Cultural Transmission of Lithic Artefact Traditions: an Experimental Approach Stuart Page Thesis submitted for the degree of Doctor of Philosophy Institute of Archaeology University College London 1 I, Stuart Page confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Stuart Page June 2014 2 Abstract Experimental methods for exploring the idea that cultural variation can be explained as part of a process analogous to that of biological evolution have been used in psychology to examine how human copying error effects the transmission of simple artefact form. Applying these methods in an archaeological framework, this study is the first of its kind to develop a programme of transmission chain experiments exploring different aspects of skill, social interaction and copying error and their effect on the evolution of artefact form in two different Palaeolithic technologies: blade production and Acheulean handaxe manufacture. In the blade replication experiment, form trajectories produced by two different levels of skill could be distinguished, with the more skilled knappers choosing to pass on the best match for blade length, in preference to shape or ridge pattern. In the Acheulean experiments, in conditions where loss of refinement features was expected, a surprising result was the consistent survival of planform symmetry. Where maintaining refinement was the focus of the teaching condition, thinning was achieved to a high level, without loss of size, but paradoxically, symmetry survived less well. It was concluded that the level of knapping skill, in all transmission scenarios, was a key factor in the formation of attribute variation. Difficulty experienced when aligning results from experimentally produced transmission biases with archaeological assemblages, demonstrated that in reality, cultural transmission was likely a fluid process where differing biases occurred at different times within the lifecycle of each Palaeolithic group. The specific signal provided by archaeological assemblages is likely to reflect the skill level and position of the knappers within that cycle, rather than the existence of a singular type of transmission bias. This approach provides new and enhanced ideas on the nature of cultural transmission in the Middle Pleistocene groups of Homo heidelbergensis, reinforcing the importance of teaching in the culture evolutionary process. 3 Contents Abstract 3 Contents 4 List of Illustrations 9 List of Tables 18 Acknowledgements 22 Chapter 1 Introduction 23 1.1 Background to the research problem and original contribution of proposed research 23 1.2 Research aims and experimental design 25 1.3 Thesis structure and focus of transmission chain experiments 30 Chapter 2 Theoretical development of experimental work in lithic archaeology related to knapping and reproduction of artefact form and transmission chain theory 34 2.1.2 Introduction 34 2.1.2 The bio-mechanics of flake removal 35 2.1.3 Lithic variation as a function of skill 39 2.1.4 Cognition and experimental knapping 44 2.1.5 Context and structure of skill acquisition 47 2.1.6 Châine opératoire, social control and methods of instruction 50 2.1.7 Methodological lessons 56 2.2.1 Theoretical background of cultural transmission experiments 60 2.2.2 Stylistic variation or cultural drift 61 2.2.3 Skill acquisition and socially transmitted cultural evolution 65 2.2.4 Complexity of skill-set 70 2.2.5 Measurement of variation 72 2.2.6 The missing link and future research direction 73 2.2.7 Conclusion 76 Chapter 3 Materials and methods 77 3.1 Introduction 77 3.2 Core construction methodology 79 3.2.1 Experiment 1: creating the mould 79 3.2.2 Core production: the porcelain selection process 80 3.2.3 Core production: the core moulding process 82 3.2.4 Core production: the firing process 83 3.2.5 Experiments 2 – 4: mould making procedure 84 3.2.6 Experiments 2 – 4: preform core making procedure 85 4 3.2.7 Drying and firing procedure 86 3.3 Cohort training by lithic technology 87 3.4 Skill assessments and transmission chain allocation 88 3.4.1 Blade production: Experiment 1 89 3.4.2 Acheulean handaxe production: Experiments 2 – 4 90 3.5 Measurement of lithic output 93 3.5.1 Experiment 1: basic blade metrics and discrete morphology 93 3.5.2 Analytical procedure for metric data: coefficient of variation 94 3.5.3 Analytical procedure for combining metric and non-metric approaches 95 3.5.4 Procedure for measuring 3D Euclidean distance and taper 95 3.5.5 Experiments 2 – 4: standard handaxe measurement 96 3.5.6 Extended use of Roe (1968) metrics 100 3.5.7 Refinement: using ImageJ to produce area based measures 101 3.5.8 ImageJ methodology for area based measures 103 3.5.9 Shape: Symmetry and use of Flip Test 113 3.5.10 Identification of trends in differing TCPs 115 3.6 Conclusion 118 Chapter 4 Exploring variation in lithic form in transmission chains Experiment 1: the effects of skill level and perceptual biases on copying blade forms 120 4.1 Introduction 120 4.2 Objectives 121 4.2.1 Target form 122 4.3 Methodology 123 4.3.1 Transmission chain protocol 123 4.3.2 Statistical methodology and analysis 124 4.3.3 Analytical procedure for non-metric data: co-occurrence 127 4.4 Results 128 4.4.1 Metric attribute variability by TC and assemblage 128 4.4.2 Non-metric attribute variability by TC and assemblage 136 4.4.3 Metric variability of target forms by TC 141 4.4.4 Non-metric variability of target forms by TC 143 4.4.5 Co-occurrence: achievement of metric & non-metric attributes by transmission chain 145 4.4.6 Co-occurrence: results from comparing measures of 3D metric shape with degree of taper 146 4.5 Conclusions and effectiveness of Experiment 1 149 Chapter 5 Accounting for and quantifying Acheulean variation 152 5.1 Introduction 152 5.2 Accounting for existing ideas on Acheulean variation 154 5.3 Variation and raw material 158 5.4 Variation and reduction 160 5.5 Demographic theories accounting for Acheulean variation 162 5 5.6 Stasis and random variation: is the Acheulean a genuine cultural tradition? 166 5.7 Discussion and structure of Acheulean transmission chain experiments 170 Chapter 6 Experiment 2: the effects of copying error from uninstructed end-state copying of ovate and pointed handaxes in transmission chains 174 6.1 Introduction 174 6.2 Objectives 176 6.2.1 Target form 177 6.3 Methodology: transmission chain protocol 178 6.4 Results drawn from Roe metrics 181 6.4.1 Basic dimensional measures 181 6.4.2 Refinement ratios 183 6.4.3 Shape measures 186 6.5 Discussion 192 6.6 Conclusion on Roe’s measurement system 195 6.7 Developing new metrics to improve Roe’s measurement system 196 6.8 Metric summary 199 6.9 Using planform and cross-sectional edge area (cm²) Measures as an improvement to Roe’s system of metrics 201 6.9.1 Handaxe refinement measures 201 6.9.2 Handaxe shape measures 204 6.9.3 Conclusion 208 6.10 Handaxe symmetry 209 6.11 Conclusion 214 Chapter 7 Experiment 3: the effects of one-to-one knapping instruction from a cultural parent, on copying pointed handaxes in a transmission chain 216 7.1 Introduction 216 7.2 Objectives 217 7.2.1 Target form 218 7.3 Methodology 218 7.3.1 Transmission chain protocol 218 7.3.2 Measurement 220 7.4 Results from Roe metrics 220 7.4.1 Basic dimensional measures 220 7.4.2 Refinement measures 221 7.4.3 Shape measures 223 7.5 Measures of taper and 3D Euclidean distance 227 7.6 Area based refinement and shape measures from ImageJ 231 7.6.1 Edge and planform area 231 7.6.2 Residual cortex area 233 6 7.6.3 Handaxe shape measures 234 7.7 Symmetry 237 7.8 Conclusion 240 Chapter 8 Experiment 4: the effects of many-to-one transmission from an accomplished peer group, on copying pointed handaxes in a transmission chain 242 8.1 Introduction 242 8.1.2 Objectives 243 8.2 Methodology 243 8.2.1 Transmission chain protocol and target from 243 8.2.2 Measurement 244 8.3 Results from Roe metrics 245 8.3.1 Basic dimensional measures 245 8.3.2 Refinement ratios 246 8.3.3 Shape ratios 250 8.4 Measures of taper and 3D Euclidean distance 255 8.5 Area based refinement and shape measures from ImageJ 259 8.5.1 Edge and planform area 259 8.5.2 Residual cortex area 264 8.5.3 Combining handaxe shape measures 265 8.6 Handaxe symmetry 266 8.7 Conclusion 271 Chapter 9 A comparative study and discussion of transmission biases and their effect on Acheulean handaxe form 273 9.1 Introduction 273 9.2 Basic dimensional measures 275 9.3 Roe refinement ratios 277 9.4 Roe shape 279 9.5 New geometric measures 282 9.6 Area based measures and combined ratio analysis 286 9.7 Handaxe symmetry 289 9.8 Discussion 291 9.8.1 Comparing experimental results with the archaeological record 299 Chapter 10 Conclusion 313 10.1 Summary 313 10.1.2 Main findings 315 10.1.3 Experimental overview 318 10.2 Overcoming methodological issues 321 10.3 Limitations of the research design 324 10.4 Future directions of research into cultural transmission 326 7 Bibliography 331 Appendix 1 Comparison of significance levels derived from R² and the Mann-Kendall tau test. 349 Appendix 2 Co-occurrence matrix of non-metric attributes by knapper and transmission chain 350 Appendix 3 Photographs of Experiment 1 chosen form blades, by transmission chain 352 Appendix 4 Photographs of Experiment 2 chosen form ovate handaxes (TC1) and chosen form pointed handaxes (TC2) 354 Appendix 5 Photographs of Experiment 3 chosen form pointed handaxes 362 Appendix 6 Experiment 4 inter-generational variation