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CHAP TER 8 Darwinian Archaeologies R. Alexander Bentley, Carl Lipo, Herbert D. G. Maschner, and Ben Marler It may be that the next great developments in The first factor, the environment, centers on the the social sciences will come not from pro- notion that the external world makes things change, fessed social scientists but from people trained but it does not specify how, which is one reason why in other fields. evolution is sometimes confused with environmental —George Lundberg, determinism. The acquired characters factor was ini- Foundations of Sociology tially proposed by Jean-Baptiste Lamarck (1744–1829) to be the engine behind evolution. Lamarckian evolu- A vital notion for all historical sciences, the term tion states that change occurs because entities pass on “evolution” has a myriad of meanings and definitions traits to their offspring that they acquire during their that form the basis of explanations and evoke a range lifetimes. of reactions from advocates and critics. In general, The intrinsic drive related to a goal is one of the however, the term basically refers to change. In this in- most commonly invoked mechanisms for transforma- nocuous sense, most archaeologists would likely con- tional evolution and is related to change in the form sider themselves as evolutionists as the archaeological of development (Carneiro 2003). Here evolution is record is, by its nature, a record of change. In fact, one considered to be change that is directional, a direction of the primary reasons we study the archaeological re- that is often associated with progress (Dunnell 1988). cord is because what exists today is different from that While occasionally invoked in biology (Niteki 1988; of the past and thus archaeology is the study of that Ruse 1997), this finds predominate usage in various change. It is conceivable that few archaeologists would forms of cultural evolution, which holds that hu- argue that the discipline is evolutionary if the word man populations transform themselves, progressing “evolution” is limited to this basic connotation. measurably along a yardstick of progress that is often While there is little controversy about evolution as referred to as complexity (Carneiro 2003). change, explaining change is another matter entirely, Cultural evolution in anthropology dates to the and in this sense the topic of evolution provokes the nineteenth century (Morgan 1877; Spencer 1887; Tylor great emotion among proponents with different no- 1865). During much of the twentieth century, cultural tions of what evolution means. It is useful, then, to de- evolution was largely a European concept (Childe 1944; lineate a series of technical meanings for the concept Figuier 1870; Peake 1928) and was rejected by the ma- of evolution that are helpful to distinguish the various jority of Americanist anthropologists (Holmes 1892). explanatory frameworks that that the word connotes. It was revitalized in the 1960s, however, through the work of Leslie White (1959). As a result of this revital- EVOLUTION AS TRANSFORMATION ization and New Archaeology’s interest in developing The first meaning is one that invokes the idea of trans- explicit frameworks for explaining change, cultural formation. Indeed, its etymology traces back to seven- evolution emerged to form many of the underlying teenth-century roots as a word that means “to unfold, principles of contemporary archaeological explana- open out, expand.” The general concept here is one of tions (Binford 1968; Flannery 1972, 1986; Kirch 1990; transformation that occurs due to innate properties Sahlins and Service 1960; Service 1975; Spencer 1990; and internal activities. In this sense of evolution, two Wright 1986; Yoffee and Cowgill 1992). Cultural evo- factors are commonly identified as the source of these lution approaches assume that change occurs due to transformations: the direct influence of the environ- responses by past populations, whether that is labeled ment, through an inheritance of acquired characters as an adaptation to some stimulus (Binford 1968; and an intrinsic drive toward a definite goal, particu- Boserup 1965; Carneiro 1970; Cohen 1977; Flannery larly toward greater perfection (Mayr 2001:77). 1972; Kirch 1980) or, more recently, agency in which 109 change occurs due to the internal actions of individu- emphases (table 8.1), this leads to a fascinating, almost als within a population in response to perceived states philosophical debate over human intentionality, as in the environment (Dobres and Robb 2005; Pauketat discussed below. 2001; see Gardner, chapter 7). In any case, once these subjects and objects are identified, the tenets above form the basic foundation EVOLUTION AS CHANGE IN VARIABILITY of Darwinian evolution in which change is explained The forms of cultural evolution just described are as the result of a two-step process. First, variability ex- quite distinct from the notion of evolution that under- ists. Second, some portion of that variability persists, lies biology and is the basis of evolutionary approaches some does not. While that may be agreed on, the mil- to archaeology and anthropology. This kind of evolu- lion-dollar question is how and why do some things tion is often recognized as Darwinian evolution due to persist and become more common at the expense its origins. The confusing part is that on the surface, of others? While natural selection—the differential explanations made using cultural and Darwinian evo- persistence of certain traits over others—is usually the lution take a similar form. Darwinian evolutionary null hypothesis in biology, when explaining change in explanations explore “any net directional change or human culture the answer is prone to debate (often cumulative change in the characteristics of organ- heated) in almost every case. Other chapters in this isms and populations over many generations” (Endler handbook describe other mechanisms for evolution- 1986:5). This basic definition for Darwinian evolution ary change, such as drift (see Collard et al., chapter is remarkably similar to the transformation notion of 13) or self-organization (see Bentley and Maschner, evolution: both treat change as directional. chapter 15), and there much debate over when and The Darwinian definition, however, belies two of where natural selection predominates in the process of the basic tenets of biological evolution. The first tenet culture change (see Collard et al., chapter 13; Gabora, of Darwinian evolution is that variation is causal. At chapter 17). However, there can be no doubt at least any point in time, things vary with respect to each that on some time scale (e.g., our evolution from other, and this variability produces change. Variation australopithecines) that natural selection has acted. is causal because the interaction between variability Hence a chapter on evolutionary approaches needs to and the external world produces differential success. define natural selection. The differential persistence of So we explain change due to the details of that vari- entities can be explained as the result of natural selec- ability—how one variant is different than another. tion for evolution of trait T if and only if: The second tenet of Darwinian evolution is that the mechanism of change is external to the things that we 1. Entities vary with respect to T (VARIABILITY) are explaining; change results from the interaction of and entities with the external environment and/or with 2. Different variants of T confer differing probabili- other entities. What is seen as the external selective en- ties of survival and/or replication on the entities. vironment and what is selected is the source of much (FITNESS) of debate, as discussed in this chapter—should we and consider humans as being selected by their environ- 3. Entities transmit their variants of T with better- ment, artifacts as selected by humans, or even humans than-chance fidelity through successive replica- selected by their artifacts or environments modified tions. (INHERITANCE) by humans? Because various approaches differ in their Based on this definition, one can readily appreci- Table 8.1. Dimensions of Variability in Evolutionary Approaches ate how natural selection is different than a transfor- mational type of evolution in which entities change Dimension Variability themselves. Natural selection is not an event per se, Temporal scale Long <-> Short Variation Artifacts <->Behavio but an explanation of a statistical outcome in which <-> Ideas (Memes) variability has been differentially sorted. Natural selec- Transmission Vertical <->Horizontal tion simply explains the distribution of entities in time Subject and object of Humans <-> Artifacts and across space. Second, evolution is what one might selection (Intentionality) <-> Environment Sorting mechanisms Natural selection, consider a mechanistic explanation, in that the enti- transmission, drift, ties provide just the materials (variability) on which phenotypic plasticity change acts. Third, rate of change is not specified. Al- 110 r. alexander bentley et al though evolution is often thought to be gradual, noth- which inheritance occurs. The inheritance of culture ing in the theory requires this. Evolution by natural (cultural transmission) was specifically introduced to selection may result in change or stabilization, and can account for variability and similarity in behavioral be fast or slow. Finally, natural selection does not need traits, as opposed to morphological traits in animals to be a result of nature—the