- Email: [email protected]
The symmetry of handaxes from the Danjiangkou Reservoir Region (central China): A methodological consideration
Quaternary International 400 (2016) 65e72
Contents lists available at ScienceDirect
Quaternary International journal homepage: www.elsevier.com/locate/quaint
The symmetry of handaxes from the Danjiangkou Reservoir Region (central China): A methodological consideration Hao Li a, *, Kathleen Kuman a, b, Chaorong Li c a
School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg WITS 2050, South Africa Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg WITS 2050, South Africa c Key Laboratory of Vertebrate Evolution and Human Origins & Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing 100044, China b
a r t i c l e i n f o
a b s t r a c t
Article history: Available online 10 June 2015
In this paper, we present a three-dimensional (3D) quantitative approach to measure the degree of symmetry of handaxes from the Danjiangkou Reservoir Region (DRR), central China. Our analysis provides not only information on the bilateral symmetry, as most previous studies have done, but also on the symmetry of the profile view. The results show that the overall degree of symmetry of handaxes in plan view is much higher than for profile views in the DRR assemblages. However, the range of values for deviation from absolute symmetry for each specimen indicates that both plan and profile views possess great variability in symmetry. Comparisons of handaxes from two terraces (the Middle Pleistocene Terrace 3 and the early Late Pleistocene Terrace 2) demonstrate that the degree of symmetry did not increase over time in these two samples. Both the type of blank and the type of shaping play roles in determining the final degree of symmetry of the DRR handaxes. According to these results, we argue that there is no strictly imposed final symmetrical shape for the DRR handaxes, and the degree of symmetry is most likely related to some basic factors (e.g., bilateral and bifacial shaping and blank types). However, although a mental template for a preferred end product is absent, a conceptual standardization did indeed exist. © 2015 Elsevier Ltd and INQUA. All rights reserved.
Keywords: Danjiangkou Reservoir Region Acheulean Handaxe 3D scanning Symmetry Mental template
1. Introduction Symmetry is a well-known characteristic of Acheulean handaxes, and various interpretations of why there is an imposed symmetrical form have been proposed by researchers. Some consider that basic factors, such as the size and shape of raw materials, the blank form, and the bilateral and/or bifacial flaking strategy, are linked to the symmetry of handaxes (Jones, 1979, 1994; Davidson and Noble, 1993; Ashton and McNabb, 1994; White, 1998; McPherron, 2000), while others think that functional adaptation, especially increased requirements for cutting and chopping in the Acheulean, would be the main reason for symmetry (Jones, 1980; Mitchell, 1996; Simao, 2002; Machin et al., 2007). In addition, some researchers argue that we should go far beyond these analyses and search for reasons in the social or cognitive context, e.g., strong social communication and learning (Mithen, 1994), sexual selection (Kohn and Mithen, 1999), aesthetic or symbolic sense (Pelegrin, 1993; Edwards, 2001; Reber, 2002; Pope et al., 2006; * Corresponding author. E-mail address: [email protected] (H. Li). http://dx.doi.org/10.1016/j.quaint.2015.05.033 1040-6182/© 2015 Elsevier Ltd and INQUA. All rights reserved.
Hodgson, 2010, 2011), and cognitive ability (Wynn, 1995, 2000, 2002; Shipton et al., 2013; Hodgson, 2015). No matter which explanation is preferred, they are all based on a conventional belief that symmetry of handaxes genuinely exists and can be applied not only to individual classic specimens, but also to handaxes in entire assemblages. However, we should bear in mind that this kind of belief is mainly built on subjective observations of classic or typical later Acheulean handaxes (Wynn, 1985; Mithen, 1994; Ambrose, 2001). Thus, measuring the degree of symmetry quantitatively, especially at the level of an assemblage, becomes crucial to support these beliefs. Moreover, a proper understanding of the symmetrical nature of handaxes is significant for China, as bilateral and bifacial symmetry of this type is considered to be a basic criterion in defining handaxes (see Gao, 2012 for the latest discussion). 2. Background: the study of handaxe symmetry In order to objectively measure the symmetrical degree of handaxes, Saragusti et al. (1998) proposed a Continuous
66
H. Li et al. / Quaternary International 400 (2016) 65e72
Symmetry Measure (CSM) approach and applied it to the study of three handaxe assemblages from Israel. The results show a generally increased trend in handaxe symmetry from the Early Pleistocene site of Ubeidiya to the Middle Pleistocene sites of Gesher Benot Ya'aqov and Ma'ayan Barukh. Nevertheless, the authors also argued that time is not the only factor affecting the degree of symmetry. Other factors, such as the nature of the raw material, are also important in determining the final shape. In addition, they noticed that even in Ubeidiya nearly symmetrical handaxes did occur, which may indicate that the ability of perceiving symmetry already existed in the earliest phase of the Acheulean (Saragusti et al., 1998). These two views, in our opinion, are instructive for our understanding of the nature of handaxe symmetry and the minds of Acheulean hominids. To further test the change in handaxe symmetry over time, Saragusti et al. (2005) proposed an alternative quantitative method by using the ‘tangent representation’ in mathematics. In addition to the assemblages used earlier, they added two later Acheulean samples from the Tabun cave (bed 90 and Layer E) in Israel. Interestingly, the results show that the symmetry values of the two Tabun samples are actually close to the early Acheulean sample from Ubeidiya (Saragusti et al., 2005). This, in our understanding, indicates that the symmetry of handaxes is not strictly time-related but can have other causes influencing variability. The two methods above were subsequently adopted by other scholars (Machin et al., 2007; Grosman et al., 2011). In addition to these, an Index of Symmetry was also proposed by Hardaker and Dunn (2005), Lycett et al. (2006) and Lycett (2008), although the calculation of this index was based on two different quantitative methods. Among them, the Flip Test proposed by Hardaker and Dunn (2005) is a simple and easily implemented method that uses photography and the calculation of pixels. Using the Flip Test method, Underhill (2007) re-examined one handaxe sample from the later Acheulean site of Cave of Hearths, which was previously subjectively studied using a ‘By-Eye’ measure by McNabb et al. (2004). Interestingly, Underhill's quantitative result confirmed McNabb et al.'s (2004) conclusion that symmetry was not a high priority in the production of handaxes at Cave of Hearths, although absolute symmetry did occasionally occur (Underhill, 2007). More recently, Cole (2011, 2015) systematically analyzed eight handaxe samples from British Lower to Middle Palaeolithic sites, with the ages of these sites spanning from MIS13 to MIS3. The results show that fully symmetrical handaxes in these assemblages from the later Acheulean onwards are actually at a consistently low level. Overall, this brief overview demonstrates two main points: 1) for a better understanding of the nature of handaxe symmetry, we need to conduct more quantitative analyses; and 2) only then can the questions of a ubiquitously imposed final symmetrical shape of handaxes and an increased degree of symmetry over time be assessed. In this paper, we develop a three-dimensional (3D) quantitative approach to measure the degree of symmetry of handaxes from the Danjiangkou Reservoir Region (DRR), central China (Fig. 1). Traditional analyses have actually been twodimensional, i.e., focusing on the lateral contours of a handaxe. However here, with the aid of 3D scanning technology, we can analyze symmetry from a three-dimensional perspective for the first time, i.e., focusing on the volume of a handaxe. In addition, our analysis provides not only information on the bilateral symmetry, as most previous studies have done, but also on the symmetry of the profile view. The meaning of a mental template in handaxe production is also discussed according to the DRR sample.
3. Materials and methods The handaxe samples studied in this paper are from the Danjiangkou Reservoir Region (DRR) in central China (Fig. 1). Detailed technological analyses have shown both variability and commonalities of the DRR handaxes relative to western Acheulean examples, and we have argued that the Large Cutting Tools assemblage in DRR belongs to a true Acheulean techno-complex (Kuman et al., 2014; Li et al., 2014a,b). To reveal any potential temporal trend of change in symmetry, handaxes from the Middle Pleistocene terrace 3 (N ¼ 92; 76 are surface-collected and 16 are in situ) and early Late Pleistocene terrace 2 (N ¼ 25; surface-collected) of the Han and Dan Rivers in DRR are used; we recognize that the sample number from terrace 2 is relatively small (Liu and Feng, 2014; Li et al., 2014b; Pei et al., 2015). Previously the ages of terraces 3 and 2 was mainly based on sedimentological observations and geomorphological context. The higher terrace 3 was considered to belong to the Middle Pleistocene, while the lower terrace 2 was known to be younger and was suggested to be of Late Pleistocene age. Recently, however, numericaldating methods were applied at some of the excavated sites on both terraces. The ESR, OSL and palaeomagnetic dating of the handaxe-bearing sites of Shuangshu and Maling 2A on terrace 3 have confirmed the ages of these two sites as Middle Pleistocene (Li et al., 2014b; Pei et al., 2015). Specifically, the age of Shuangshu is in the first half of Middle Pleistocene (651 ± 65 e 518 ± 52 ka; Li et al., 2014b), while the age of Maling 2A is in the second half of Middle Pleistocene (386 ± 30 e 221 ± 20 ka; Pei et al., 2015). The in situ handaxes excavated from the Shuangshu site are identical to the surface-collected samples on terrace 3 (Li et al., 2014b). For terrace 2, OSL and TT-OSL dating have been successful at the Dishuiyan site and obtained an age of ca 100e50 ka (Liu and Feng, 2014). More than 20 handaxes excavated from the site also confirm the provenance of the 25 surface-collected specimens used in this study. With the use of 3D scanning technology, we attempt here to establish an alternative quantitative method to measure the symmetry of handaxes in both plan and profile views. Two types of 3D laser scanners, NextEngine and Range 7, were first used to capture 3D images of the DRR handaxes. Two steps, cleaning and merging, were carried out in this process. Cleaning aims to remove unwanted areas of a scan such as the platform used to support the tool. The purpose of merging is to build a complete 3D image from multiple scans of different portions of a tool. These images were then imported into Avizo Fire 3D Imaging Software to calculate the volume of a handaxe in its respective segments. A handaxe is segmented into two parts in both its plan and profile views based on the long axis, using the distal end as the guide for alignment. In Fig. 2, we present an example of how to orientate and segment a handaxe. The volume of each portion is then accurately calculated using the same software. The basic principle of our analysis is that the closer the volume value of each segmented portion is (in plan and profile views), the higher the degree of symmetry of the handaxe, and vice versa. Pearson's correlation (r) was first used to estimate the overall degree of symmetry of handaxes in the two views and for the different terraces. In order to show the variable range of symmetry in a complete whole assemblage, we then converted the degree of deviation of a handaxe from complete symmetry into an absolute distance (D) value using the formula
x0 y0 D ¼ pffiffiffi 2
H. Li et al. / Quaternary International 400 (2016) 65e72
67
Fig. 1. Location of the Danjiangkou Reservoir Region (DRR) in central China and the distribution of handaxe-bearing sites in this region.
Fig. 2. The top three images surrounded by a triangle show the method of orientation for a handaxe. The plan view is orientated based on the long axis, using the distal end as the guide. The profile view is orientated on an axis passing through the tip of the handaxe. The bottom images surrounded by two trapezoids show the segmentation of a handaxe into two halves in both the plan and profile views.
where x0 and y0 are the volume values for two parts (the plan and profile views) of the individual specimen, and the order of these two values is interchangeable (see Appendix A for a detailed explanation of this algorithm). In addition, by using these absolute distance values, it becomes possible to explore the factor(s) that influenced the degree of symmetry of the DRR handaxes.
4. Results 4.1. Overall degree of symmetry for DRR handaxes (terraces 3 and 2) Pearson's correlation shows that the two halves of handaxes in plan view are strongly correlated, regardless of their different
68
H. Li et al. / Quaternary International 400 (2016) 65e72
Fig. 3. The correlation between two halves of the DRR handaxes in both plan and profile views.
contexts (terrace 3, r ¼ 0.909, p < 0.001; or terrace 2, r ¼ 0.871, p < 0.001). For the profile views, however, the results show that the two halves of handaxes, both from terrace 3 (r ¼ 0.217, p < 0.05) and terrace 2 (r ¼ 0.129, p ¼ 0.539), are weakly correlated (see Fig. 3). Therefore, there is a clear pattern that the bilateral (plan view) symmetry of the DRR handaxes is significantly higher than the bifacial (profile view) symmetry, and indeed there is probably no symmetry in profile view. In addition,
profile view, the mean distance values of handaxes from terrace 3 and terrace 2 are 59,531.3 and 74,015.2 respectively (Table 1). Thus, we can see that two mean values for each view are consistent with the correlation analyses above. The overall degree of symmetry for plan views shows a much higher statistical significance (p < 0.001) than the profile views (see Table 1 for the results of t-test), and there are no dramatic changes in the symmetry of both views over time.
Table 1 Mean, SD and CV of deviation from absolute symmetry (D) of the DRR handaxes and a t-test for mean values between plan and profile views, and between the terraces.
Terrace 3
Terrace 2
t-statistic df p-value
Mean SD CV Mean SD CV
Plan view
Profile view
t-statistic
df
p-value
15,869.2 15,931.8 100.4 16,363.6 11,767.2 71.9 0.172 51 0.864
59,531.3 57,568.1 96.7 74,015.2 54,539.4 73.7 1.128 115 0.262
7.011
105
<0.001
5.166
26
<0.001
the results demonstrate that no prominent differences are seen in handaxes from both terraces, no matter which view is examined. Thus there are no simple temporal trends in handaxe symmetry for these two samples. 4.2. Absolute values of symmetry of the DRR handaxes and their variability at an assemblage level By using the mathematic formula described above, we calculated the absolute value of symmetry as the deviated distance (D) of a handaxe from perfect symmetry for each specimen. The smaller the absolute value is, the higher the degree of symmetry of the handaxe. The results in Table 1 show that for the plan view, the average distance (D) value for handaxes from terrace 3 is 15,869.2, and 16,363.6 for handaxes from terrace 2. For symmetry in the
The absolute distance values attained here enable us to examine the variability of symmetry in the whole assemblage. The boxplot in Fig. 4 shows that there is extensive variability of symmetry in both views for samples from both terrace 3 and terrace 2, although the absolute values (D) for plan views are generally lower than for the profile views. It is thus unlikely that there is a mental template for the final symmetrical shape of handaxes. Another phenomenon shown in this figure is that, for both plan and profile views, symmetrical values close to 0, i.e., complete symmetry, do occur, although they are few in number (Fig. 4). Therefore, we suggest that the ability to produce completely symmetrical handaxes was possessed by knappers, but the symmetrical shape was not a high priority in the manufacture.
H. Li et al. / Quaternary International 400 (2016) 65e72
4.3. Influence of raw materials, blanks and the types of shaping on symmetry of the DRR handaxes In order to avoid sample bias, here we only analyze the larger handaxe sample (N ¼ 92) from terrace 3 of DRR. The types of raw materials are first examined. Quartz phyllite (N ¼ 67, 72.8%) is the dominant raw material, while other raw materials, including trachyte and igneous rocks, only occupy a relatively small proportion (N ¼ 25, 27.2%). To facilitate statistics, we divide the handaxes into these two groups, namely, quartz phyllite and other raw materials. The boxplot in Fig. 5a shows that for symmetry in plan view, the quartz phyllite handaxes have a generally larger variable range than those made from other raw materials, while in the profile view, the reverse is the case. However, these differences are not statistically significant, as shown in Table 2.
69
different types of shaping did influence the final degree of symmetry of the DRR handaxes in their profile views, although the general degree of symmetry for profile views is much lower than for plan views. 5. Discussion and conclusion The increase in quantitative analyses of symmetry in handaxes has questioned some previous subjective beliefs. In particular, a much debated question is whether there was a stable mental template or a high degree of standardization for the final shape of handaxes with regard to symmetry (Underhill, 2007; McNabb, 2013). The quantitative study in this paper provides new evidence to examine this question for handaxes in DRR, China.
Table 2 Mean, SD and CV of deviation from absolute symmetry (D) of the DRR handaxes made on quartz phyllite and other raw materials and the t-test for mean values between these two groups. Quartz phyllite (N ¼ 67)
Plan view Profile view
Others (N ¼ 25)
Mean
SD
CV
Mean
SD
CV
16,776.8 57,094.0
17,255.1 59,810.0
102.9 104.8
13,436.9 66,063.4
11,625.8 51,647.8
86.5 78.2
Both large flakes (N ¼ 45) and cobbles (N ¼ 45) were used as blanks to make the DRR handaxes. There are two handaxes whose blank is indeterminate. The boxplots in Fig. 5b show that, in the plan view, handaxes made on flake blanks have overall better values for symmetry than the ones made on cobble blanks. This observation is also supported by the statistically significant difference (p < 0.01) between the two groups (Table 3). However, for the profile view, the two groups in Fig. 5b show a similar range in values for symmetry, and the t-test also indicates that there is no significant difference on the statistical level (p ¼ 0.933) between the two groups (Table 3). Therefore, we argue that, at least for plan views, the type of blank did play a role in the degree of symmetry of the DRR handaxes.
t-statistic
df
p-value
1.064 0.663
64 90
0.291 0.509
Our results show first that, regardless of the view, plan view (bilateral) or profile view (bifacial), the DRR handaxes show great variability in the degree of symmetry. Thus, in general, we argue that there was no strictly imposed final symmetrical shape for the DRR handaxes, and the overall high degree of symmetry on plan views is probably a by-product of bilateral shaping. However, the presence of rare near-symmetrical handaxes in the samples from both terraces indicates that the ability to produce perfect symmetrical handaxes existed, but for some reason, it did not occur consistently. In addition, comparisons of handaxes from both terraces demonstrate that the degree of symmetry did not increase over time in these two samples. Finally, both the type of blank and the type of shaping
Table 3 Mean, SD and CV of deviation from absolute symmetry (D) of the DRR handaxes made on flakes and cobbles and the t-test for mean values between these two groups. Flakes (N ¼ 45)
Plan view Profile view
Cobbles (N ¼ 45)
Mean
SD
CV
Mean
SD
CV
11,514.4 59,610.6
12,242.8 66,793.9
106.3 112.1
20,289.5 60,639.8
18,317.0 48,124.5
90.3 79.4
Finally, we examined the possible influence of types of shaping on handaxe symmetry. Three shaping types were used in our analysis, namely, bifacial, partly bifacial and unifacial (see Kuman et al., 2014; Li et al., 2014a). Fig. 5c shows that in the plan view, the three groups show a similar range of values. The KruskalleWallis test also shows that there are no significant differences (p ¼ 0.585) among the three groups (Table 4). For the profile view, however, Fig. 5c shows that there is an apparently increasing trend in the D values (i.e., the degree of symmetry is decreasing) from bifacial to partly bifacial and to unifacial shaping. This is confirmed by the KruskalleWallis test, which shows the differences among the three groups to be at a statistically significant level (p < 0.05; see Table 4). Therefore, we can conclude that
t-statistic
df
p-value
2.672 0.084
77 80
<0.01 0.933
play roles in determining the final degree of symmetry of the DRR handaxes. According to these overall results, we would first agree with McPherron's (2000) opinion that the final shape (in this case, the degree of symmetry) of a handaxe is most likely related to basic factors, rather than a specific mental template that existed in the knappers' minds. In addition, we would argue that although a mental template for a preferred end product is absent, a conceptual standardization did indeed exist. As suggested by McNabb et al. (2004), conceptual standardization is based on the “individualized memic constructs” that were generated by social groups and became rooted in the minds of individuals. Specific to the Acheulean techno-complex, this conceptual standardization
Table 4 Mean of deviation from absolute symmetry (D) of the DRR handaxes made with different types of shaping and the KruskalleWallis test of mean values among the three groups.
Plan view Profile view
Bifacial (N ¼ 37)
Partly bifacial (N ¼ 38)
Unifacial (N ¼ 16)
chi-squared
df
p-value
15,649.1 41,317.3
14,957.2 66,287.2
17,169.5 81,320.4
1.074 6.693
2 2
0.585 <0.05
70
H. Li et al. / Quaternary International 400 (2016) 65e72
Fig. 4. Boxplots of deviation from absolute symmetry (D) for plan and profile views of samples from both terraces.
includes the detaching of large flakes, the creating of a cleaver bit, the general concept of bilateral and/or bifacial flaking for handaxes, etc. This shared conceptual standardization does not have to result in a standardized end product, i.e., physical standardization from the perspective of material culture (McNabb et al., 2004). Because of the substantial variability in the final degree of symmetry of handaxes from both DRR and some western Acheulean sites (McNabb et al., 2004; Underhill, 2007; McNabb, 2013; Cole, 2015), we also agree with McNabb et al. (2004) that the symbolic or signaling implication of handaxe forms did not exist. Some studies focus on classifying the cognitive levels of Acheulean people by using a theoretical model, such as the Social
Brain Hypothesis or the Identity Model (Dunbar, 2003; Hodgson, 2009, 2012, 2015; McNabb, 2012; Cole, 2012, 2015), which is beyond the discussion in this paper. What we emphasize here is that we should make a distinction between two types of mental templates: conceptual standardization and physical standardization. In conclusion, we suggest that quantitative study of symmetry of handaxes is of particular importance, and that we should promote its application to more samples from different regions and different time periods and analyze the degree of symmetry in a comparative context. Only then can we achieve a proper understanding of the nature of handaxe symmetry and the minds and cognitive capacities of Acheulean people.
Fig. 5. Boxplots of deviation from absolute symmetry (D) for both plan and profile views, according to raw materials, blanks and the types of shaping.
H. Li et al. / Quaternary International 400 (2016) 65e72
Acknowledgements This research has been funded by: the Chinese Government Graduate Student Overseas Study Program (grant number [2013] 3009); the Chinese Natural Science Foundation (grant number 40972016); the Cultural Relics Protection Research Project of Hubei Reservoir Area of South-North Water Diversion Foundation (grant number NK02); the ChinaeSouth Africa Bilateral Programme in Palaeosciences, through grants provided by the Ministry of Science and Technology of China to Prof. Liu Wu (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, grant number 2007DFB20330) and by the National Research Foundation of South Africa to Prof. R.J. Clarke (University of the Witwatersrand, grant number 68625). Current funding is provided by grants in the same bilateral programme to Prof. Gao Xing (IVPP) and to K. Kuman (NRF grant number 88480). We thank Profs. Gao Xing and Robin Dennell for their invitation to contribute to this issue.
Appendix A
The degree of symmetry of a handaxe can be represented by an absolute value. This value shows the deviation of a handaxe from complete symmetry. The principle of how to calculate this absolute value is explained by using the following figure: In this figure, the diagonal line (across original point (0)) is expressed by the formula: x y ¼ 0. All points on this line possess an equal value on both the x-axis and y-axis. The volumes for the two halves of a handaxe can be projected to this coordinate as a specific point. For instance, for the point P (x0, y0), x0 and y0 can represent volume values for the two halves of a handaxe. If the volume values for the two halves of a handaxe are equal to each other, this point will locate on the line of x y ¼ 0, e.g., point Q. In this case, this handaxe can be regarded as having perfect symmetry. However, if the volume values are not equal to each other, it will
71
indicate that this handaxe is not in perfect symmetry, and the projected point (e.g., point P in the figure) will deviate from x y ¼ 0 line. The perpendicular distance (D) from this point to the line of x y ¼ 0 thus indicates the degree of deviation of a handaxe from perfect or complete symmetry. The value of D is calculated by the following formula:
x0 y0 D ¼ pffiffiffi : 2 If the D value is closer to 0, the degree of symmetry of a handaxe is higher, and vice versa.
References Ambrose, S.H., 2001. Paleolithic technology and human evolution. Science 291, 1748e1753. Ashton, N.M., McNabb, J., 1994. Bifaces in perspective. In: Ashton, N., David, A. (Eds.), Stories in Stone. Lithic Studies Society, London, pp. 182e191. Cole, J.N., 2011. Hominin Cognitive and Behavioural Complexity in the Pleistocene: Assessment through Identity, Intentionality and Visual Display (Unpublished Ph D thesis). University of Southampton. Cole, J.N., 2012. The identity model: a method to access visual display within the Palaeolithic. Human Origins 1, 24e40. Cole, J.N., 2015. Handaxe symmetry in the Lower and Middle Palaeolithic: implications for the Acheulean gaze. In: Coward, F., Hosfield, R., Pope, M., WenbanSmith, F. (Eds.), Settlement, Society and Cognition in Human Evolution: Landscapes in Mind. Cambridge University Press, Cambridge, pp. 234e257. Davidson, I., Noble, W., 1993. Tools and language in human evolution. In: Gibson, K., Ingold, T. (Eds.), Tools, Language and Cognition in Human Evolution. Cambridge University Press, Cambridge, pp. 363e388. Dunbar, R.I.M., 2003. The social brain: mind, language, and society in evolutionary perspective. Annual Review of Anthropology 32, 163e181. Edwards, S.W., 2001. A modern knapper's assessment of the technical skill of the Late Acheulean biface workers at Kalambo Falls. In: Clark, J.D. (Ed.), Kalambo Falls Prehistoric Site III. Cambridge University Press, Cambridge, pp. 605e611. Gao, X., 2012. Characteristics and significance of paleolithic handaxes from China. Acta Anthropologica Sinica 31 (2), 97e112 (in Chinese with English abstract). Grosman, L., Goldsmith, Y., Smilansky, U., 2011. Morphological analysis of Nahal Zihor handaxes: a chronological perspective. PaleoAnthropology 203e215. Hardaker, T., Dunn, S., 2005. The flip test - a new statistical measure for quantifying symmetry in stone tools. Antiquity 79, 306. Hodgson, D., 2009. Evolution of the visual cortex and the emergence of symmetry in the Acheulean techno-complex. Comptes Rendus Palevol 8, 93e97. Hodgson, D., 2010. Another side of symmetry: the Acheulean biface debate. Antiquity 84, 325. Hodgson, D., 2011. The first appearance of symmetry in the human lineage: where perception meets art. Symmetry 3, 37e53. Hodgson, D., 2012. Hominin tool production, neural integration and the social barin. Human Origins 1, 41e64. Hodgson, D., 2015. The symmetry of Acheulean handaxes and cognitive evolution. Journal of Archaeological Science: Reports 2, 204e208. Jones, P.R., 1979. Effects of raw materials on biface manufacture. Science 204, 835e836. Jones, P.R., 1980. Experimental butchery with modern stone tools and its relevance for Palaeolithic archaeology. World Archaeology 12, 153e165. Jones, P.R., 1994. Results of experimental work in relation to the stone industries of Olduvai Gorge. In: Leakey, M.D., Roe, D. (Eds.), Olduvai Gorge: Excavation in Beds III, IV and the Masek Beds, 1968-1971. Cambridge University Press, Cambridge, pp. 254e298. Kohn, M., Mithen, S., 1999. Bifaces: products of sexual selection? Antiquity 73, 518e526. Kuman, K., Li, C.R., Li, H., 2014. Large cutting tools in the Danjiangkou Reservoir Region, central China. Journal of Human Evolution 76, 129e153. Li, H., Li, C.R., Kuman, K., 2014a. Rethinking the “Acheulean” in East Asia: evidence from the recent investigations in the Danjiangkou Reservoir Region, central China. Quaternary International 347, 163e175. Li, H., Li, C.R., Kuman, K., Chen, J., Yao, H.T., Li, Z., 2014b. The Middle Pleistocene Acheulean site of Shuangshu in the Danjiangkou Reservoir Region, central China. Journal of Archaeological Science 52, 391e409. Liu, Y., Feng, X.B., 2014. Handaxes of 100e50 ka B.P. found in Yunxian County, Hubei. In: Weekly of Chinese Cultural Relics, 3rd of January, 8 (in Chinese with English abstract). Lycett, S.J., von Cramon-Taubadel, N., Foley, R., 2006. A crossbeam co-ordinate calliper for morphometric analysis of lithic nuclei: a description, test and empirical examples of application. Journal of Archeological Science 33, 847e861. Lycett, S.J., 2008. Acheulean variation and selection: Does handaxe symmetry fit neutral expectations? Journal of Archaeological Science 35, 2640e2648.
72
H. Li et al. / Quaternary International 400 (2016) 65e72
Machin, A.J., Hosfield, R.T., Mithen, S.J., 2007. Why are some handaxes symmetrical? Testing the influence of handaxe morphology on butchery effectiveness. Journal of Archaeological Science 34, 883e893. McNabb, J., 2012. The importance of conveying visual information in Acheulean society. The background to the visual display hypothesis. Human Origins 1, 1e23. McNabb, J., 2013. Pole to pole. Archaeology and adaptation in the Middle Pleistocene at opposite ends of the Acheulean world. Oxford Journal of Archaeology 32 (2), 123e146. McNabb, J., Binyon, F., Hazelwood, L., 2004. The large cutting tools from the South African Acheulean and the question of social traditions. Current Anthropology 45, 653e677. McPherron, S.P., 2000. Handaxes as a measure of the mental capabilities of early hominids. Journal of Archaeological Science 27, 655e663. Mitchell, J.C., 1996. Studying biface utilisation at Boxgrove: roe deer butchery with replica handaxes. Lithics 16, 64e69. Mithen, S., 1994. Technology and society during the Middle Pleistocene: hominid group size, social learning and industrial variability. Cambridge Archaeological Journal 4, 3e32. Pei, S.W., Niu, D.W., Guan, Y., Nian, X.M., Yi, M.J., Ma, N., Li, X.L., Sahnouni, M., 2015. Middle Pleistocene hominin occupation in the Danjiangkou Reservoir Region, Central China: studies of formation processes and stone technology of Maling 2A site. Journal of Archaeological Science 53, 391e407. Pelegrin, J., 1993. A framework for analysing prehistoric stone tool manufacture and a tentative application to some early stone industries. In: Berthelet, A., Chavaillon, J. (Eds.), The Use of Tools by Human and Non-Human Primates. Clarendon Press, Oxford, pp. 302e314. Pope, M., Russel, K., Watson, K., 2006. Biface form and structured behaviour in the Acheulean. Lithics 27, 44e57.
Reber, R., 2002. Reasons for the preference for symmetry. Behavioral and Brain Sciences 25, 415e416. Saragusti, I., Karasik, A., Sharon, I., Smilansky, U., 2005. Quantitative analysis of shape attributes based on contours and section profiles in artifact analysis. Journal of Archaeological Science 32, 841e853. Saragusti, I., Sharon, I., Katzenelson, O., Avnir, D., 1998. Quantitative analysis of the symmetry of artefacts: lower Paleolithic handaxes. Journal of Archaeological Sciences 25, 817e825. Shipton, C., Clarkson, C., Pal, J.N., Jones, S.C., Roberts, R.G., Harris, C., Gupta, M.C., Ditchfield, P.W., Petraglia, M.D., 2013. Generativity, hierarchical action and recursion in the technology of the Acheulean to Middle Palaeolithic transition: a perspective from Patpara, the Son Valley, India. Journal of Human Evolution 65, 93e108. Simao, J., 2002. Tools evolve: the artificial selection and evolution of Palaeolithic tools. Behavioral and Brain Sciences 25, 419. Underhill, D., 2007. Subjectivity inherent in by-eye symmetry judgements and the large cutting tools at the Cave of Hearths, Limpopo Province, South Africa. Papers from the Institute of Archaeology 18, 1e12. White, M.J., 1998. On the significance of Acheulean biface variability in Southern Britain. Proceedings of the Prehistoric Society 64, 15e44. Wynn, T., 1985. Piaget, stone tools and the evolution of human intelligence. World Archaeology 17, 32e42. Wynn, T., 1995. Handaxe enigmas. World Archaeology 27, 10e24. Wynn, T., 2000. Symmetry and the evolution of the modular linguistic mind. In: Carruthers, P., Chamberlain, A. (Eds.), Evolution and the Human Mind: Modularity, Language and Meta-Cognition. Cambridge University Press, Cambridge, pp. 113e139. Wynn, T., 2002. Archaeology and cognitive evolution. Behavioral and Brain Sciences 25, 389e438.
Contents lists available at ScienceDirect
Quaternary International journal homepage: www.elsevier.com/locate/quaint
The symmetry of handaxes from the Danjiangkou Reservoir Region (central China): A methodological consideration Hao Li a, *, Kathleen Kuman a, b, Chaorong Li c a
School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg WITS 2050, South Africa Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg WITS 2050, South Africa c Key Laboratory of Vertebrate Evolution and Human Origins & Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xizhimenwai Street, Beijing 100044, China b
a r t i c l e i n f o
a b s t r a c t
Article history: Available online 10 June 2015
In this paper, we present a three-dimensional (3D) quantitative approach to measure the degree of symmetry of handaxes from the Danjiangkou Reservoir Region (DRR), central China. Our analysis provides not only information on the bilateral symmetry, as most previous studies have done, but also on the symmetry of the profile view. The results show that the overall degree of symmetry of handaxes in plan view is much higher than for profile views in the DRR assemblages. However, the range of values for deviation from absolute symmetry for each specimen indicates that both plan and profile views possess great variability in symmetry. Comparisons of handaxes from two terraces (the Middle Pleistocene Terrace 3 and the early Late Pleistocene Terrace 2) demonstrate that the degree of symmetry did not increase over time in these two samples. Both the type of blank and the type of shaping play roles in determining the final degree of symmetry of the DRR handaxes. According to these results, we argue that there is no strictly imposed final symmetrical shape for the DRR handaxes, and the degree of symmetry is most likely related to some basic factors (e.g., bilateral and bifacial shaping and blank types). However, although a mental template for a preferred end product is absent, a conceptual standardization did indeed exist. © 2015 Elsevier Ltd and INQUA. All rights reserved.
Keywords: Danjiangkou Reservoir Region Acheulean Handaxe 3D scanning Symmetry Mental template
1. Introduction Symmetry is a well-known characteristic of Acheulean handaxes, and various interpretations of why there is an imposed symmetrical form have been proposed by researchers. Some consider that basic factors, such as the size and shape of raw materials, the blank form, and the bilateral and/or bifacial flaking strategy, are linked to the symmetry of handaxes (Jones, 1979, 1994; Davidson and Noble, 1993; Ashton and McNabb, 1994; White, 1998; McPherron, 2000), while others think that functional adaptation, especially increased requirements for cutting and chopping in the Acheulean, would be the main reason for symmetry (Jones, 1980; Mitchell, 1996; Simao, 2002; Machin et al., 2007). In addition, some researchers argue that we should go far beyond these analyses and search for reasons in the social or cognitive context, e.g., strong social communication and learning (Mithen, 1994), sexual selection (Kohn and Mithen, 1999), aesthetic or symbolic sense (Pelegrin, 1993; Edwards, 2001; Reber, 2002; Pope et al., 2006; * Corresponding author. E-mail address: [email protected] (H. Li). http://dx.doi.org/10.1016/j.quaint.2015.05.033 1040-6182/© 2015 Elsevier Ltd and INQUA. All rights reserved.
Hodgson, 2010, 2011), and cognitive ability (Wynn, 1995, 2000, 2002; Shipton et al., 2013; Hodgson, 2015). No matter which explanation is preferred, they are all based on a conventional belief that symmetry of handaxes genuinely exists and can be applied not only to individual classic specimens, but also to handaxes in entire assemblages. However, we should bear in mind that this kind of belief is mainly built on subjective observations of classic or typical later Acheulean handaxes (Wynn, 1985; Mithen, 1994; Ambrose, 2001). Thus, measuring the degree of symmetry quantitatively, especially at the level of an assemblage, becomes crucial to support these beliefs. Moreover, a proper understanding of the symmetrical nature of handaxes is significant for China, as bilateral and bifacial symmetry of this type is considered to be a basic criterion in defining handaxes (see Gao, 2012 for the latest discussion). 2. Background: the study of handaxe symmetry In order to objectively measure the symmetrical degree of handaxes, Saragusti et al. (1998) proposed a Continuous
66
H. Li et al. / Quaternary International 400 (2016) 65e72
Symmetry Measure (CSM) approach and applied it to the study of three handaxe assemblages from Israel. The results show a generally increased trend in handaxe symmetry from the Early Pleistocene site of Ubeidiya to the Middle Pleistocene sites of Gesher Benot Ya'aqov and Ma'ayan Barukh. Nevertheless, the authors also argued that time is not the only factor affecting the degree of symmetry. Other factors, such as the nature of the raw material, are also important in determining the final shape. In addition, they noticed that even in Ubeidiya nearly symmetrical handaxes did occur, which may indicate that the ability of perceiving symmetry already existed in the earliest phase of the Acheulean (Saragusti et al., 1998). These two views, in our opinion, are instructive for our understanding of the nature of handaxe symmetry and the minds of Acheulean hominids. To further test the change in handaxe symmetry over time, Saragusti et al. (2005) proposed an alternative quantitative method by using the ‘tangent representation’ in mathematics. In addition to the assemblages used earlier, they added two later Acheulean samples from the Tabun cave (bed 90 and Layer E) in Israel. Interestingly, the results show that the symmetry values of the two Tabun samples are actually close to the early Acheulean sample from Ubeidiya (Saragusti et al., 2005). This, in our understanding, indicates that the symmetry of handaxes is not strictly time-related but can have other causes influencing variability. The two methods above were subsequently adopted by other scholars (Machin et al., 2007; Grosman et al., 2011). In addition to these, an Index of Symmetry was also proposed by Hardaker and Dunn (2005), Lycett et al. (2006) and Lycett (2008), although the calculation of this index was based on two different quantitative methods. Among them, the Flip Test proposed by Hardaker and Dunn (2005) is a simple and easily implemented method that uses photography and the calculation of pixels. Using the Flip Test method, Underhill (2007) re-examined one handaxe sample from the later Acheulean site of Cave of Hearths, which was previously subjectively studied using a ‘By-Eye’ measure by McNabb et al. (2004). Interestingly, Underhill's quantitative result confirmed McNabb et al.'s (2004) conclusion that symmetry was not a high priority in the production of handaxes at Cave of Hearths, although absolute symmetry did occasionally occur (Underhill, 2007). More recently, Cole (2011, 2015) systematically analyzed eight handaxe samples from British Lower to Middle Palaeolithic sites, with the ages of these sites spanning from MIS13 to MIS3. The results show that fully symmetrical handaxes in these assemblages from the later Acheulean onwards are actually at a consistently low level. Overall, this brief overview demonstrates two main points: 1) for a better understanding of the nature of handaxe symmetry, we need to conduct more quantitative analyses; and 2) only then can the questions of a ubiquitously imposed final symmetrical shape of handaxes and an increased degree of symmetry over time be assessed. In this paper, we develop a three-dimensional (3D) quantitative approach to measure the degree of symmetry of handaxes from the Danjiangkou Reservoir Region (DRR), central China (Fig. 1). Traditional analyses have actually been twodimensional, i.e., focusing on the lateral contours of a handaxe. However here, with the aid of 3D scanning technology, we can analyze symmetry from a three-dimensional perspective for the first time, i.e., focusing on the volume of a handaxe. In addition, our analysis provides not only information on the bilateral symmetry, as most previous studies have done, but also on the symmetry of the profile view. The meaning of a mental template in handaxe production is also discussed according to the DRR sample.
3. Materials and methods The handaxe samples studied in this paper are from the Danjiangkou Reservoir Region (DRR) in central China (Fig. 1). Detailed technological analyses have shown both variability and commonalities of the DRR handaxes relative to western Acheulean examples, and we have argued that the Large Cutting Tools assemblage in DRR belongs to a true Acheulean techno-complex (Kuman et al., 2014; Li et al., 2014a,b). To reveal any potential temporal trend of change in symmetry, handaxes from the Middle Pleistocene terrace 3 (N ¼ 92; 76 are surface-collected and 16 are in situ) and early Late Pleistocene terrace 2 (N ¼ 25; surface-collected) of the Han and Dan Rivers in DRR are used; we recognize that the sample number from terrace 2 is relatively small (Liu and Feng, 2014; Li et al., 2014b; Pei et al., 2015). Previously the ages of terraces 3 and 2 was mainly based on sedimentological observations and geomorphological context. The higher terrace 3 was considered to belong to the Middle Pleistocene, while the lower terrace 2 was known to be younger and was suggested to be of Late Pleistocene age. Recently, however, numericaldating methods were applied at some of the excavated sites on both terraces. The ESR, OSL and palaeomagnetic dating of the handaxe-bearing sites of Shuangshu and Maling 2A on terrace 3 have confirmed the ages of these two sites as Middle Pleistocene (Li et al., 2014b; Pei et al., 2015). Specifically, the age of Shuangshu is in the first half of Middle Pleistocene (651 ± 65 e 518 ± 52 ka; Li et al., 2014b), while the age of Maling 2A is in the second half of Middle Pleistocene (386 ± 30 e 221 ± 20 ka; Pei et al., 2015). The in situ handaxes excavated from the Shuangshu site are identical to the surface-collected samples on terrace 3 (Li et al., 2014b). For terrace 2, OSL and TT-OSL dating have been successful at the Dishuiyan site and obtained an age of ca 100e50 ka (Liu and Feng, 2014). More than 20 handaxes excavated from the site also confirm the provenance of the 25 surface-collected specimens used in this study. With the use of 3D scanning technology, we attempt here to establish an alternative quantitative method to measure the symmetry of handaxes in both plan and profile views. Two types of 3D laser scanners, NextEngine and Range 7, were first used to capture 3D images of the DRR handaxes. Two steps, cleaning and merging, were carried out in this process. Cleaning aims to remove unwanted areas of a scan such as the platform used to support the tool. The purpose of merging is to build a complete 3D image from multiple scans of different portions of a tool. These images were then imported into Avizo Fire 3D Imaging Software to calculate the volume of a handaxe in its respective segments. A handaxe is segmented into two parts in both its plan and profile views based on the long axis, using the distal end as the guide for alignment. In Fig. 2, we present an example of how to orientate and segment a handaxe. The volume of each portion is then accurately calculated using the same software. The basic principle of our analysis is that the closer the volume value of each segmented portion is (in plan and profile views), the higher the degree of symmetry of the handaxe, and vice versa. Pearson's correlation (r) was first used to estimate the overall degree of symmetry of handaxes in the two views and for the different terraces. In order to show the variable range of symmetry in a complete whole assemblage, we then converted the degree of deviation of a handaxe from complete symmetry into an absolute distance (D) value using the formula
x0 y0 D ¼ pffiffiffi 2
H. Li et al. / Quaternary International 400 (2016) 65e72
67
Fig. 1. Location of the Danjiangkou Reservoir Region (DRR) in central China and the distribution of handaxe-bearing sites in this region.
Fig. 2. The top three images surrounded by a triangle show the method of orientation for a handaxe. The plan view is orientated based on the long axis, using the distal end as the guide. The profile view is orientated on an axis passing through the tip of the handaxe. The bottom images surrounded by two trapezoids show the segmentation of a handaxe into two halves in both the plan and profile views.
where x0 and y0 are the volume values for two parts (the plan and profile views) of the individual specimen, and the order of these two values is interchangeable (see Appendix A for a detailed explanation of this algorithm). In addition, by using these absolute distance values, it becomes possible to explore the factor(s) that influenced the degree of symmetry of the DRR handaxes.
4. Results 4.1. Overall degree of symmetry for DRR handaxes (terraces 3 and 2) Pearson's correlation shows that the two halves of handaxes in plan view are strongly correlated, regardless of their different
68
H. Li et al. / Quaternary International 400 (2016) 65e72
Fig. 3. The correlation between two halves of the DRR handaxes in both plan and profile views.
contexts (terrace 3, r ¼ 0.909, p < 0.001; or terrace 2, r ¼ 0.871, p < 0.001). For the profile views, however, the results show that the two halves of handaxes, both from terrace 3 (r ¼ 0.217, p < 0.05) and terrace 2 (r ¼ 0.129, p ¼ 0.539), are weakly correlated (see Fig. 3). Therefore, there is a clear pattern that the bilateral (plan view) symmetry of the DRR handaxes is significantly higher than the bifacial (profile view) symmetry, and indeed there is probably no symmetry in profile view. In addition,
profile view, the mean distance values of handaxes from terrace 3 and terrace 2 are 59,531.3 and 74,015.2 respectively (Table 1). Thus, we can see that two mean values for each view are consistent with the correlation analyses above. The overall degree of symmetry for plan views shows a much higher statistical significance (p < 0.001) than the profile views (see Table 1 for the results of t-test), and there are no dramatic changes in the symmetry of both views over time.
Table 1 Mean, SD and CV of deviation from absolute symmetry (D) of the DRR handaxes and a t-test for mean values between plan and profile views, and between the terraces.
Terrace 3
Terrace 2
t-statistic df p-value
Mean SD CV Mean SD CV
Plan view
Profile view
t-statistic
df
p-value
15,869.2 15,931.8 100.4 16,363.6 11,767.2 71.9 0.172 51 0.864
59,531.3 57,568.1 96.7 74,015.2 54,539.4 73.7 1.128 115 0.262
7.011
105
<0.001
5.166
26
<0.001
the results demonstrate that no prominent differences are seen in handaxes from both terraces, no matter which view is examined. Thus there are no simple temporal trends in handaxe symmetry for these two samples. 4.2. Absolute values of symmetry of the DRR handaxes and their variability at an assemblage level By using the mathematic formula described above, we calculated the absolute value of symmetry as the deviated distance (D) of a handaxe from perfect symmetry for each specimen. The smaller the absolute value is, the higher the degree of symmetry of the handaxe. The results in Table 1 show that for the plan view, the average distance (D) value for handaxes from terrace 3 is 15,869.2, and 16,363.6 for handaxes from terrace 2. For symmetry in the
The absolute distance values attained here enable us to examine the variability of symmetry in the whole assemblage. The boxplot in Fig. 4 shows that there is extensive variability of symmetry in both views for samples from both terrace 3 and terrace 2, although the absolute values (D) for plan views are generally lower than for the profile views. It is thus unlikely that there is a mental template for the final symmetrical shape of handaxes. Another phenomenon shown in this figure is that, for both plan and profile views, symmetrical values close to 0, i.e., complete symmetry, do occur, although they are few in number (Fig. 4). Therefore, we suggest that the ability to produce completely symmetrical handaxes was possessed by knappers, but the symmetrical shape was not a high priority in the manufacture.
H. Li et al. / Quaternary International 400 (2016) 65e72
4.3. Influence of raw materials, blanks and the types of shaping on symmetry of the DRR handaxes In order to avoid sample bias, here we only analyze the larger handaxe sample (N ¼ 92) from terrace 3 of DRR. The types of raw materials are first examined. Quartz phyllite (N ¼ 67, 72.8%) is the dominant raw material, while other raw materials, including trachyte and igneous rocks, only occupy a relatively small proportion (N ¼ 25, 27.2%). To facilitate statistics, we divide the handaxes into these two groups, namely, quartz phyllite and other raw materials. The boxplot in Fig. 5a shows that for symmetry in plan view, the quartz phyllite handaxes have a generally larger variable range than those made from other raw materials, while in the profile view, the reverse is the case. However, these differences are not statistically significant, as shown in Table 2.
69
different types of shaping did influence the final degree of symmetry of the DRR handaxes in their profile views, although the general degree of symmetry for profile views is much lower than for plan views. 5. Discussion and conclusion The increase in quantitative analyses of symmetry in handaxes has questioned some previous subjective beliefs. In particular, a much debated question is whether there was a stable mental template or a high degree of standardization for the final shape of handaxes with regard to symmetry (Underhill, 2007; McNabb, 2013). The quantitative study in this paper provides new evidence to examine this question for handaxes in DRR, China.
Table 2 Mean, SD and CV of deviation from absolute symmetry (D) of the DRR handaxes made on quartz phyllite and other raw materials and the t-test for mean values between these two groups. Quartz phyllite (N ¼ 67)
Plan view Profile view
Others (N ¼ 25)
Mean
SD
CV
Mean
SD
CV
16,776.8 57,094.0
17,255.1 59,810.0
102.9 104.8
13,436.9 66,063.4
11,625.8 51,647.8
86.5 78.2
Both large flakes (N ¼ 45) and cobbles (N ¼ 45) were used as blanks to make the DRR handaxes. There are two handaxes whose blank is indeterminate. The boxplots in Fig. 5b show that, in the plan view, handaxes made on flake blanks have overall better values for symmetry than the ones made on cobble blanks. This observation is also supported by the statistically significant difference (p < 0.01) between the two groups (Table 3). However, for the profile view, the two groups in Fig. 5b show a similar range in values for symmetry, and the t-test also indicates that there is no significant difference on the statistical level (p ¼ 0.933) between the two groups (Table 3). Therefore, we argue that, at least for plan views, the type of blank did play a role in the degree of symmetry of the DRR handaxes.
t-statistic
df
p-value
1.064 0.663
64 90
0.291 0.509
Our results show first that, regardless of the view, plan view (bilateral) or profile view (bifacial), the DRR handaxes show great variability in the degree of symmetry. Thus, in general, we argue that there was no strictly imposed final symmetrical shape for the DRR handaxes, and the overall high degree of symmetry on plan views is probably a by-product of bilateral shaping. However, the presence of rare near-symmetrical handaxes in the samples from both terraces indicates that the ability to produce perfect symmetrical handaxes existed, but for some reason, it did not occur consistently. In addition, comparisons of handaxes from both terraces demonstrate that the degree of symmetry did not increase over time in these two samples. Finally, both the type of blank and the type of shaping
Table 3 Mean, SD and CV of deviation from absolute symmetry (D) of the DRR handaxes made on flakes and cobbles and the t-test for mean values between these two groups. Flakes (N ¼ 45)
Plan view Profile view
Cobbles (N ¼ 45)
Mean
SD
CV
Mean
SD
CV
11,514.4 59,610.6
12,242.8 66,793.9
106.3 112.1
20,289.5 60,639.8
18,317.0 48,124.5
90.3 79.4
Finally, we examined the possible influence of types of shaping on handaxe symmetry. Three shaping types were used in our analysis, namely, bifacial, partly bifacial and unifacial (see Kuman et al., 2014; Li et al., 2014a). Fig. 5c shows that in the plan view, the three groups show a similar range of values. The KruskalleWallis test also shows that there are no significant differences (p ¼ 0.585) among the three groups (Table 4). For the profile view, however, Fig. 5c shows that there is an apparently increasing trend in the D values (i.e., the degree of symmetry is decreasing) from bifacial to partly bifacial and to unifacial shaping. This is confirmed by the KruskalleWallis test, which shows the differences among the three groups to be at a statistically significant level (p < 0.05; see Table 4). Therefore, we can conclude that
t-statistic
df
p-value
2.672 0.084
77 80
<0.01 0.933
play roles in determining the final degree of symmetry of the DRR handaxes. According to these overall results, we would first agree with McPherron's (2000) opinion that the final shape (in this case, the degree of symmetry) of a handaxe is most likely related to basic factors, rather than a specific mental template that existed in the knappers' minds. In addition, we would argue that although a mental template for a preferred end product is absent, a conceptual standardization did indeed exist. As suggested by McNabb et al. (2004), conceptual standardization is based on the “individualized memic constructs” that were generated by social groups and became rooted in the minds of individuals. Specific to the Acheulean techno-complex, this conceptual standardization
Table 4 Mean of deviation from absolute symmetry (D) of the DRR handaxes made with different types of shaping and the KruskalleWallis test of mean values among the three groups.
Plan view Profile view
Bifacial (N ¼ 37)
Partly bifacial (N ¼ 38)
Unifacial (N ¼ 16)
chi-squared
df
p-value
15,649.1 41,317.3
14,957.2 66,287.2
17,169.5 81,320.4
1.074 6.693
2 2
0.585 <0.05
70
H. Li et al. / Quaternary International 400 (2016) 65e72
Fig. 4. Boxplots of deviation from absolute symmetry (D) for plan and profile views of samples from both terraces.
includes the detaching of large flakes, the creating of a cleaver bit, the general concept of bilateral and/or bifacial flaking for handaxes, etc. This shared conceptual standardization does not have to result in a standardized end product, i.e., physical standardization from the perspective of material culture (McNabb et al., 2004). Because of the substantial variability in the final degree of symmetry of handaxes from both DRR and some western Acheulean sites (McNabb et al., 2004; Underhill, 2007; McNabb, 2013; Cole, 2015), we also agree with McNabb et al. (2004) that the symbolic or signaling implication of handaxe forms did not exist. Some studies focus on classifying the cognitive levels of Acheulean people by using a theoretical model, such as the Social
Brain Hypothesis or the Identity Model (Dunbar, 2003; Hodgson, 2009, 2012, 2015; McNabb, 2012; Cole, 2012, 2015), which is beyond the discussion in this paper. What we emphasize here is that we should make a distinction between two types of mental templates: conceptual standardization and physical standardization. In conclusion, we suggest that quantitative study of symmetry of handaxes is of particular importance, and that we should promote its application to more samples from different regions and different time periods and analyze the degree of symmetry in a comparative context. Only then can we achieve a proper understanding of the nature of handaxe symmetry and the minds and cognitive capacities of Acheulean people.
Fig. 5. Boxplots of deviation from absolute symmetry (D) for both plan and profile views, according to raw materials, blanks and the types of shaping.
H. Li et al. / Quaternary International 400 (2016) 65e72
Acknowledgements This research has been funded by: the Chinese Government Graduate Student Overseas Study Program (grant number [2013] 3009); the Chinese Natural Science Foundation (grant number 40972016); the Cultural Relics Protection Research Project of Hubei Reservoir Area of South-North Water Diversion Foundation (grant number NK02); the ChinaeSouth Africa Bilateral Programme in Palaeosciences, through grants provided by the Ministry of Science and Technology of China to Prof. Liu Wu (Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, grant number 2007DFB20330) and by the National Research Foundation of South Africa to Prof. R.J. Clarke (University of the Witwatersrand, grant number 68625). Current funding is provided by grants in the same bilateral programme to Prof. Gao Xing (IVPP) and to K. Kuman (NRF grant number 88480). We thank Profs. Gao Xing and Robin Dennell for their invitation to contribute to this issue.
Appendix A
The degree of symmetry of a handaxe can be represented by an absolute value. This value shows the deviation of a handaxe from complete symmetry. The principle of how to calculate this absolute value is explained by using the following figure: In this figure, the diagonal line (across original point (0)) is expressed by the formula: x y ¼ 0. All points on this line possess an equal value on both the x-axis and y-axis. The volumes for the two halves of a handaxe can be projected to this coordinate as a specific point. For instance, for the point P (x0, y0), x0 and y0 can represent volume values for the two halves of a handaxe. If the volume values for the two halves of a handaxe are equal to each other, this point will locate on the line of x y ¼ 0, e.g., point Q. In this case, this handaxe can be regarded as having perfect symmetry. However, if the volume values are not equal to each other, it will
71
indicate that this handaxe is not in perfect symmetry, and the projected point (e.g., point P in the figure) will deviate from x y ¼ 0 line. The perpendicular distance (D) from this point to the line of x y ¼ 0 thus indicates the degree of deviation of a handaxe from perfect or complete symmetry. The value of D is calculated by the following formula:
x0 y0 D ¼ pffiffiffi : 2 If the D value is closer to 0, the degree of symmetry of a handaxe is higher, and vice versa.
References Ambrose, S.H., 2001. Paleolithic technology and human evolution. Science 291, 1748e1753. Ashton, N.M., McNabb, J., 1994. Bifaces in perspective. In: Ashton, N., David, A. (Eds.), Stories in Stone. Lithic Studies Society, London, pp. 182e191. Cole, J.N., 2011. Hominin Cognitive and Behavioural Complexity in the Pleistocene: Assessment through Identity, Intentionality and Visual Display (Unpublished Ph D thesis). University of Southampton. Cole, J.N., 2012. The identity model: a method to access visual display within the Palaeolithic. Human Origins 1, 24e40. Cole, J.N., 2015. Handaxe symmetry in the Lower and Middle Palaeolithic: implications for the Acheulean gaze. In: Coward, F., Hosfield, R., Pope, M., WenbanSmith, F. (Eds.), Settlement, Society and Cognition in Human Evolution: Landscapes in Mind. Cambridge University Press, Cambridge, pp. 234e257. Davidson, I., Noble, W., 1993. Tools and language in human evolution. In: Gibson, K., Ingold, T. (Eds.), Tools, Language and Cognition in Human Evolution. Cambridge University Press, Cambridge, pp. 363e388. Dunbar, R.I.M., 2003. The social brain: mind, language, and society in evolutionary perspective. Annual Review of Anthropology 32, 163e181. Edwards, S.W., 2001. A modern knapper's assessment of the technical skill of the Late Acheulean biface workers at Kalambo Falls. In: Clark, J.D. (Ed.), Kalambo Falls Prehistoric Site III. Cambridge University Press, Cambridge, pp. 605e611. Gao, X., 2012. Characteristics and significance of paleolithic handaxes from China. Acta Anthropologica Sinica 31 (2), 97e112 (in Chinese with English abstract). Grosman, L., Goldsmith, Y., Smilansky, U., 2011. Morphological analysis of Nahal Zihor handaxes: a chronological perspective. PaleoAnthropology 203e215. Hardaker, T., Dunn, S., 2005. The flip test - a new statistical measure for quantifying symmetry in stone tools. Antiquity 79, 306. Hodgson, D., 2009. Evolution of the visual cortex and the emergence of symmetry in the Acheulean techno-complex. Comptes Rendus Palevol 8, 93e97. Hodgson, D., 2010. Another side of symmetry: the Acheulean biface debate. Antiquity 84, 325. Hodgson, D., 2011. The first appearance of symmetry in the human lineage: where perception meets art. Symmetry 3, 37e53. Hodgson, D., 2012. Hominin tool production, neural integration and the social barin. Human Origins 1, 41e64. Hodgson, D., 2015. The symmetry of Acheulean handaxes and cognitive evolution. Journal of Archaeological Science: Reports 2, 204e208. Jones, P.R., 1979. Effects of raw materials on biface manufacture. Science 204, 835e836. Jones, P.R., 1980. Experimental butchery with modern stone tools and its relevance for Palaeolithic archaeology. World Archaeology 12, 153e165. Jones, P.R., 1994. Results of experimental work in relation to the stone industries of Olduvai Gorge. In: Leakey, M.D., Roe, D. (Eds.), Olduvai Gorge: Excavation in Beds III, IV and the Masek Beds, 1968-1971. Cambridge University Press, Cambridge, pp. 254e298. Kohn, M., Mithen, S., 1999. Bifaces: products of sexual selection? Antiquity 73, 518e526. Kuman, K., Li, C.R., Li, H., 2014. Large cutting tools in the Danjiangkou Reservoir Region, central China. Journal of Human Evolution 76, 129e153. Li, H., Li, C.R., Kuman, K., 2014a. Rethinking the “Acheulean” in East Asia: evidence from the recent investigations in the Danjiangkou Reservoir Region, central China. Quaternary International 347, 163e175. Li, H., Li, C.R., Kuman, K., Chen, J., Yao, H.T., Li, Z., 2014b. The Middle Pleistocene Acheulean site of Shuangshu in the Danjiangkou Reservoir Region, central China. Journal of Archaeological Science 52, 391e409. Liu, Y., Feng, X.B., 2014. Handaxes of 100e50 ka B.P. found in Yunxian County, Hubei. In: Weekly of Chinese Cultural Relics, 3rd of January, 8 (in Chinese with English abstract). Lycett, S.J., von Cramon-Taubadel, N., Foley, R., 2006. A crossbeam co-ordinate calliper for morphometric analysis of lithic nuclei: a description, test and empirical examples of application. Journal of Archeological Science 33, 847e861. Lycett, S.J., 2008. Acheulean variation and selection: Does handaxe symmetry fit neutral expectations? Journal of Archaeological Science 35, 2640e2648.
72
H. Li et al. / Quaternary International 400 (2016) 65e72
Machin, A.J., Hosfield, R.T., Mithen, S.J., 2007. Why are some handaxes symmetrical? Testing the influence of handaxe morphology on butchery effectiveness. Journal of Archaeological Science 34, 883e893. McNabb, J., 2012. The importance of conveying visual information in Acheulean society. The background to the visual display hypothesis. Human Origins 1, 1e23. McNabb, J., 2013. Pole to pole. Archaeology and adaptation in the Middle Pleistocene at opposite ends of the Acheulean world. Oxford Journal of Archaeology 32 (2), 123e146. McNabb, J., Binyon, F., Hazelwood, L., 2004. The large cutting tools from the South African Acheulean and the question of social traditions. Current Anthropology 45, 653e677. McPherron, S.P., 2000. Handaxes as a measure of the mental capabilities of early hominids. Journal of Archaeological Science 27, 655e663. Mitchell, J.C., 1996. Studying biface utilisation at Boxgrove: roe deer butchery with replica handaxes. Lithics 16, 64e69. Mithen, S., 1994. Technology and society during the Middle Pleistocene: hominid group size, social learning and industrial variability. Cambridge Archaeological Journal 4, 3e32. Pei, S.W., Niu, D.W., Guan, Y., Nian, X.M., Yi, M.J., Ma, N., Li, X.L., Sahnouni, M., 2015. Middle Pleistocene hominin occupation in the Danjiangkou Reservoir Region, Central China: studies of formation processes and stone technology of Maling 2A site. Journal of Archaeological Science 53, 391e407. Pelegrin, J., 1993. A framework for analysing prehistoric stone tool manufacture and a tentative application to some early stone industries. In: Berthelet, A., Chavaillon, J. (Eds.), The Use of Tools by Human and Non-Human Primates. Clarendon Press, Oxford, pp. 302e314. Pope, M., Russel, K., Watson, K., 2006. Biface form and structured behaviour in the Acheulean. Lithics 27, 44e57.
Reber, R., 2002. Reasons for the preference for symmetry. Behavioral and Brain Sciences 25, 415e416. Saragusti, I., Karasik, A., Sharon, I., Smilansky, U., 2005. Quantitative analysis of shape attributes based on contours and section profiles in artifact analysis. Journal of Archaeological Science 32, 841e853. Saragusti, I., Sharon, I., Katzenelson, O., Avnir, D., 1998. Quantitative analysis of the symmetry of artefacts: lower Paleolithic handaxes. Journal of Archaeological Sciences 25, 817e825. Shipton, C., Clarkson, C., Pal, J.N., Jones, S.C., Roberts, R.G., Harris, C., Gupta, M.C., Ditchfield, P.W., Petraglia, M.D., 2013. Generativity, hierarchical action and recursion in the technology of the Acheulean to Middle Palaeolithic transition: a perspective from Patpara, the Son Valley, India. Journal of Human Evolution 65, 93e108. Simao, J., 2002. Tools evolve: the artificial selection and evolution of Palaeolithic tools. Behavioral and Brain Sciences 25, 419. Underhill, D., 2007. Subjectivity inherent in by-eye symmetry judgements and the large cutting tools at the Cave of Hearths, Limpopo Province, South Africa. Papers from the Institute of Archaeology 18, 1e12. White, M.J., 1998. On the significance of Acheulean biface variability in Southern Britain. Proceedings of the Prehistoric Society 64, 15e44. Wynn, T., 1985. Piaget, stone tools and the evolution of human intelligence. World Archaeology 17, 32e42. Wynn, T., 1995. Handaxe enigmas. World Archaeology 27, 10e24. Wynn, T., 2000. Symmetry and the evolution of the modular linguistic mind. In: Carruthers, P., Chamberlain, A. (Eds.), Evolution and the Human Mind: Modularity, Language and Meta-Cognition. Cambridge University Press, Cambridge, pp. 113e139. Wynn, T., 2002. Archaeology and cognitive evolution. Behavioral and Brain Sciences 25, 389e438.