Elements of an inclusive evolutionary model for archaeology

JOURNAL

OF ANTHROPOLOGICAL

ARCHAEOLOGY

6, 199-219 (1987)

Elements of an Inclusive Evolutionary for Archaeology

Model

ROBERT D. LEONARD’ Zuni Archaeology

Program, Box 339, Zuni, New Mexico 87327 AND

GEORGE T. JONES Department of Anthropology,

Hamilton College, Clinton, New York 13323

Received June 21, 1986 In the following pages it is argued that the transformational, progressive framework of Cultural Evolution often employed in archaeology is limited to the extent that it can but rarely function in an explanatory capacity. It is proposed that the goals of a processualist archaeology can be met more fully by the scientific, inclusive evolutionary paradigm discussed here. Components of this new paradigm, based on a selectionist perspective of change, are introduced. In sum, it is suggested that the construction of an evolutionary theory applicable in archaeology requires that artifacts at any scale be interpreted as part of the human phenotype, and that fitness be assessed through the concept of replicative success. In this fashion, selective mechanisms may be identified and processual explanations of change generated. 6 1987 Academic Press. Inc.

INTRODUCTION

It is our belief that there is a lack of coherent and agreed upon goals in archaeology that is symptomatic of a persistent dilemma: the absence of fundamental definitions and propositions that constitute archaeological theory. One solution to this dilemma lies in the construction of a scientific evolutionary theory that provides a framework for the explanation of archaeological change. Most archaeologists would agree that cultural evolution lies at the heart of archaeology, but we must conclude that it is an extremely vague and inconsistent notion of evolution that is employed. Imagining that archaeology already utilizes a scientific evolutionary theory reflects only that the terminology (or analogs thereof) of the biological model has been adapted for use. This is not isomorphic with the i Present address: Department querque, NM 87131.

of Anthropology,

University

of New Mexico,

Albu-

199 0278-4165187 $3.00 Copyright 0 1987 by Academic Press. Inc. All rigbt.3 of reproduction in any form reserved.

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development and use of theory. Theory is constructed and necessarily involves self-conscious evaluation of concepts and the ways in which meaning is supplied to the archaeological record (Binford 1977). However widely appreciated this may be, there seems to be a general ambivalence toward theory construction (Dunnell 1984), and there is certainly insufficient self-conscious evaluation of the model of cultural evolution currently in vogue. Can a scientific evolutionary theory be constructed that will provide a viable means of explanation in archaeology? Is scientific evolution necessarily capable of giving different and better understandings of the past? We think so, and importantly, we believe it is a most appropriate course to meet the espoused processual interests of archaeology. While it is simple for us to make this assertion, it is another thing to show how scientific evolutionary theory will perform in the service of our interests, particularly when it is unclear what that theory will look like. Two models of evolution have been given serious consideration by archaeologists: a transformational, progressive framework of Cultural Evolution and a selectionist framework of biological evolution. (Throughout this article, the phrases “Culture Evolution” and “Cultural Evolution” refer to the first model only; capitalization is used to emphasize that we are referring to the set of concepts encompassed by the first model, as distinguished from the common use of the terms as broad synonyms for change.) While we are critical of Cultural Evolution, our discussion will be brief for two reasons: first, the problems with the model relate to its basic construction, not to the details of its application; second, extensive treatments which address the major strengths and weaknesses of the model and how it has been applied in archaeology have recently been offered (e.g., Dunnell 1980; Kirch 1980; Rindos 1985). Our criticisms of Cultural Evolution are few, but we feel that they are of consequence. Attributed to Spencer, and built upon primarily by Sahlins, Service, and White (e.g., Sahlins 1960; Sahlins and Service 1960; Service 1962, 1971; White 1949), among others, the model of Cultural Evolution is demonstrably inappropriate as a scientific archaeological paradigm for several reasons. Among these reasons are, first, it is essentialist and, in concert, is typological at an inappropriate scale. Invariably, applications of the model are conceived at a scale much too inclusive and indiscriminating for culture change to be monitored, and, in fact, the model serves to obscure change at the scale at which it primarily occurs (i.e., consider the material variation and culture change that goes unnoted with the punctuated stages of evolution that the model demands). Second, as a consequence of having a minimal and mostly implicit role for natural selection, Culture Evolution fails to distinguish between the processes that generate variation and those which select for particular

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variates. Third, it implies progress where only change exists (Dunnell 1980; Rindos 1985). Finally, it is structured such that virtually only prime mover explanations may be generated (to initiate culture change through the stages of the model, i.e., bands, tribes, etc., only prime movers can exert sufficient selective force). Given these problems, it is our opinion that for a processual archaeology with emphasis on empirical variation and a nonprogressionist perspective, a model based upon the general selectionist tenets of scientific evolution is more appropriate. In reaching this conclusion, others (e.g., Cavalli-Sforza and Feldman 1981; Durham 1982) have set about to design a complementary theory of culture change modeled after the biological constructs of neo-Darwinian theory. We suggest a different strategy to theory construction, namely, to broaden the applicability of serviceable concepts in what we envision as an inclusive evolutionary theory. CULTURAL

EVOLUTION

Before the inclusive evolutionary model is considered, it is necessary to discuss in more detail a number of reasons why we feel that the transformational, progressive framework of Cultural Evolution (e.g., Sahlins and Service 1960; Service 1962, 1971; White 1949) is not complementary with, and in fact hinders, the development of a scientific evolutionary paradigm. Indeed, a major portion of our thesis rests upon our conclusion that the conceptual makeup of the Cultural Evolution paradigm is antithetical to Darwinian evolution (Dunnell 1980) and must therefore be incompatible with the inclusive model we propose. Several recent critiques of Cultural Evolution (e.g., Dunnell 1980; Harris 1968; Wenke 1981; Yoffee 1979) have identified a range of weaknesses in that paradigm. Among those, Dunnell (1980) notes at least four: (1) the evolution of culture is thought to be directional and progressive; (2) empirical generalizations about the course of cultural change are confused with general mechanisms such as natural selection that account for culture variation; (3) a phenomenological focus that views culture and not empirical variation as the subject matter of interest and consequently regards change as transformations of culture rather than changes in the frequencies of ideational, behavioral, or material variables; and (4) the use of cultural taxonomies that characterize evolutionary stages and embody a notion of progress. Such criticisms have not gone unheeded. As Flannery (1983) notes, over the past decade interest in general evolution has been superseded by the less radical elements of specific evolution. Moreover, there have been changes in attitudes regarding basic elements of the Cultural Evolution paradigm. For instance, we notice subtle changes in the meaning given to

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evolution, presumably to bring Cultural Evolution more closely in line with the Darwinian model. Greater care is exercised in the use of the term “progress.” Recently, for instance, Flannery (1983: 1) has defined evolution as taking place where “successive generations of organisms diverge progressively from their ancestors.” While the term progress is retained, it surely is not intended to convey the same meaning as in Sahlins’ (1960:13) statement that “evolution generates progress: higher forms arise from, and surpass, lower.” Similar changes can be seen in that one can definitely sense a rising insecurity in archaeological writings, with regard to the validity of the stages required of the Culture Evolution model, from the increasing use of quotation marks surrounding “tribes,” “chiefdoms,” etc. (e.g., Braun and Plog 1982; Creamer and Haas 1985). Braun and Plog, for example, title their paper “Evolution of ‘Tribal’ Social Networks: Theory and Prehistoric North American Evidence.” Apparently, discomfort with the Cultural Evolution typology dictates that one no longer discuss tribes and chiefdoms; one discusses “tribes” and “chiefdoms.” This topic is not raised here to be critical of the work of these authors but to raise the issue that the utility of these principal concepts of Culture Evolution is being, at least implicitly, brought into question. Concomitantly, it is important to state that neither the increased use of quotation marks nor the continued use of the Culture Evolution model implies that the typological scheme of the Culture Evolution paradigm is being used simply as a heuristic device. This is simply not the case. Creamer and Haas, for example, summarize their work in this quotation from the abstract of their paper (1985:738): “The salient characteristics of both tribes and chiefdoms are discussed, and criteria for identifying tribes and chiefdoms in the archaeological record are outlined. Data from the Central Provinces of Panama and the Gulf of Nicoya are then examined in light of these criteria. We argue that while a chiefdom form of organization prevailed in Panama, the Gulf of Nicoya was occupied by tribal groups immediately prior to contact with the Spanish.”

Clearly, if this quotation from the abstract can be used to judge the content of their paper, tribes and chiefdoms are fundamental analytic units employed by Creamer and Haas, not mere heuristic devices. Our target here is clearly not a heuristic device, nor is it a “straw man” of our construction. Despite apparent attempts at revision (e.g., Flannery 1983) and at least some implicit discomfort with the Culture Evolution typology (e.g., Braun and Plog 1982; Creamer and Haas 1985), much of what comprises contemporary applications of the Cultural Evolutionary paradigm, and that which makes it incompatible with a selectionist model, is illustrated

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in the following brief excerpt in which Marcus (1983:9) discusses the divergent evolution of the Zapotec and Mixtec civilizations: “As the Cloud People diverged from a common ancestor, they, like the Maya . . underwent changes of three kinds. They adapted to diverse environments; they underwent unselected “drift”; and they were influenced by neighboring foreign cultures. At the same time, they retained a whole series of characteristics that set them apart from other Mesoamerican peoples and that continued to provide evidence for their common ancestry despite modification and readaptation. One challenge of Oaxacan archaeology is to understand how all those diverse processes produced the cultures we know as Zapotec and Mixtec.”

The transformational nature of this view of evolution is quite apparent. While recognizing that cultures have characteristics upon which they are defined, the concept “culture” constitutes the scale of analysis. The Cloud People, as a cultural unit, adapted to diverse environments, underwent unselected drift, and were influenced by neighboring foreign cultures (foreign cultures being another comparable unit). Evolutionary processes, and thus selection, are seen as operative at the scale of culture. For evolutionary change to take place at this scale, selective mechanisms must also be of similar scope. Given this perspective, it is not surprising that selective forces, when discussed in Mesoamerican prehistory, take the form of prime movers: monumental forces such as plagues (Spinden 1928), major climatic changes (Shimkin 1973), foreign military conquest (Cowgill 1964; Sabloff and Willey 1967), ecological collapse (Culbert 1974), and class conflict, among others. We do not deny that selection may operate at the scale of culture; one need only to consider the plight of the Tasmanians in the last century to accept this role for selection as a mechanism. We simply stress in the following pages that it is variation across characteristics within populations that constitutes the primary focus of selection and thus evolutionary change. As to the ascendancy of specific evolution in the cultural evolution paradigm that Flannery notes, it is only superficially that specific evolution appears to be more easily reconciled with Darwinian evolution, as it is not easily decoupled from the progressive framework evident in the writings of unilineal evolutionists of the last century. Continuation of this intellectual tradition is no more clearly expressed than in the continued, often casual, references to stage classifications of sociopolitical integration and social organization which embrace progressive change. The stage typology of Cultural Evolution has not, and perhaps cannot, escape the Spencerian notion of progress. CLASSIFICATION

It is difficult

IN EVOLUTIONARY

to deny the basic organizational

MODELS

utility of such typologies

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as those of Service (1962) or Fried (1967), but we note that their basic structure, and importantly, their uncritical use in archaeology has perpetuated a transformational view of culture change. This is perhaps unavoidable, given that the Culture Evolution model is an essentialist, as opposed to a materialist, framework. Dunnell (1985: 153) outlines the differences between the essentialist and materialist manners of perception: “Many authors have distinguished between essentialism, or typological thinking, and materialism, or population thinking (e.g., Dunnell 1980, 1982; Hull 1965; Lewontin 1974; Mayr 1959, 1982; Sober 1980). In the essentialist view, the phenomenological world is taken to be constituted by a finite set of discrete entities, between which only variation is of explanatory significance. Internal variation is regarded as “noise” arising from imperfect expression in a contingency-bound world. This view implies a methodology directed toward distinguishing difference, the variation between kinds, from noise. The materialist holds that “kinds” are illusory, transitory configurations; it is the observed variation that is of explanatory significance. Noise is epistemological, not ontological, and limited to measurement error. There is no right or wrong position in absolute terms; however, there are practical differences of methodological import for unit construction. As Lewontin (1974) has pointed out, the materialist ontological position is prerequisite to studying change as distinguished from difference. Obstensibly, the study of change is a major focus and unique contribution of archaeology. Within the essentialist framework, explanation is limited to “how does it work” kinds of questions. What are the interactions between kinds? Within the materialist framework, explanations can address the “why does it exist” kinds of questions.”

The essentialism inherent in Cultural Evolution can be seen in the procedures Creamer and Haas (1985) use to decide whether the prehistoric peoples living near the Gulf of Nicoya, Costa Rica, and Central Panama were participants in tribe or chiefdom-level societies. Creamer and Haas are very explicit and straightforward in the construction of their definitions and in their application of the model. They outline 11 classificatory distinctions that are used to differentiate between tribes and chiefdoms: differences in settlement patterns, architecture, centralization of labor, surplus production, storage, specialization, rank, status goods, regional and interregional trade, boundaries, and stress (1985:742). Tribes are represented by certain characteristics, chiefdoms by other characteristics. For example, with respect to settlement patterns, tribes are expected to have “sites composed of similar constituent units dispersed over a definable region.” Chiefdoms alternatively should have “At least two levels of site hierarchy; structurally distinct central place.” The authors found that at the Gulf of Nicoya “sites vary in size but not in structural components; no functional differentiation within sites.” In central Panama they discovered “At least two distinct types of habitation site; one is regional central place.” The differences outlined here allow the authors to eventually conclude, in conjunction with considerable additional evidence, that the prehistoric peoples of the Gulf of Nicoya were organized into tribes,

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while people in central Panama had a chiefdom level of organization. To Creamer and Haas, despite a brief caveat presented early in the paper regarding the validity of stage typologies, tribes and chiefdoms exist a priori, and the organization of the prehistoric peoples they were studying could be categorized into either of the two types. The possibility of additional or different means of organization or even changes through time in the organization of either group is not seriously considered. This is a perfectly reasonable application within an essentialist construction. There is a finite set of discrete entities, in this case tribes and chiefdoms, and internal variation is regarded as imperfect expression. As is common in essentialist applications, one of the central purposes of Creamer and Haas’ analysis was to outline the differences between the groups and to make the organizational assignments of tribe or chiefdom. While Creamer and Haas were successful in their assignments, it is clear that the essentialist framework disallowed that there might be more organizational possibilities than tribes and chiefdoms. Tribes and chiefdoms, as typological constructs, possess a long history of use in anthropology and, as such, have “essences” that are almost intuitively obvious. A materialist framework, alternatively, in focusing on variation, would operate under no a priori consideration that tribes or chiefdoms were the only possible means of organization for the two groups Creamer and Haas studied, nor are bands, tribes, chiefdoms, and states the only possible means of organization for all societies. As one of those responsible for the refinement of the Culture Evolution paradigm, Service (1962) nevertheless by no means argued that the typology presented was the only possible one or that it was necessarily useful or valid: “It would seem that qualitatively distinct means of integration are few in human society. They appear to be five in number . . (1) familistic bonds of kinship and marriage which by their nature can integrate only the relatively small and simple societies that we call bands; (2) pan-tribal sodalities which can integrate several bandlike societies into one; (3) specialization, redistribution, and the related centralization of authority which can integrate still more complex societies; (4) the state, further integrated by a bureaucracy employing legal force; (5) an industrial society integrated not only by a state apparatus but also by a complex network of specialized, interdependent occupations. Only the first three of these have been used in this book, and not enough data were brought together to make a good test of the usefulness of the assumptions that underlie them. Further tests should be made with a large and broad sample of primitive societies which, when separated into the three categories of complexity, would reveal the extent to which the assumptions reflect reality. First of all, if the forms of integration described in the classification are in fact qualitatively distinct rather than continuously linked, and if they are in fact necessary to an appropriate size and complexity of the society, then the three classes of societies should actually appear as distinct levels. That is, there should be ‘day-

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light’ between each class in the sense that many societies should be clustered at each level and fewer ranged in between them. At the same time the assumptions about internal functional necessity are testable. If there are actually three clusters, it would be a simple matter to discover what aspects or traits of culture go together. If the societies form a continuous gradation instead of clusters, then rank ordering, scaling, or some such more sophisticated method could be used. These tests have not been made. The present book is only a crude beginning, little more than an argument in favor of hypothesis, for an enormous amount of work lies ahead . . .” (1962:181-182)

Despite Service’s reservations regarding the validity of the proposed typology of Cultural Evolution, neither rigorous evaluation of the typology nor the consideration of alternative typologies has occurred. This is not so surprising given the obvious organizational utility of the model for anthropologists and the fact that the model had been built on several generations of anthropological thought regarding social organization. Somewhat unexpectedly, however, even nonanthropologists find the model so obviously useful as to embrace it with little or no evaluation [e.g., the biologist Alexander (1979a)] despite the inherent essentialism incompatible with evolutionary studies of change. Creamer and Haas (1985) felt the validity of the model to be so sufficient that the assignment of tribe and chiefdom labels to the societies under study could be made quite reliably and that the assignment itself supplied meaning to their analyses. Yet, what happens when far more than two societies are considered and when different and/or additional means of societal organization are offered within a materialist framework? It is our observation that there is far more variation than accounted for by these stage taxonomies. What is the empirical basis for this assertion? In the spirit of Service’s suggestion regarding the continued evaluation of the model, we have drawn information from the Ethnographic Atlas (Murdock 1967) on a small number of classificatory attributes that at one time or another have been used by archaeologists to assign prehistoric societies to Culture Evolutionary stages. As we have noted, many attributes have been considered; we have chosen three for illustration: community organization, settlement pattern, and class stratification.‘,* Here, we feel that there is little need to justify the choice of attributes selected, other than to maintain that these have been used before by others. Our point could be made as well with more or different attributes. The accuracy of the Ethnographic Atlas is also largely irrelevant, as it is delimiting a pattern, not the examination of class assignments or the creation of an all-purpose classification, that is our goal. As a means of classifying societies, we have chosen to use paradigmatic classification (Dunnell 1971) because of the considerable amount of variation that this type of classification allows to * See Notes section at end of paper for all footnotes.

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be expressed. Other means of classification may have served equally well, but few other classificatory or typological structures are so competent at describing variation. Put most simply, paradigmatic classifications employ dimensions (attributes or variables) and modes (alternative attribute or variable states), creating classes by intersection. For example, the dimension color encompasses the alternative modes red, blue, yellow, etc. When a classification is composed of several dimensions and associated modes, many classes are created. For the purposes of illustration, consider that a classification based on the color and size of an object might include the respective modes of color, red, blue, yellow, and size, large and small. This classification comprises six classes (3 x 2, the number of modes in each dimension multiplied by each other; for a more detailed discussion of paradigmatic classifications see Dunnell 1971). Employing the modes presented in the Ethnographic Atlas for each of these dimensions (see Table 1 for a list of dimensions and associated modes), we have created a three-dimensional paradigmatic classification containing 240 classes (6 x 8 x 5). Presumably, among this number are three or four classes that approximate Cultural Evolutionary stages in use. When the ethnographic record is examined for the distribution of societies with respect to this classification we find 118 classes represented by members. Their frequency is shown in Fig. 1, in descending order, from an abundance of 47 members in the largest class to a series of classes with very few members. (Paradigmatic classifications often create classes with few or no members; e.g., if one were creating a classification that had, for whatever purposes, two dimensions, birds and color, you would likely never find members to fill the classes “red, avocet” or “green, pelican.” You would, however, find “red, cardinals” and “green, macaws”). What is most striking about these data is that far more than four classes are represented. The variation documented in this classification is great, and no justification for bands, tribes, chiefdoms, or states in this synchronic view of the empirical record is apparent. Human adaptation is a much more complex phenomenon than such essentialist concepts recognize, and their use surely obscures variation in such a manner that scientific evolutionary models of change are extremely difficult to formulate. While one might be tempted to suggest that our classification is much too divisive and results in too many classes, it must be remembered that only three dimensions (variables) with their attendant modes (alternate variable states) were used in class construction. Moreover, how much different would the outcome have been if additional attributes such as architecture and trade had also been included as dimensions in the classification, except to have identified an even greater number of distinct classes?

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TABLE 1 DIMENSIONS AND MODES USED IN THE PARADIGMATIC CLASSIFICATION OF SOCIETIES~ Dimension 1 Community organization. The prevalence of local endogamy, agamy, and exogamy, together with the presence or absence of localized kin groups, is indicated by the following symbols (used as modes in this classification)b A Agamous communities C Clan communities D Demes E Exogamous communities S Segmented communities T Segmented communities with local exogamy Dimension 2 Settlement pattern. The prevailing type of settlement pattern is indicated by the following symbols (used as modes) B Fully migratory or nomadic bands H Separated hamlets N Neighborhoods of dispersed family homesteads Seminomadic communities S T Semisedentary communities V Compact and relatively permanent settlements W Compact but impermanent settlements X Complex settlements Dimension 3 Class stratification. The degree and type of class stratification, excluding purely political and religious statuses, are indicated by the following symbols (used as modes) C Complex stratification D Dual stratification E Elite stratification 0 Absence of significant class distinctions W Wealth distinctions n Excerpted from Murdock (1967). We provide here an abbreviated version of Murdock’s comments. For more detailed descriptions, see Murdock (1967). b The creation of classes is perhaps best illustrated by example. Consider, for instance, that class CHO includes all societies that are clan-communities, residing in separated hamlets, with no class distinctions being obvious. Of course, many possible classes have no members. See Dunnell (1971) for further discussion of paradigmatic classifications.

Yet, can the classes we have formulated be subsumed further into the typological stages of Culture Evolution? While our example was constructed using those attributes (community organization, settlement pattern, and class stratification) considered by archaeologists to be useful criteria in making band, tribal, chiefdom, and state-level designations of societies, we found that our classes at times reflected the designations assigned by Murdock (1967) and at other times Murdock’s designations were not mirrored. Consider, for example, the societies identified as members of three particular classes, DVC, DSO, and SVC. Class DVC

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(those societies having demes, compact and relatively permanent settlements, and complex stratification) has Egyptians, Ukranians, Hungarians, Turks, Lebanese, Min Chinese, Burmese, and the Inca as members. All societies of this class are considered to be large states. Class DSO (those societies with demes, seminomadic communities, and absence of class distinctions) are, as is to be expected, considered by Murdock (1967) to be stateless societies. Class members include the Copper Eskimo, Beaver, Hukundika, Sinkaietk, Panare, Shiriana, and Coroa. Yet, Cultural Evolutionary categories fit, by no means, the majority of societies. Consider, for example, that Class SVC (those societies having segmented communities, compact and relatively permanent settlements, and complex stratification) has the Oyo Yoruba, Zazzagawa, Shantung, Khasi, Annamese, and Aztec societies among its members. While the Khasi and Aztec are considered by Murdock to be petty and larger paramount chiefdoms, respectively, the Annamese, Shantung, Zazzagawa, and Oyo Yoruba are considered to be state-level societies. Clearly, the appearance of a directional, progressive quality attributed to culture change in archaeology is due to the choice of analytic scale above the one illustrated here, that of the stage typology of Culture Evolution. Were societal variation and change through time examined at finer scales as we have shown, and variables treated equivalently, we are less certain that a directional character in the empirical record would be so apparent. What also becomes apparent with this consideration is that classification within evolutionary studies needs to be problem specific; no stage taxonomy, and certainly not the classification we have constructed here for illustrative reasons, can serve all purposes (we suggest that our classification serves only the purposes of this illustration). For studies of evolutionary change, one must specify the variables under scrutiny and construct dimensions and modes that are pertinent to the documentation of variation and the identification of selective forces. In sum then, and contrary to the tenets of the Culture Evolution paradigm, evolution is not best perceived as the transformation of culture itself or even of the finer scale traits under consideraton. Evolution is change through time in the frequencies of empirical variables (material variables in archeology) scaled at the appropriate levels of inclusiveness (i.e., selected at a scale that allows one to monitor changes in the variables of interest; in most applications neither “cultures” nor “societies” but specific components of those or similar constructs are the likely units of investigation). Our example (Fig. 1 and associated text) shows that the typological units of the Cultural Evolution paradigm, particularly when adapted to archaeological use, obscure considerable variation because they are, for most purposes, improperly scaled for the problem at hand. Moreover, their use gives the impression that change is directional and

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encompasses far less variation than is the case. The inattention to variation is one of the fundamental shortcomings of the Cultural Evolution paradigm, for variation is the focus of selection, and without variation as a basic concept of an evolutionary theory, the role of selection is perceived as being minor. This is unfortunate, as it is primarily through the identification of selective forces that processual explanations are built. For their part, multicausal models of culture change have provided more realistic perspectives on process, but they too are essentialist and certainly hobbled by a transformational view of change. It is clear that the challenge of processual archaeology lies in the recognition of empirical variation and the operation of Darwinian selection. THE INCLUSIVE

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It is important at this point to stress that a rejection of the Spencerian model of Cultural Evolution in favor of one incorporating Darwinian selection demands neither the subsumption of archaeology under the rubric of modern evolutionary biology nor an acceptance of the tenets of sociobiology. We also do not suggest that a theoretical account of scientific evolution applicable to cultural phenomena must be built upon a completely different, yet redundant, conceptual footing. Although it was developed in modern biology and refined by the evolutionary synthesis, scientific evolutionary theory need not be restricted to a particular class of phenomena, i.e., genes and/or species. Its simplicity and explanatory power give scientific evolutionary theory wider applicability in studies of change. A number of authors have suggested that scientific evolution may be expanded to provide an explanatory framework for cultural phenomena (e.g., Boyd and Richerson 1982; Cavalli-Sforza and Feldman 1981; Dunnell 1980; Durham 1982; Rindos 1984, 1985). Such expansions are by no means reductionist but are a consequence of the historical development of a theory of general utility in the context of one specific application thereof-modern biology. In subsuming both the archaeological and biological paradigms under a more inclusive evolutionary theory, we recognize that many of the same processes affect phenomenological categories of both sorts. Consequently, we view such analogous concepts as cultural selection (e.g., Cavalli-Sforza and Feldman 1981) as being largely redundant and a source of confusion. Within a more inclusive framework, studies of both biological and cultural phenomena retain common concepts but are free to model and describe mechanisms that pertain primarily to those phenomena, including both genetic and cultural modes of information transmission. While an inclusive evolutionary theory is expansive in that it encompasses a wider set of historical events, the theoretical structure of the

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evolutionary framework itself need not change. In the broadest sense, evolution constitutes any change in the form of a frequency distribution that persists across generations (Futuyma 1979). In this context, cultural characteristics are homologous with and equivalent to physical traits of all organisms and have such observable frequency distributions. The requirements of scientific evolutionary paradigm are actually quite simple: that the phenomena under study (1) exhibit empirical variability, (2) a mechanism for the transmission of some of that variability, and (3) the operation of selective factors that can account for the differential persistence of variability (Dunnell 1980). Working from their specific perspectives, biologists have correctly identified the transmission mechanism of biological variability as being genetic and noted that the differential persistence of variability in natural populations is a consequence of the differential reproductive success of individuals in those populations. Such specifications, although necessary and valuable to evolutionary genetics, are the very reason that a biological theory of evolution, rather that a more inclusive construct, is an inappropriate model for cultural phenomena. Not only do the modes of transmission and the traits transmitted differ between biological and cultural systems, but changes in the latter may occur more rapidly than generation time (Durham 1982; Rindos 1985) and without any necessary expression in, or ultimate affect on, the gene pool. The cultural transmission of traits is a complex of independent mechanisms for information transfer, which are by no means fully understood (see various models proposed by Boyd and Richerson 1981, 1985; Cavalli-Sforza and Feldman 1981; Pullium and Dunford 1980). It is clear, however, that the distinctiveness of cultural transmission is not that it is Lamarkian, as some have incorrectly suggested (e.g., Alexander 1979b; Gould 1980). Whether a character is derived or not, its fitness and expression through time is nevertheless governed by selection, It is important to recognize when dealing with the components of cultural systems that the differential persistence of variation is not solely accomplished through differential reproductive success but also through differential replicative success of traits themselves. This matter will receive further discussion below. The recognition of the genetic transmission mechanism in biology has hindered the application of a scientific evolutionary theory to cultural phenomena. Many archaeologists have correctly rejected the biological model for the explanation of variation in cultural phenomena as too narrow but have not considered a more inclusive model of change under which both could be subsumed. Instead, they have decided to construct complementary models, which acknowledges the explanatory power of the biological model in a search for analogies applicable to cultural phe-

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nomena. Had a more inclusive evolutionary model been envisioned, more appropriate homologies of structure might have been recognized. Beyond structural homologies, specific concepts drawn from the biological paradigm are seen as more broadly applicable in an inclusive evolutionary model. Such a concept is the phenotype. Mayr (1970:442) defines phenotype as “the totality of characteristics of an individual (its appearance) as a result of the interaction between genotype and environment.” This definition subsumes both physical and behavioral components of the individual and, in keeping with the spirit of the concept, necessarily includes cultural acquisitions as part of the human phenotype. It follows that material culture-artifacts of any scale-is an expression of human behavioral variability and thus should be regarded as one class of cultural traits and hence a component of the human phenotype. The evolutionary framework proposed here argues for the inclusion of cultural phenomenaspecifically material remains-as an expression of phenotypic variability. Change must not be viewed as transformations of the traits themselves but in the frequencies of the traits through time. With that in mind, we suggest that cultural change may be monitored as deviations through time in the frequency distributions of attributes or classes of material phenomena. Once frequency distributions are constructed and scaled chronologically, the mechanism(s) of selection can be isolated and archaeological explanations built. Through these means, the application of a selectionist theory of evolution is made operational. The role of quantification, while simple, provides a consequential tie from a scientific evolutionary theory to the phenomena under study. The means of quantification, as well as the selection of the sample quantified, can be evaluated, improved upon, validated, or rejected. Most important, the respective parsimony and sufficiency of hypotheses proposed as potential explanations may be verifiably evaluated in terms of the distributions for which explanations are sought. Without actual distributions of material phenomena through which the fit of proposed explanations may be compared and evaluated, we are reduced to offering explanations for unverified empirical generalizations at best and for conjecture at worst. In assessing the role of selection on the persistence and character of variation in biological populations, a criterion of reproductive success has been stipulated. Yet how the differential representation of cultural traits relates to individual fitness is not spelled out clearly in theory constructed to date. We believe there is a broader issue to which Rindos (1985) alludes when he notes that the transmission and differential persistence of cultural traits over time is apparently less related to the reproductive success of the holders of those traits than to the fitness of the traits themselves. While the differential reproductive success of indi-

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viduals may influence the expression of cultural variation, it does not determine it. How then is the fitness of cultural traits evaluated? REPLICATIVE

SUCCESS

All traits, whether material or behavioral, have distributions in time and space, and all traits have what may be termed replicative success, or differential persistence through time. Human cultural traits have differential replicative success in the same fashion that particular traits of animals (e.g., coat colorings, tail lengths, etc.) have differential replicative success. We maintain a distinction between individuals who have differential reproductive success and the traits of those individuals which have only replicative success. The replicative success of a particular trait may or may not affect the reproductive success of the bearer. Those that do may be considered functional and those traits with no selective import termed stylistic or neutral (sensu Dunnell 1978). We recognize here the arguments that exist regarding the problems identifying neutral traits (cf., Kimura 1983; King and Jukes 1969), and the fact that because we cannot identify the function of a trait does not mean that it has none. We also recognize that most contemporary usage of the term “style” in archeology does not follow the usage prescribed by Dunnell (1978). We do, however, maintain that the use of the concept “style” as structured by Dunnell (1978) has the potential to be employed in the manner outlined above. The important point here is that in our selectionist model, each trait has a Darwinian or replicative fitness, which may or may not affect the Darwinian fitness of its bearer. Replicative success is a pragmatic construct. It implies neither a mode of trait transmission, as reproductive success does, nor that some degree of selective advantage or disadvantage is conferred as a result of the transmission of a trait. Success is gauged as changes in the representation of traits through time. Only through linkage to a class of traits, i.e., whether the trait is with or without selective value, and the specification of the selective environment does the distribution of a trait assume an expectable temporal pattern. For example, the replicative success of a stylistic trait can be evaluated against a monotonic model for the behavior of style in time. We should not expect in this instance that the trait’s temporal behavior will be governed by environmental agencies but instead by stochastic processes (Dunnell 1978). In proposing the concept of replicative success, we again have stressed the equivalence of different categories of traits, e.g., physiological, behavioral, and artifactual, that are treated unequally or not at all in biological or Cultural Evolutionary theory. Although these classes may be referents of distinctive kinds of information, they nonetheless represent

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equivalent counting units. In the inclusive model these trait classes are homologous. This negates a criticism often leveled at expressly evolutionary considerations of material remains: artifacts do not propagate and thus can have no delimitable reproductive success. On this issue, Brew (1946), among others, has criticized the zeal with which archaeologists have extended the genealogical or phylogenetic metaphor to ceramic change in the American Southwest. His objection to taxonomic systems for ceramics modeled upon Linnean biological classifications is that pottery classes are not organisms and do not reproduce. It is difficult not to appreciate his argument. Brew (194659) writes: “. . . we still are faced with the fact that, with the exception of skeletal material, the objects and concepts of archeology are not living organisms or parts of living organisms. Consequently, their development is not properly represented by a classificatory technique based upon the genetic relationships of living organisms.” But just the same, we must ask if the skeletal material Brew refers to, or even the parts of living organisms, reproduces in a manner identical to that of an individual. It does not. Like other kinds of traits, artifacts need not, in fact cannot, assume the logical status of individuals with reproductive capabilities. Instead, as a quality of the phenotype, artifacts are the equivalents of physical and behavioral traits. None is capable of reproduction, but each incorporates useful phenomenological classes which are the measurable units of change. The selective factors governing replicative success among these broad classes undoubtedly differ with occasion and to the degree that each class is affected, just as the mechanisms of transmission are not isomorphic among different classes. Evolutionary change may occur at many scales, wherever heritable variability and the differential persistence of variability may be discerned. While artifactual traits are commonly identified and examined at the scale of discrete object, certainly more and less inclusive scales are also subject to selection and can be monitored as frequency distributions. Consider, for example, the class abundances of societies depicted in Fig. 1. If it were possible to construct similar histograms for, say, 50-year intervals over the last 10,000 years, an amazing perspective on the evolution of human society would have been generated through examining changes in class abundances and the subsequent consideration of the role that selection played in determining those abundances.2 CONCLUSIONS

Naturally, in such a brief exposition we do not presume to consider all entailments of an inclusive evolutionary theory. Still, it is possible to show that such a theory can explain change in contexts outside the scope

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of biology or evolutionary genetics. While we have made a strong argument to construct such a theory, we do not think that this effort is best served by further attempts toward developing a theory of cultural selection parallel to, yet relatively isolated from, the biological paradigm. Doing so is inefficient, but equally important, it preserves an unfounded distinction captured in the human/nature dichotomy. In setting humans apart from other kinds of organisms in evolutionary studies, we face considerable difficulties in, among other things, coming to grips with the historical transition from predominantly genetic to predominantly cultural modes of information transmission. We have suggested a different strategy for theory construction, but we acknowledge that our suggestions may differ from other efforts primarily at the scale at which they are conceived. While at some level there may be a significant divergence between biological and cultural change, as perhaps in the shift from simple to complex societies (Dunnell 1980; Wenke 1981), we do not recognize fundamental differences at the more general levels of theory discussed here. Where divergence occurs, the modes ‘of information transmission and the units of selection are trivially different. Under the theoretical framework discussed here, physiological, behavioral, and artifactual traits are equivalent phenomenological classes, each governed by the replication criterion. Like these other classes, artifacts at any scale can be regarded as components of the human phenotype and thus legitimate referents of change under an inclusive evolutionary paradigm. In sum, we expect that an inclusive evolutionary paradigm must minimally incorporate cultural acquisitions as part of the human phenotype, a broadened phenomenological realm within which evolutionary change is monitored, and the recognition that selective mechanisms may operate at many scales of inclusiveness. ACKNOWLEDGMENTS We thank Charlotte Beck, Charlotte L. Benson, David Braun, Catherine Cameron, Robert C. Dunnell, Steve Durand, Pamela Ford, Patricia A. Gilman, Donald K. Grayson, Barbara Hildebrant, Shirley Powell, David Rhode, David Rindos, Patricia A. Ruppe, E E. Smiley, Patrice Teltser, Regan Vercruysse, and Robert Whallon for their helpful comments on earlier versions of this paper. We also thank Ronald Stauber for drafting Fig. 1.

NOTES t Presenting all of the class assignments for the 863 societies used in this example goes beyond the purposes of this article. For a complete listing of class assignments, please write either author. * While class assignments were not presented for reasons given in the above note, classes

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with the greatest replicative success (those to the left of Fig. 1) are for the most part, represented by members that would often be called hunter-gatherers. It is interesting to note that while classes representing these societies have had great replicative success (but which now is likely declining), class members have not had great reproductive success as of late.

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