A COMPARATIVE PHYLOGENETIC APPROACH TO AUSTRONESIAN CULTURAL EVOLUTION Thesis submitted for the degree of Doctor of Philosophy to Department of Anthropology University College London Fiona Marie Jordan 2007 1 ABSTRACT Phylogenetic comparative methods were used to test hypotheses about cultural evolution in ethnolinguistic groups from the Austronesian language family of the Pacific. The case for quantitative statistical approaches to the empirical evolution of linguistic and cultural features was presented. Phylogenetic trees of 67 Austronesian languages were constructed using maximum parsimony and Bayesian Markov Chain Monte Carlo likelihood algorithms on a database of lexical items. The predominant transmission mode of 76 cultural traits was examined at the macroevolutionary level with (i) partial Mantel matrix tests and (ii) multiple regression on phylogenetic and geographic nearest neighbours. Mantel tests showed that both geographic and phylogenetic transmission was correlated with cultural diversity. Geographic distance had a greater overall partial correlation with cultural distance than did phylogenetic distance, but only phylogenetic correlations were found with kinship/social traits. Multiple regression on individual traits found that phylogenetic nearest neighbours predicted more cultural traits, especially those involving the inheritance of resources. Ancestral states of kinship traits were reconstructed using a Bayesian comparative method on a sample of 1000 phylogenies. The root of the tree was reconstructed as having matrilocal post-marital residence and a bilateral, flexible descent system. Proto Oceanic was reconstructed as unilocal and unilineal, and an hypothesis of matriliny and matrilocality could not be rejected. Murdock’s main-sequence theory of the co-evolution of post-marital residence and descent systems was tested. The most likely model of the evolutionary pathway demonstrated that residence changed before descent. Rates of change in residence and descent traits were estimated. A co-evolutionary hypothesis of matriliny and male absence was tested. Contrary to anthropological theory, a high 2 dependence on fishing showed no clear pattern of co-evolution with matrilineal social organisation. Population size of the language community was hypothesized to be a factor influencing lexical change. Conventional statistics showed a significant strong inverse correlation, indicating a relationship between small populations and accelerated lexical change. This correlation disappeared when comparative methods were used to control for phylogeny. Population size appeared to be evolving according to a drift model, while lexical change did not fit a neutral model of evolution. 3 TABLE OF CONTENTS Page Abstract 2 Table of Contents 4 List of Tables 14 List of Figures 16 List of Abbreviations 19 Acknowledgements 20 Frontpiece 21 Chapter 1. The phylogenetic approach to cultural evolution 22 1.1 Summary 22 1.2 Culture and evolution: History and current approaches 23 1.2.1 History 23 1.2.1.1 Cultural ecology 24 1.2.1.2 Sociobiology 24 1.2.2 Current approaches 25 1.2.2.1 Evolutionary psychology 25 1.2.2.2 Human behavioural ecology 25 1.2.2.3 Dual-inheritance theories 26 1.2.2.4 Population history 27 1.2.3 Cultural phylogenetics 28 1.3 Culture has Darwinian properties 29 1.3.1 Similarities between biological and cultural evolution 31 1.3.1.1 Language evolution 31 1.3.2 Differences between biological and cultural evolution 34 1.3.2.1 Many cultural parents 34 1.3.2.2 Cultural evolution can be rapid 35 1.3.2.3 Multiple lineages and multiple phenotypes 35 1.3.3 Units of culture 36 1.3.3.1 Core and periphery 36 1.3.3.2 Culture as species 37 1.3.3.3 Horizontal transmission 38 4 Page 1.4 The phylogenetic approach to cultural evolution 39 1.4.1 Summary 39 1.4.2 Cross-cultural comparison and Galton’s Problem 39 1.4.3 Methods to address Galton’s Problem 43 1.4.3.1 Sampling methods 43 1.4.3.2 Controlled comparison 44 1.4.3.3 Autocorrelation 44 1.4.3.4 Phylogenetically controlled comparison 44 1.4.4 Language phylogenies 45 1.4.5 Material culture phylogenies 47 1.4.6 Comparative tests of cultural hypotheses 48 1.4.6.1 Matriliny and cattle in the Bantu 49 1.4.6.2 Worldwide sex ratio and marriage costs 50 1.4.6.3 Marriage transfers in Indo-European societies 51 1.4.7 Objections to phylogenetic and comparative methods 51 1.4.8 Simulations 54 1.4.9 Different lines of evidence 56 1.5 The ethnographic context: Austronesian cultures of the Pacific 57 1.5.1 Summary 57 1.5.2 Pacific colonisation 58 1.5.3 Austronesian languages 62 1.5.3.1 Austronesian subgrouping 62 1.5.4 The Austronesian dispersal 64 1.5.5 Models of colonisation 66 1.5.5.1 Express train / Out of Asia 66 1.5.5.2 Entangled bank 66 1.5.6 Molecular anthropology in the Pacific 67 1.5.6.1 Mitochondrial DNA 67 1.5.6.2 Y-chromosome lineages 68 1.5.6.3 Autosomal markers 68 1.5.6.4 Sex-specific patterns of dispersal 69 1.5.7 An integrated model 70 1.5.8 Later developments in Austronesian history 70 1.6 Cultural evolution in the Pacific 71 5 Page 1.6.1 Islands as laboratories 71 1.6.2 Evolutionary approaches 72 1.7 Austronesian kinship 74 1.7.1 Descent 74 1.7.2 Residence 75 1.7.2.1 Parental investment 75 1.7.3 Previous work 75 1.8 Structure of the thesis 76 Chapter 2. Phylogenetic methods & Austronesian language trees 80 2.1 Summary 80 2.2 Introduction 81 2.2.1 Phylogenetic methods 81 2.2.2 Phylogenetic trees of human populations 81 2.2.3 Language phylogenies 82 2.2.4 Historical linguistics 83 2.2.5 Computational methods for language phylogenies 84 2.2.6 Survey of studies 85 2.2.7 Algorithms for inferring evolutionary trees 87 2.2.8 Non-tree methods 89 2.3 Bayesian methods 89 2.3.1 Bayesian inference of phylogeny 89 2.3.2 Markov chain Monte Carlo 91 2.3.3 Support for nodes: Posterior probability distributions 91 2.4 Phylogenetic trees of Austronesian languages 92 2.4.1 Aims 92 2.4.2 Austronesian Comparative Dictionary 92 2.4.3 Austronesian Basic Vocabulary Database 93 2.4.4 Data used in this thesis 95 2.5 Tree searches using parsimony 95 2.5.1 Tree searches using parsimony: The 80 language data set 95 2.5.1.1 Bootstrap analysis 96 2.5.2 Results 96 2.5.3 Tree topology 98 6 Page 2.6 Tree searches using Bayesian methods 99 2.6.1 Bayesian estimation of phylogeny 99 2.6.2 Analyses 100 2.6.2.1 Initial Bayesian analyses 100 2.6.2.2 Models of word evolution and the choice of priors 100 2.6.2.3 Outgroup rooting 101 2.6.3 Results 102 2.6.3.1 MCMC sample 102 2.6.3.2 Autocorrelation 102 2.6.4 Bayesian phylogeny 105 2.6.5 Topology 109 2.6.6 Comparison with other results 111 2.7 Conclusions 112 Chapter 3. The comparative method in anthropology 113 3.1 Summary 113 3.2 Introduction 114 3.2.1 The comparative method 114 3.3 Parsimony-based 115 3.3.1 Characteristics of parsimony-based comparative methods 115 3.3.1.1 Shortcomings of parsimony 116 3.4 Likelihood comparative methods 118 3.4.1 Characteristics of likelihood-based comparative methods 118 3.4.1.1 Pagel’s method 118 3.4.2 Bayesian comparative methods 120 3.4.2.1 BayesMultiState 121 3.4.3 Model testing using reversible-jump MCMC 122 3.4.3.1 Reverse-jump MCMC 123 3.4.3.2 Bayes factor 123 3.5 Conclusions 124 7 Chapter 4. Do cultures resemble their neighbours or their cousins? A test of phylogenetic and geographic distance 125 4.1 Summary 125 4.2 Introduction 126 4.2.1 Cultural transmission between groups 126 4.2.2 Macroevolutionary studies of between-group cultural transmissions 127 4.2.3 Adaption and ecology 130 4.2.4 Cultural transmission in Austronesian societies 131 4.2.4.1 Replication 131 4.2.4.2 Alternative approaches 132 4.3 Mantel tests of cultural, geographic, and linguistic distances 133 4.3.1 Aim 133 4.3.2 Distance matrices for tests of diversity 133 4.3.3 Hypotheses 134 4.3.4 Data 135 4.3.4.1 Cultural data 135 4.3.4.2 Language data 135 4.3.4.3 Geographic data 136 4.3.5 Mantel matrix tests 138 4.3.5.1 Program 139 4.3.6 Distance matrices 139 4.3.6.1 Cultural distances 139 4.3.6.2 Linguistic distances 139 4.3.6.3 Geographic distances 140 4.3.6.4 Population size 140 4.3.7 Matrix correlations 141 4.3.7.1 Geographic distance 141 4.3.7.2 Population size 141 4.3.7.3 Cultural distance 141 4.3.7.4 Language and geography 143 4.3.8 Mantel tests: Discussion 143 4.3.8.1 Alternative models 144 4.4 Nearest neighbour analysis 145 4.4.1 Aim 145 4.4.2 Phylogenetic and geographic nearest neighbours 145 8 Page 4.4.3 Estimating nearest neighbours 145 4.4.4 Logistic regression analysis 147 4.4.5 Results of nearest neighbour tests 148 4.4.6 Nearest neighbour tests: Discussion 154 4.5 Cultural transmission: Discussion 155 4.5.1 Comparison with previous work 155 4.5.2 Consideration of the methodologies 157 4.5.3 Conclusion 158 Chapter 5.