- Email: [email protected]
Archaeological inference and Oldowan behavior
Journal of Human Evolution 51 (2006) 106e108
News and Views
Archaeological inference and Oldowan behavior David R. Braun a,*, Joanne C. Tactikos a, Joseph V. Ferraro b, J.W.K. Harris a a
Department of Anthropology, Rutgers University, 131 George Street, New Brunswick, NJ 08901, USA b Department of Anthropology, University of California, Los Angeles, CA 90095-1553, USA Received 16 March 2006; accepted 3 April 2006
Keywords: Oldowan; Flake recovery rate; Experimental archaeology; Olduvai
‘‘Understanding does not come self-evidently from the material remains.’’ Amick and Mauldin (1989) The archaeological record represents a complex interaction between behavioral variation, natural processes of burial, and the results of archaeological recovery techniques. Kimura (2006) defends the use of an assemblage composition variable, flake recovery rate (FRR). Kimura (2006) suggests that our previous experimental work (Braun et al., 2005) is not relevant to the study of Olduvai archaeological assemblages. We believe Kimura’s conclusion is based on a misinterpretation of our experiments. Inferences about the meaning of archaeological data cannot be derived from the archaeological data itself (Amick and Mauldin, 1989). Nor can these inferences be the result of an assumed relationship between empirical data and presumed behavior (Kelly, 1994). Data collected from the study of stone tools in archaeological sites requires an independent referential framework to develop meaningful inferences from these static traces of hominin behavior. Experimental archaeology and the paradigm of middle range research (Binford, 1981) provide a method for assessing equifinality between archaeological products and dynamic processes in the past. We believe Kimura’s response stems from a conflation of the experimental method and the experimental model that
* Corresponding author. Tel.: þ1 908 353 5370; fax: þ1 908 353 5367. E-mail addresses: [email protected] (D.R. Braun), tactix@eden. rutgers.edu (J.C. Tactikos), [email protected] (J.V. Ferraro), jwharris@ rci.rutgers.edu (J.W.K. Harris). 0047-2484/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jhevol.2006.04.002
Bettinger (1991) termed the ‘‘myth of middle range research.’’ Here we review why our experimental method provides a model that poses problems for the application of FRR values to the archaeological record at Olduvai. Experiments and archaeology An experimental research agenda is used to investigate ambiguity and equifinality in measurement techniques. In this sense, our study (Braun et al., 2005) was intended to describe and understand the relationship between a static archaeological product (flake recovery rates) and a dynamic process (core reduction). As such we have determined that there is a relationship between the original size of a core being reduced and the resulting FRR in an assemblage of tools. Furthermore we have developed an explanatory mechanism (flake scar erasure rates) that suggests that this relationship is a product of the geometry of core size and knapping behaviors. Kimura states that this determination is not relevant to the interpretation of hominin behavior at Olduvai because core mass values in our experiment were not similar to core mass values in the Olduvai archaeological data set. Although this particular criticism is actually unfounded (see below) it is reflective of Kimura’s misunderstanding of an experimental research design. In Binford’s (1978) study of Nunamuit hunter-gathers, there were many formal differences between these arctic foragers, who used metal knives and snowmobiles, and Paleolithic hominins. However, Binford’s observations allowed the formulation of hypotheses about hunter-gatherer mobility and material traces, as well as the governing of faunal exploitation via the economic importance of skeletal portions.
D.R. Braun et al. / Journal of Human Evolution 51 (2006) 106e108
Middle range research is the formulation of a relationship between a dynamic process and static product. The experimental method develops an empirical scenario where variables can be controlled and the relationship between these variables can be discerned. The resulting experimental model is the inference about the causal mechanism between two variables and is the basis of a relational analogy with the archaeological record (Gifford-Gonzalez, 1991). Our experiments have developed a model that explains why larger cobbles inherently produce assemblages with higher FRR values. Kimura’s rejection of this explanatory relationship as having relevance for the interpretation of archaeological data at Olduvai further underscores a misunderstanding of the differences between experimental methods and models. Experimental archaeology is never intended to recreate the archaeological record. Indeed, if this were the intention, then we would remain ignorant about any system that occurred in the past but that is no longer operating in the modern world. For Oldowan archaeologists whose subject of interest is in the very remote past, this issue would pose a particularly daunting obstacle. Experimental archaeology develops a paradigmatic guide to the interpretation of the archaeological record. We have pointed out that the continuous (not ordinal) variation in FRR in the Olduvai archaeological record is inversely correlated with the original size of cores. Kimura suggests that this finding is not relevant because the experimental FRRs are consistently greater than 100 and the Olduvai record shows values lower than 100. Our experiments represent a single flintknapping event, where all products of that event are recovered and analyzed. With the possible exception of the unusual preservation at the Lokalalei 2C locality in the Nachukui Formation (Roche et al., 1999), no Oldowan occurrence should have FRR values similar to our experimental assemblages. Archaeological assemblages represent a palimpsest of multiple episodes of stone artifact production and use. The resulting assemblages are modified by hominin transport behaviors, hydraulic transport behaviors, trampling, differential levels of recovery, and a host of other site formation processes. However, prior to any of these processes, assemblages that are made from small cobbles will have higher FRRs (greater flake scar erasure rate) and those made from larger cobbles will have lower FRRs (lower flake scar erasure rate). Therefore FRR values cannot be used for direct comparison between assemblages that may have varying initial core sizes.
of the ‘‘flake scar erasure rate.’’ As cores continue to be reduced, this flake scar erasure rate decreases (i.e., the surface area of the core decreases and the likelihood of flake scar overlap increases; see Braun et al., 2005: Fig. 5). However, our residual core rates are also significantly negatively correlated with FRR values (r ¼ 0.699, p < 0.001). Kimura also criticizes our use of the Pearson product moment correlation because of the small sample sizes and non-normal distribution of the data. However, non-parametric tests result in even higher correlation coefficients for both initial core mass (Spearman’s rho r ¼ 0.870, p < 0.001) and residual core mass (Spearman’s rho r ¼ 0.705, p < 0.001). Finally, Kimura suggests that our experimental data set was not relevant to the Olduvai data set because of ‘‘a large gap between the size of initial cobbles in Braun et al.’s experiments and that of residual cores in the Olduvai sample’’ (Kimura, 2006: 103). Yet the distributions of ‘‘residual’’ core mass from our experimental sample and that of the Olduvai sample, which Kimura suggests is a more relevant comparison, are very similar (Fig. 1). Experimental archaeology in Oldowan studies Kimura (2006) states that the experiments we conducted were not relevant to archaeological collections and therefore cannot be used in the formation of inferences about Oldowan hominins. This suggests that experimental archaeology has little or no place in developing an understanding of Oldowan hominin behavior. Ethnographic and experimental studies are at the forefront of developing a greater understanding of Oldowan hominin behavior by generating empirical data that can be used to test behavioral models (e.g., Toth, 1991; Toth et al., 1993; Sahnouni et al., 1997; Stout, 2002). The continuously expanding number of variables employed in the study of Paleolithic stone artifacts requires a concurrent experimental research paradigm to determine the meaning of these variables. This issue is even more important given the higher-order inferences extrapolated from analysis of stone tools (Bamforth, 1990; Wurz, 1999). In order to solidify arguments about the past, it is necessary to create explicit Experimental Data "Residual" Core Mass (Braun et al. 2005) Olduvai Beds I and II sample
2000-2249 g.
Methodological issues
1500-1749 g.
Mass
Kimura does make some methodological notes that are worth investigating. Kimura questions the applicability of the correlation between cobble size and FRR values because the experimental data set uses ‘‘initial core size’’ and the archaeological data set is derived from a ‘‘residual core size.’’ In other words our experimental model is based on the cobbles prior to reduction and the archaeological data represents already knapped cores. We used ‘‘initial core size’’ in the development of the model because it allows for the investigation
107
1000-1249 g. 500-749 g. 0-249 g. 0
10
20
30
40
50
60
70
Percent of Assemblage Fig. 1. Percentages of core mass from experimental and archaeological assemblages.
108
D.R. Braun et al. / Journal of Human Evolution 51 (2006) 106e108
inferential linkages between each successively higher level of explanation in the archaeological record (Amick, 1994). Inferential linkages are hierarchical in that inferences between ecological context and actor are necessarily dependant on solid inferential linkages from the archaeological trace through the actor (Gifford-Gonzalez, 1991). The use of variables that are employed without an experimental research design that defines and interprets the influences on these variables is testament to Carr and Bradbury’s (2001) growing ‘‘data-theory gap’’ in lithic analysis. A renewed emphasis on the reliability of inferences about behavior from lithic data should be the cornerstone of new rounds of research on the Paleolithic (Bamforth, 1991; Kuhn, 1991; Amick, 1994). Conclusion As we stated in our original paper, we believe that some of the conclusions that Kimura (1999, 2002) has made concerning hominin transport behaviors may be true. Indeed many of her observations about the relationship between Oldowan archaeological data and hominin biological evolution (Kimura, 2002: Fig. 17) are similar to conclusions based on analyses of assemblages at Koobi Fora (Rogers et al., 1994: Fig. 8). However, the intention of our initial paper was to call into question the validity of using FRR values to make higher-order inferences about Oldowan behavior because of the clear relationship between FRR values and initial core size. Kimura has offered no further experimental data to suggest that such a relationship does not exist. Further, her claims that our experiments are not ‘‘relevant’’ to archaeological collections stems from a misunderstanding of experimental archaeology. References Amick, D.S., 1994. Technological organization and the structure of inference in lithic analysis: An examination of Folsom hunting behavior in the American southwest. In: Carr, P.J. (Ed.), The Organization of North American Prehistoric Chipped Stone Tool Technologies. International Monographs in Prehistory, Ann Arbor, pp. 9e34. Amick, D.S., Mauldin, R.P., 1989. Comments on Sullivan and Rozen’s ‘‘Debitage analysis and archaeological interpretations.’’ Am. Antiq. 54, 166e175. Bamforth, D.B., 1990. Settlement, raw material, and lithic procurement in the central Mojave Desert. J. Anthropol. Archaeol. 9, 70e104.
Bamforth, D.B., 1991. Technological organization and hunter-gatherer land use: a California example. Am. Antiq. 56, 216e234. Binford, L.R., 1978. Nunamuit Ethnoarchaeology. Academic Press, New York. Binford, L.R., 1981. Bones: Ancient Men and Modern Myths. Academic Press, New York. Bettinger, R., 1991. Hunter-Gatherers: Archaeological and Evolutionary Theory. Plenum Press, New York. Braun, D.R., Tactikos, J.C., Ferraro, J.V., Harris, J.W.K., 2005. Flake recovery rates and inferences of Oldowan hominin behavior: a response to Kimura 1999, 2002. J. Hum. Evol. 48, 525e531. Carr, P.J., Bradbury, A.P., 2001. Flake debris analysis, levels of production, and the organization of technology. In: Andrefsky Jr, W. (Ed.), Lithic Debitage: Context, Form, Meaning. University of Utah Press, Salt Lake City, pp. 126e146. Gifford-Gonzalez, D., 1991. Bones are not enough: analogues, knowledge, and interpretive strategies in zooarchaeology. J. Anthropol. Archaeol. 10, 215e254. Kelly, R.L., 1994. Some thoughts on future directions in the study of stone tool technological organization. In: Carr, P.J. (Ed.), The Organization of North American Prehistoric Chipped Stone Tool Technologies. International Monographs in Prehistory, Ann Arbor, pp. 132e136. Kimura, Y., 1999. Tool-using strategies by early hominids at Bed II, Olduvai Gorge, Tanzania. J. Hum. Evol. 37, 807e831. Kimura, Y., 2002. Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge. J. Hum. Evol. 43, 291e321. Kimura, Y., 2006. On the critique of flake recovery rate and behavioral inference for early hominids: A reply to Braun et al. (2005). J. Hum. Evol. 51, 102e105. Kuhn, S.L., 1991. ‘‘Unpacking’’ reduction: lithic raw material economy in the Mousterian of west-central Italy. J. Anthropol. Archaeol. 10, 76e106. Roche, H., Delagnes, A., Brugal, J.P., Feibel, C., Kibunjia, M., Mourre, V., Texier, P.J., 1999. Early hominid stone tool production and technical skill 2.34 Myr ago in west Turkana, Kenya. Nature 399, 57e60. Rogers, M.J., Harris, J.W.K., Feibel, C.S., 1994. Changing patterns of land-use by Plio-Pleistocene hominids in the Lake Turkana Basin. J. Hum. Evol. 27, 139e158. Sahnouni, M., Schick, K., Toth, N., 1997. An experimental investigation into the nature of faceted limestone ‘‘spheroids’’ in the Early Palaeolithic. J. Archaeol. Sci. 24, 701e713. Stout, D., 2002. Skill and cognition in stone tool productiondan ethnographic case study from Irian Jaya. Curr. Anthropol. 43, 693e722. Toth, N., 1991. Importance of experimental replicative and functional studies in Palaeolithic archaeology. In: Clark, J.D. (Ed.), Cultural Beginnings: Approaches to Understanding Early Hominid Life-Ways in the African Savanna. Rudolf Habelt Verlag, Bonn, pp. 109e124. Toth, N., Savage-Rumbaugh, E.S., Sevcik, R.A., Rumbaugh, D.M., Schick, K.D., 1993. Pan the tool-maker: investigations into the stone tool-making and tool-using capabilities of a bonobo (Pan paniscus). J. Archaeol. Sci. 20, 81e91. Wurz, S., 1999. The Howiesons Poort backed artefacts from Klasies river: an argument for symbolic behaviour. S. Afr. Archaeol. Bull. 54, 38e50.
News and Views
Archaeological inference and Oldowan behavior David R. Braun a,*, Joanne C. Tactikos a, Joseph V. Ferraro b, J.W.K. Harris a a
Department of Anthropology, Rutgers University, 131 George Street, New Brunswick, NJ 08901, USA b Department of Anthropology, University of California, Los Angeles, CA 90095-1553, USA Received 16 March 2006; accepted 3 April 2006
Keywords: Oldowan; Flake recovery rate; Experimental archaeology; Olduvai
‘‘Understanding does not come self-evidently from the material remains.’’ Amick and Mauldin (1989) The archaeological record represents a complex interaction between behavioral variation, natural processes of burial, and the results of archaeological recovery techniques. Kimura (2006) defends the use of an assemblage composition variable, flake recovery rate (FRR). Kimura (2006) suggests that our previous experimental work (Braun et al., 2005) is not relevant to the study of Olduvai archaeological assemblages. We believe Kimura’s conclusion is based on a misinterpretation of our experiments. Inferences about the meaning of archaeological data cannot be derived from the archaeological data itself (Amick and Mauldin, 1989). Nor can these inferences be the result of an assumed relationship between empirical data and presumed behavior (Kelly, 1994). Data collected from the study of stone tools in archaeological sites requires an independent referential framework to develop meaningful inferences from these static traces of hominin behavior. Experimental archaeology and the paradigm of middle range research (Binford, 1981) provide a method for assessing equifinality between archaeological products and dynamic processes in the past. We believe Kimura’s response stems from a conflation of the experimental method and the experimental model that
* Corresponding author. Tel.: þ1 908 353 5370; fax: þ1 908 353 5367. E-mail addresses: [email protected] (D.R. Braun), tactix@eden. rutgers.edu (J.C. Tactikos), [email protected] (J.V. Ferraro), jwharris@ rci.rutgers.edu (J.W.K. Harris). 0047-2484/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.jhevol.2006.04.002
Bettinger (1991) termed the ‘‘myth of middle range research.’’ Here we review why our experimental method provides a model that poses problems for the application of FRR values to the archaeological record at Olduvai. Experiments and archaeology An experimental research agenda is used to investigate ambiguity and equifinality in measurement techniques. In this sense, our study (Braun et al., 2005) was intended to describe and understand the relationship between a static archaeological product (flake recovery rates) and a dynamic process (core reduction). As such we have determined that there is a relationship between the original size of a core being reduced and the resulting FRR in an assemblage of tools. Furthermore we have developed an explanatory mechanism (flake scar erasure rates) that suggests that this relationship is a product of the geometry of core size and knapping behaviors. Kimura states that this determination is not relevant to the interpretation of hominin behavior at Olduvai because core mass values in our experiment were not similar to core mass values in the Olduvai archaeological data set. Although this particular criticism is actually unfounded (see below) it is reflective of Kimura’s misunderstanding of an experimental research design. In Binford’s (1978) study of Nunamuit hunter-gathers, there were many formal differences between these arctic foragers, who used metal knives and snowmobiles, and Paleolithic hominins. However, Binford’s observations allowed the formulation of hypotheses about hunter-gatherer mobility and material traces, as well as the governing of faunal exploitation via the economic importance of skeletal portions.
D.R. Braun et al. / Journal of Human Evolution 51 (2006) 106e108
Middle range research is the formulation of a relationship between a dynamic process and static product. The experimental method develops an empirical scenario where variables can be controlled and the relationship between these variables can be discerned. The resulting experimental model is the inference about the causal mechanism between two variables and is the basis of a relational analogy with the archaeological record (Gifford-Gonzalez, 1991). Our experiments have developed a model that explains why larger cobbles inherently produce assemblages with higher FRR values. Kimura’s rejection of this explanatory relationship as having relevance for the interpretation of archaeological data at Olduvai further underscores a misunderstanding of the differences between experimental methods and models. Experimental archaeology is never intended to recreate the archaeological record. Indeed, if this were the intention, then we would remain ignorant about any system that occurred in the past but that is no longer operating in the modern world. For Oldowan archaeologists whose subject of interest is in the very remote past, this issue would pose a particularly daunting obstacle. Experimental archaeology develops a paradigmatic guide to the interpretation of the archaeological record. We have pointed out that the continuous (not ordinal) variation in FRR in the Olduvai archaeological record is inversely correlated with the original size of cores. Kimura suggests that this finding is not relevant because the experimental FRRs are consistently greater than 100 and the Olduvai record shows values lower than 100. Our experiments represent a single flintknapping event, where all products of that event are recovered and analyzed. With the possible exception of the unusual preservation at the Lokalalei 2C locality in the Nachukui Formation (Roche et al., 1999), no Oldowan occurrence should have FRR values similar to our experimental assemblages. Archaeological assemblages represent a palimpsest of multiple episodes of stone artifact production and use. The resulting assemblages are modified by hominin transport behaviors, hydraulic transport behaviors, trampling, differential levels of recovery, and a host of other site formation processes. However, prior to any of these processes, assemblages that are made from small cobbles will have higher FRRs (greater flake scar erasure rate) and those made from larger cobbles will have lower FRRs (lower flake scar erasure rate). Therefore FRR values cannot be used for direct comparison between assemblages that may have varying initial core sizes.
of the ‘‘flake scar erasure rate.’’ As cores continue to be reduced, this flake scar erasure rate decreases (i.e., the surface area of the core decreases and the likelihood of flake scar overlap increases; see Braun et al., 2005: Fig. 5). However, our residual core rates are also significantly negatively correlated with FRR values (r ¼ 0.699, p < 0.001). Kimura also criticizes our use of the Pearson product moment correlation because of the small sample sizes and non-normal distribution of the data. However, non-parametric tests result in even higher correlation coefficients for both initial core mass (Spearman’s rho r ¼ 0.870, p < 0.001) and residual core mass (Spearman’s rho r ¼ 0.705, p < 0.001). Finally, Kimura suggests that our experimental data set was not relevant to the Olduvai data set because of ‘‘a large gap between the size of initial cobbles in Braun et al.’s experiments and that of residual cores in the Olduvai sample’’ (Kimura, 2006: 103). Yet the distributions of ‘‘residual’’ core mass from our experimental sample and that of the Olduvai sample, which Kimura suggests is a more relevant comparison, are very similar (Fig. 1). Experimental archaeology in Oldowan studies Kimura (2006) states that the experiments we conducted were not relevant to archaeological collections and therefore cannot be used in the formation of inferences about Oldowan hominins. This suggests that experimental archaeology has little or no place in developing an understanding of Oldowan hominin behavior. Ethnographic and experimental studies are at the forefront of developing a greater understanding of Oldowan hominin behavior by generating empirical data that can be used to test behavioral models (e.g., Toth, 1991; Toth et al., 1993; Sahnouni et al., 1997; Stout, 2002). The continuously expanding number of variables employed in the study of Paleolithic stone artifacts requires a concurrent experimental research paradigm to determine the meaning of these variables. This issue is even more important given the higher-order inferences extrapolated from analysis of stone tools (Bamforth, 1990; Wurz, 1999). In order to solidify arguments about the past, it is necessary to create explicit Experimental Data "Residual" Core Mass (Braun et al. 2005) Olduvai Beds I and II sample
2000-2249 g.
Methodological issues
1500-1749 g.
Mass
Kimura does make some methodological notes that are worth investigating. Kimura questions the applicability of the correlation between cobble size and FRR values because the experimental data set uses ‘‘initial core size’’ and the archaeological data set is derived from a ‘‘residual core size.’’ In other words our experimental model is based on the cobbles prior to reduction and the archaeological data represents already knapped cores. We used ‘‘initial core size’’ in the development of the model because it allows for the investigation
107
1000-1249 g. 500-749 g. 0-249 g. 0
10
20
30
40
50
60
70
Percent of Assemblage Fig. 1. Percentages of core mass from experimental and archaeological assemblages.
108
D.R. Braun et al. / Journal of Human Evolution 51 (2006) 106e108
inferential linkages between each successively higher level of explanation in the archaeological record (Amick, 1994). Inferential linkages are hierarchical in that inferences between ecological context and actor are necessarily dependant on solid inferential linkages from the archaeological trace through the actor (Gifford-Gonzalez, 1991). The use of variables that are employed without an experimental research design that defines and interprets the influences on these variables is testament to Carr and Bradbury’s (2001) growing ‘‘data-theory gap’’ in lithic analysis. A renewed emphasis on the reliability of inferences about behavior from lithic data should be the cornerstone of new rounds of research on the Paleolithic (Bamforth, 1991; Kuhn, 1991; Amick, 1994). Conclusion As we stated in our original paper, we believe that some of the conclusions that Kimura (1999, 2002) has made concerning hominin transport behaviors may be true. Indeed many of her observations about the relationship between Oldowan archaeological data and hominin biological evolution (Kimura, 2002: Fig. 17) are similar to conclusions based on analyses of assemblages at Koobi Fora (Rogers et al., 1994: Fig. 8). However, the intention of our initial paper was to call into question the validity of using FRR values to make higher-order inferences about Oldowan behavior because of the clear relationship between FRR values and initial core size. Kimura has offered no further experimental data to suggest that such a relationship does not exist. Further, her claims that our experiments are not ‘‘relevant’’ to archaeological collections stems from a misunderstanding of experimental archaeology. References Amick, D.S., 1994. Technological organization and the structure of inference in lithic analysis: An examination of Folsom hunting behavior in the American southwest. In: Carr, P.J. (Ed.), The Organization of North American Prehistoric Chipped Stone Tool Technologies. International Monographs in Prehistory, Ann Arbor, pp. 9e34. Amick, D.S., Mauldin, R.P., 1989. Comments on Sullivan and Rozen’s ‘‘Debitage analysis and archaeological interpretations.’’ Am. Antiq. 54, 166e175. Bamforth, D.B., 1990. Settlement, raw material, and lithic procurement in the central Mojave Desert. J. Anthropol. Archaeol. 9, 70e104.
Bamforth, D.B., 1991. Technological organization and hunter-gatherer land use: a California example. Am. Antiq. 56, 216e234. Binford, L.R., 1978. Nunamuit Ethnoarchaeology. Academic Press, New York. Binford, L.R., 1981. Bones: Ancient Men and Modern Myths. Academic Press, New York. Bettinger, R., 1991. Hunter-Gatherers: Archaeological and Evolutionary Theory. Plenum Press, New York. Braun, D.R., Tactikos, J.C., Ferraro, J.V., Harris, J.W.K., 2005. Flake recovery rates and inferences of Oldowan hominin behavior: a response to Kimura 1999, 2002. J. Hum. Evol. 48, 525e531. Carr, P.J., Bradbury, A.P., 2001. Flake debris analysis, levels of production, and the organization of technology. In: Andrefsky Jr, W. (Ed.), Lithic Debitage: Context, Form, Meaning. University of Utah Press, Salt Lake City, pp. 126e146. Gifford-Gonzalez, D., 1991. Bones are not enough: analogues, knowledge, and interpretive strategies in zooarchaeology. J. Anthropol. Archaeol. 10, 215e254. Kelly, R.L., 1994. Some thoughts on future directions in the study of stone tool technological organization. In: Carr, P.J. (Ed.), The Organization of North American Prehistoric Chipped Stone Tool Technologies. International Monographs in Prehistory, Ann Arbor, pp. 132e136. Kimura, Y., 1999. Tool-using strategies by early hominids at Bed II, Olduvai Gorge, Tanzania. J. Hum. Evol. 37, 807e831. Kimura, Y., 2002. Examining time trends in the Oldowan technology at Beds I and II, Olduvai Gorge. J. Hum. Evol. 43, 291e321. Kimura, Y., 2006. On the critique of flake recovery rate and behavioral inference for early hominids: A reply to Braun et al. (2005). J. Hum. Evol. 51, 102e105. Kuhn, S.L., 1991. ‘‘Unpacking’’ reduction: lithic raw material economy in the Mousterian of west-central Italy. J. Anthropol. Archaeol. 10, 76e106. Roche, H., Delagnes, A., Brugal, J.P., Feibel, C., Kibunjia, M., Mourre, V., Texier, P.J., 1999. Early hominid stone tool production and technical skill 2.34 Myr ago in west Turkana, Kenya. Nature 399, 57e60. Rogers, M.J., Harris, J.W.K., Feibel, C.S., 1994. Changing patterns of land-use by Plio-Pleistocene hominids in the Lake Turkana Basin. J. Hum. Evol. 27, 139e158. Sahnouni, M., Schick, K., Toth, N., 1997. An experimental investigation into the nature of faceted limestone ‘‘spheroids’’ in the Early Palaeolithic. J. Archaeol. Sci. 24, 701e713. Stout, D., 2002. Skill and cognition in stone tool productiondan ethnographic case study from Irian Jaya. Curr. Anthropol. 43, 693e722. Toth, N., 1991. Importance of experimental replicative and functional studies in Palaeolithic archaeology. In: Clark, J.D. (Ed.), Cultural Beginnings: Approaches to Understanding Early Hominid Life-Ways in the African Savanna. Rudolf Habelt Verlag, Bonn, pp. 109e124. Toth, N., Savage-Rumbaugh, E.S., Sevcik, R.A., Rumbaugh, D.M., Schick, K.D., 1993. Pan the tool-maker: investigations into the stone tool-making and tool-using capabilities of a bonobo (Pan paniscus). J. Archaeol. Sci. 20, 81e91. Wurz, S., 1999. The Howiesons Poort backed artefacts from Klasies river: an argument for symbolic behaviour. S. Afr. Archaeol. Bull. 54, 38e50.