the degree of specialization. We examine how these variables relate to the ecological-evolutionary typology here.

3.1Population Density

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A more productive subsistence technology allows for the support of a larger population. Thus, more productive technology should correspond by and large to a greater population density. Table 3.1 shows that density varies markedly by type of society. Scanning down the last column corresponding to the highest density category (more than 100 persons per square mile), it appears that a density of more than 100 persons per square mile is achieved by 0% of HG societies, 8.6% of SH societies, 30% of AH societies, and 61.3% of AG societies; the gradient in relative productivity is unmistakable here. Such high density is maintained by 18.2% of FI societies, but by none of the HE societies. Herding presumably necessitates larger expanses of territory.

3.2Class Stratification Among Freemen

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Table 3.2 is based on a variable in the EA that indicates the presence of different types of stratification systems, such as hereditary aristocracy or social classes proper. These categories are not unambiguously ordinal so I recoded the variable into two categories denoting the absence (0) or presence (1) of class stratification among freemen. There is an unambiguous pattern of monotonically increasing likelihood of stratification as one goes up technology levels in the sequence HG (21.8%), SH (41.8%), AH (62.3%), and AG (85.7%). Class stratification is present in 51.9% of FI societies, a level between that of SH and AH societies. HE societies have high levels (79%), close to that of AG. As HE societies are usually not as productive as AG ones, the high proportion of HE with class stratification may be due in part to defense-related imperative in the HE lifestyle, in addition to a productivity effect.

3.3Jurisdictional Levels Beyond Local Community

One of the best indicators of the vertical complexity of a society is the number of hierarchical levels in which a society is embedded beyond the local community. (Betzig 1986 calls this variable simply "hierarchy".) This variable is also closely parallel to classical polity-oriented classification of societies such as those of Service (1962, 1975) and Fried (1967) (see also Diamond 1999:268-269).
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Table 3.3 shows how type of society within the ecological-evolutionary typology is related to the 5 levels of this variable, between 1 (no jurisdictional level beyond local community) to 5 (4 levels or large state). Looking first at the column corresponding to Code 1 (no level beyond local community) one can see once again the monotonic (and precipitous) decline in the sequence HG (88%), SH (62.3%), AH (24.6%), AG (12.8%), consistent with Lenski's overall scheme of the evolution of social inequality. Likewise, combining the percentages for Codes 4 and 5 (state and large state), one sees that states are characteristic of AG societies (50.4%), and to a lesser extent of HE societies (%17.4) and AH (10.8%). With respect to this variable FI societies appear close to SH, with most FI societies having at most one level of hierarchy beyond the local community. I will show below that the number of hierarchical levels is strongly related (in a statistical sense) with the ecological-evolutionary typology.