P RO M E T H E US P R E S S / P AL A EO NT O L OG I C AL N ET W O R K F O U ND AT I O N Journal of Taphonomy (TERUEL) 2005 Available online at www.journaltaphonomy.com Pobiner & Braun VOLUME 3 (ISSUE 2) Applying Actualism: Considerations for Future Research Briana L. Pobiner* & David R. Braun Anthropology Department, Rutgers University, 131 George Street, New Brunswick, NJ 08901, USA Journal of Taphonomy 3 (2) (2005), 57-65. Manuscript received 29 April 2005, revised manuscript accepted 31 May 2005. This paper serves as an introduction and discussion of a collection of five papers originally presented in a symposium held at the 69th meeting of the Society for American Archaeology in 2004 entitled “Applied actualism: Experimental studies of hominid activity traces”. These papers primarily present actualistic studies aimed at addressing questions of hominin carcass processing activities, generally using cutmark data. They serve as a reminder of the utility and importance of actualistic studies to test hypotheses of hominin behavior using zooarchaeological and taphonomic data. We review the manner in which actualism is used in these various studies of human butchery practices to construct models to generate test implications for the archaeological record. Finally, some considerations for future actualistic work are discussed. Keywords: , geologists in the nineteenth and twentieth centuries, was followed by early taphonomists who focused on observations of modern processes resulting in bones be ar in g p ar t ic u la r mo d if ic a ti on s (Behrensmeyer & Kidwell, 1985; Lyman 1994). A review of the theoretical underpinnings of actualism, uniformitarianism, and analogy, and how they are incorporated into taphonomic and archaeological research, can be found in Gifford-Gonzalez (1989) and Lyman (1994:47-69). Implementing actualism in Actualism: A Basic Understanding “By facing the analogic nature of much archaeological reasoning, we have been able to move into more self-critical, rigorous, and productive research practice” (GiffordGonzalez, 1989:49). Actualism can be defined as “the methodology of inferring the nature of past events by analogy with processes observable and in action in the present” (Rudwick, 1971:110). This uniformitarianist approach, used by Article JTa030. All rights reserved. * E-mail:bpobiner@rci.rutgers.edu 57 Applying Actualism signature criteria discriminating one agent or process from all others. This “if and only if” framework is aimed at avoiding equifinality, which can be defined as the property of allowing or having the same effect or result from different events (Munro and Bar-Oz, 2004). taphonomic and archaeological research can be described as doing the following: Researchers observe modern processes in action. They establish causal relations between these particular processes and particular static effects or traces. They then match the modern record to the past, inferring similar processes for similar traces on the basis of causal relations and relational analogies (Lyman, 1994). Relational analogies are those in which as soci ated at trib utes ar e interdependent or causally related (Wylie 1982). Gifford-Gonzalez (1989:46) states that “the goal of actualistic research should be to distinguish causal/functional relations, even in circumstances of substantial ecological and/or cultural continuities between the observable present and the investigated past.” It has been further argued that embracing clusters of relational analogies instead of a single line of evidence allows for greater confidence in the conclusions drawn from actualistic studies (Gifford, 1981). Reliably inferring the creators of traces (following GiffordGonzalez’s [1991] nested hierarchy of inference) requires both the use of relational analogy to identify the causal agency that created them and the description of formal attributes of those traces, including size, shape, location, orientation, and frequency. This is especially relevant given the generally hypothetical nature of causal relations between taphonomic processes and effects (Lyman, 1994). Binford (1981) argues that a causal relationship between a particular process and its trace must be established to build reliable actualistic models. Binford views this causal relationship as constant and unique, and once this relation is established, it allows us to recognize diagnostic An Actualistic Research Protocol How does one put this theory into practice, and conduct actualistic taphonomic research? Marean (1995) has outlined a research protocol for this, which is reiterated here, with the aim of providing examples of studies conducted addressing each step of the protocol. First, researchers use observations during naturalistic studies to establish unambiguous links between processes and the traces they produce on bones. Leading researchers focusing on this step of the protocol include Behrensmeyer (e.g. 1991), who studies variability in modern landscape bone assemblages; Blumenschine (e.g. 1986), who studies modern carnivore bone modification under naturalistic conditions; and O’Connell et al (e.g. 1992), who study butchery traces of modern hunter-gatherers in Tanzania. These studies often address ecological- and behavioral-level questions (following Gifford-Gonzalez’s [1991] nested hierarchy of inference), and the traces they study are often entire bone assemblages themselves. Second, an experimental study which controls the chosen parameters of the observed process to further refine our understanding of the link between process and trace is designed and implemented. The result is a robust bridging argument that can be used effectively in the deductive interpretation of archaeological traces. A 58 Pobiner & Braun pioneer of this step of the protocol is Marean himself (e.g. Marean & Spencer, 1991). Three of the five papers in this volume (Domínguez-Rodrigo & Egido; Pobiner & Braun; Potter) focus on the second step of this protocol. These studies often address actor-level questions, and the traces they study are often specific bone modifications, e.g. cutmarks or tooth marks. Third, the results of a naturalistic or experimental study are applied to the archaeological record. Again, Marean (e.g. Marean et al 1992; Marean & Kim 1988) and Blumenschine (e.g. 1995) are advocates and practitioners of this step of the protocol. Only one of the papers in this volume (Egeland & Byerly) addresses this third step of the protocol. This paper combines new data on experimentally-derived post encounter return rates with previously published data on marrow extraction to calculate composite return rates. They then apply these composite return rates to ethnoarchaeological bone transport data by the Hadza (Tanzania) and Kua (Botswana) hunter-gatherers and skeletal element data from two Oldowan archaeological sites, Olduvai Gorge and Peninj (Tanzania). Their results indicate that return rates and appendicular bone transport decisions in these modern foragers are not correlated. From this, they conclude that return rates are more productively applied to questions of carcass processing rather than carcass transport. To address questions of carcass processing they advocate the use of butchery mark data. Egeland & Byerly’s final conclusion leads us to our next main issue. Four of the five papers in this volume (DomínguezRodrigo & Egido; Pobiner & Braun; Potter; Thompson) use bone surface modifications as the particular trace they are investigating. It has been argued that bone surface modifications are more useful than other taphonomic traces, especially skeletal element and age profiles, in identifying diagnostic signature criteria of particular taphonomic agents or processes and avoiding equifinality (cf. Bartram & Marean, 1999; Marean, 1997; Pobiner & Blumenschine, 2003). Thompson’s paper, while not strictly actualistic, recognizes the importance of bone surface modification frequencies in zooarchaeological analyses. Furthermore, Thompson makes the point that direct comparison of frequencies of bone surface modifications between ex pe ri men ta l an d a rc ha eo lo gic al assemblages may be problematic. Specifically, she introduces a coding convention aimed at eliminating bone fragments heavily affected by postdepositional processes, which, by affecting cortical surface preservation, can depress the frequency of bone surface modifications in archaeological assemblages. This new protocol thus allows observed mark frequencies to more accurately reflect those originally present in a death assemblage, before diagnenetic changes which may have altered bone surfaces occurred. The mode of hominin carcass acquisition and the amount of meat available to them is still actively debated among Oldowan zooarchaeologists, even for well-preserved and well-studied sites like FLK Zinjanthropus (Bunn & Kroll, 1986; Bunn 2001; Binford 1988). Although cutmarks have figured prominently in discussions of Oldowan hominin foraging patterns for over twenty years (e.g. Bunn, 1981; Potts & Shipman, 1981), the ambiguity associated with their interpretation hinders their application. Three of the five papers in this volume 59 Applying Actualism middle range research: Binford, 1981) these are clearly not impermeable categories. (Domínguez-Rodrigo & Egido; Pobiner and Braun; Potter) directly address this critical issue by providing controlled experiments aimed specifically at using cutmarks as traces of hominin activity patterns. Pobiner & Braun test the hypothesis that cutmark frequency on limb bones is related to the amount of meat present before butchery, and therefore the timing of hominin access to carcasses (early versus late). Their experimental butchery data do not support this hypothesis. However, they find, as do Domínguez-Rodrigo & Egido, that cutmark frequency increases with the size of the bone being butchered. Potter’s paper demonstrates that the forces used during muscle tissue removal far exceed the minimum force required to actually create a cutmark. Each of these papers underscores the utility of controlled experimentation and specific hypothesis-testing to understanding of the behavior encoded in cutmarks on fossil bones. Actualism: Considerations Methodological Sample Size: The benefits of conducting experiments where specific variables are controlled and others manipulated in order to determine plausible cause and effect relationships cannot be underestimated in the investigation of the archaeological record. In experiments we often vary specific factors because we believe they are relevant to observations in the archaeological record. Increasing the variation in independent variables exponentially increases the need for larger sample sizes. As time and money is often a limiting factor in these experiments, the isolation of variables comes at the cost of smaller sample sizes. A major problem with small sample sizes is that archaeological patterns are not unchanging, immutable properties. Unlike physical or chemical data where certain processes consistently produce the same pattern (i.e. the interaction between a base and an acid), archaeological patterns are affected by behavioral flexibility. This is not a major methodological hurdle, but when viewing archaeological patterns there is the expectation of a certain degree of variation around a mean. Therefore what can appear to be a pattern in a small sample size can subsequently disappear when the sample size increases. This is evident in a study that critiqued the assumed relationship between the percentage of a type of cortical tool debitage in Oldowan assemblages and brain lateralization in early hominins (Pobiner Future Considerations Like all scientific endeavors, actualistic studies attempt to: “increase the in f o r ma t i o n al p o t e n t ia l o f ou r observations” (Binford, 1981: 22). However, as archaeology is a historical science, our “observations” are based on static objects rather than dynamic processes. We review the theoretical and conceptual goals future studies need to consider when conducting (and more importantly, applying) actualistic research. Here we categorize our considerations into methodological and theoretical perspectives. However, as the basis for actualistic research is the bridging of empirical observations with theoretical conditions (i.e. 60 Pobiner & Braun and replicability of our actualistic studies. In addition it is vital that adequate training standards with controlled actualisitc collections for recognizing and distinguishing traces are incorporated into an actualitic research agenda. 1999). Toth (1985) made the assertion that an asymmetric bimodality in the percentage of whole flakes showing cortex on one side of the flake represented the appearance of “handedness” among early hominins (see Toth, 1985; Pobiner, 1999 for a full description of the pattern and inference). Pobiner (1999: 91) noted that in a series of arc ha eo lo gi ca l an d e xpe ri me nt al assemblages that “[a]s the sample size increases, the proportion of right- to lefthanded flakes gets closer to 50:50.” This emphasizes the need to expand the role of actualistic studies by repeating experiments and bringing disparate actualistic datasets together to strengthen our inferences about the archaeological record Uniformity in the Experimental Method: As stated above, clearly one of the most important advances in actualistic studies will be made through studies that have larger sample sizes and control a greater number of variables. The independent replication of experiments is vital to a more secure connection between cause and effect in the archaeological and actualistic record. However, as recent attempts to compile datasets have shown, there is need to standardize the way in which experiments are conducted (Lupo and O’Connell, 2002). This problem is most explicitly addressed in Domínguez-Rodrigo (2002). Domínguez-Rodrigo (2002) itemizes various factors in a series of experiments conducted by several research teams to show that not only are independent variables significantly varied but dependent variables are also recorded differently. The result is a series of datasets that cannot be directly compared. Clearly, expanding our understanding of prehistoric butchery practices (or any other archaeological pattern) will rely heavily on the uniformity Actualism: Theoretical Considerations The Myth of Middle Range Research Actualism has had a clear impact on our understanding of zooarchaeological assemblages. The study of modern processes on bones and their resultant traces has opened new avenues of research into the diet and subsistence behaviors in the past. But the search for a greater understanding of archaeofaunas has also revealed that the association between assemblages of archaeological bones and past behaviors is far more complex than originally envisioned. As equifinalities are exposed it is clear that earlier attempts at actualism suffered from flaws in the behavioral interpretation of particular variables, e.g. Binford’s (1981) reverse utility curves. This does not affect the analytical importance of actualistic studies, but it does focus our attention on what it is about actualistic studies that make them vital to archaeological investigation. The specific techniques and methodologies developed and tested through actualistic studies are not as important as the development of underlying explanatory mechanisms. As Bettinger (1991:79) so aptly questions: “Would Binford’s arguments regarding butchering be any more or less compelling were it to turn out that the Nuniamiut never existed? Do analyses that apply the principles of butchering Binford has 61 Applying Actualism Actualism’s Assumption articulated depend on the logic of Binford’s reasoning or the accuracy of his factual observations?” This emphasizes Bettinger’s “myth of middle range theory.” A general assumption by many that conduct actualistic studies is that knowledge of the contemporary world is the key to understanding the past. However the most vital aspect of actualistic studies lies in the understanding between process and product. The recent understanding that reverse utility curves are the product of a myriad of biostratinomic and diagenetic factors (Bartram & Marean, 1999) does not undercut the importance of Binford’s study of the Nuniamiut. The importance of Binford’s study is the realization that the economic utility of skeletal parts affects the butchery practices of hunter-gatherer populations and the subsequent material residues of these practices. Despite the great promise reflected in current actualistic studies (such as those incorporated in this volume), the pitfalls associated with their direct application to the archaeological record must also be recognized. In such circumstances, actualistic studies should not be expected to accomplish the impossible goal of reproducing the archaeological record, but rather to provide a paradigmatic guide to the interpretation of the archaeological record. Archaeology will always be a historical science. No amount of actualistic studies will ever change the fact that the processes we are really interested in cannot be observed. But that does not mean that we cannot develop inferences about the past by understanding the dynamics of modern day processes. The most cited criticism of actualism is the fact that in order to conduct actualistic studies you must assume a temporal and spatial invariance in factors affecting the formation of the archaeological record (Gould 1980). This is the classic uniformitarian assumption that the past and the present are the same at least in terms of the kinds of processes that occur, although not necessarily in terms of the intensity of those processes (Lyman, 1994). This critique is associated with a separate but related suggestion that actualism limits the study of the archaeological record to those processes that occurred in the present. Although many arguments assume that actualism is the search for immanent properties, as opposed to essential dynamics of process and pattern, there is some merit to expanding our conception of the past based on information derived soley from the archaeological record. Especially when extrapolating modern processes into the deep past (i.e. timing of early hominin access to carcasses), there is the very real possibility of a fundamental difference in the kind of processes to which archaeofaunal assemblages are exposed. The real danger in dismissing the possibility of processes with no modern analogue as having some explanatory power for the archaeological record is overzealous adherence to modern processes. When the archaeological record does not conform to the actualistic record, sometimes we assume it is because our knowledge of modern process dynamics is insufficient. This provides the impetus for an increasingly specific study of modern processes when there is the possibility that a process that no longer exists explains the 62 Pobiner & Braun of behavior. Yet an inherent assumption in the experimental design of these studies is that butchery practices in the past are similar enough to modern ones that the majority of the possible behavioral variation will be displayed by a modern human. This introduces an inordinate amount of possible behavioral variability (e.g. butcher exhaustion through the course of a butchery event; idiosyncratic nature of a particular butcher’s technique; cultural construction of “how” to butcher an animal). Although these are concerns they also emphasize the need for actualistic studies to focus on isolating causation rather than making formal analogies (pattern recognition) between modern products (which are likely affected by behavioral flexibility) and archaeological products. most amount of variation in the archaeological record. The study of the past clearly requires the incorporation of actualism for a fuller understanding of the archaeological record, yet it may be necessary for future experimental models to accept that the archaeological patterns cannot be fully explained by the present (Kitts, 1977). Actualism’s Compromise Actualistic studies capitalize on the ability to observe modern processes and manipulate variables to determine their effect on the material record. Actualistic studies need to maximize realism and precision, while minimizing generality. Especially in the study of butchery practices, the number of variables that could plausibly effect the dependent variables (usually bone surface modifications) is staggering (e.g. tool type, tool raw material, butcher experience, number of butchers, size of carcass, condition of carcass etc.). To maximize the precision of the recording of all of these variables (and then manipulating them) would require an experiment so controlled that it would represent an unrealistic scenario (Levins, 1966). Future actualistic research should recognize that only an increase in precision will allow true comparison between studies. If we are to develop probabilistic inferences about the formation of the archaeological record we need to know the variables that influence that formation. Most butchery experiments fall into a category of “imitative experiments” (Pelcin 1996), in that the archaeological record is imitated by modern peoples in an attempt to observe the processes that belie the production of traces Actualism: A Prescription The papers in this volume represent a current trend in actualistic research as it pertains to an understanding of butchery activities by early hominins. However, these studies are also relevant to the broader realm of actualistic research because they stress the importance of both controlled experimental design and the need for repeated experiments testing the same relationships between modern processes and traces. Although some patterns in the archaeological record may not be amenable to actualistic investigation, only continued experimentation will reveal what we can know about the past. Actualistic research is sometimes considered a methodological sub-text of contemporary archaeological investigation of the past. We would argue that rigorous experimental protocols and focused (and well-funded) actualistic 63 Applying Actualism interpretations. Current Anthropology, 29: 123‑135. Blumenschine, R. J. (1986). Carcass consumption sequences and the archaeological distinction of hunting and scavenging. Journal of Human Evolution, 15: 639-659. Blumenshine, R. J. (1995). Percussion marks, tooth marks, and experimental determinations of the timing of hominid and carnivore access to long bones at FLK Zinjanthropus, Olduvai Gorge, Tanzania. Journal of Human Evolution, 29: 21-51. Bunn, H. T. (1981). Archaeological evidence for meat‑eating by Plio‑Pleistocene hominids from Koobi Fora and Olduvai Gorge. Nature, 291: 547‑577. Bunn, H. T. (2001). Hunting, power scavenging, and butchering by Hadza foragers and by PlioPleistocene Homo. In (Stanford, C. B., & Bunn, H. T., eds.) Meat Eating and Human Evolution. Oxford: Oxford University Press, pp. 199-281. Bunn, H.T. & Kroll, E.M. (1986). Systematic butchery by Plio/Pleistocene hominids at Olduvai Gorge, Tanzania. Current Anthropology, 27: 431‑452. Gifford, D. (1981). Taphonomy and paleoecology: a critical review of archaeology’s sister disciplines. In (M. B. Schiffer, ed) Advances in Archaeological Method and Theory vol. 4, pp. 365-438. New York: Academic Press. Gifford-Gonzalez, D. (1989). Modern analogues: developing an interpretive framework. In (Bonnichsen, R. & Sorg, M. H., eds.) Bone Modification, pp. 43-52. Orono: University of Maine Center for the Study of the First Americans. Gould, R. (1980) Living Archaeology. Cambridge, Cambridge University Press. Kitts, D. B. (1977) The Structure of Geology. Dallas, Southern Methodist University Press. Levins, R. (1966) The strategy of model building in population biology. American Scientist, 54: 421431. Lyman, R. L. (1994). Vertebrate Taphonomy. Cambridge: Cambridge University Press. Marean, C. W. (1995). Of taphonomy and zooarchaeology. Evolutionary Anthropology, 4: 64-72. Marean, C. W. (1997). Hunter-gatherer foraging strategies in tropical grasslands: model building and testing in the East African Middle and Later Stone Age. Journal of Anthropological Archaeology, 16: 189-225. Marean, C.W. & Kim, S.Y. (1998). Mousterian largemammal remains from Kobeh Cave: behavioral implications for Neanderthals and early modern humans. Current Anthropology, 39: S79-S113. experiments are at least as important as the discovery of new archaeological materials. We hope this special issue will serve as an impetus for an expanding interest in actualism as a powerful explanatory tool for the interpretation of archaeological patterns. Acknowledgements We would like to thank to all of the participants in our symposium at the 2004 Society for American Archaeology meetings, from which this volume’s contents were drawn. We would especially like to thank the participants in this volume for their contributions, as well as Manuel Domínguez-Rodrigo and Travis Pickering as the editors of the Journal of Taphonomy, for assistance and patience with us as guest editors. We are also grateful to the reviewers of these papers for providing useful and timely critiques. Finally, we are grateful to Rob Blumenschine and Charles Egeland for providing thoughtful comments on this paper. References Bartram, L.E., Jr. & Marean, C.W. (1999). 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