Language phylogenies are a potentially powerful way to answer questions about how languages and cultures evolve. Recently phylogenetic methods have been applied to answer a range of questions about the evolution of human languages and cultures. This chapter reviews the historical background of these approaches and provides a detailed methodological overview. Three different applications of phylogenetic methods are discussed: how language phylogenies can be used to test population dispersal hypotheses, to investigate processes in language evolution, and to infer patterns in cultural evolution. The chapter closes with a brief discussion of some controversies over the use of these methods before discussing some future prospects.

Despite a burgeoning science of cultural evolution, relatively little work has focused on the population structure of human cultural variation. By contrast, studies in human population genetics use a suite of tools to quantify and analyse spatial and temporal patterns of genetic variation within and between populations. Human genetic diversity can be explained largely as a result of migration and drift giving rise to gradual genetic clines, together with some discontinuities arising from geographical and cultural barriers to gene flow. Here, we adapt theory and methods from population genetics to quantify the influence of geography and ethnolinguistic boundaries on the distribution of 700 variants of a folktale in 31 European ethnolinguis- tic populations. We find that geographical distance and ethnolinguistic affiliation exert significant independent effects on folktale diversity and that variation between populations supports a clustering concordant with European geography. This pattern of geographical clines and clusters paral- lels the pattern of human genetic diversity in Europe, although the effects of geographical distance and ethnolinguistic boundaries are stronger for folk- tales than genes. Our findings highlight the importance of geography and population boundaries in models of human cultural variation and point to key similarities and differences between evolutionary processes operating on human genes and culture

Wilson’s target article illustrates how evolutionary hypotheses are advancing the science of complex cultural systems. We agree. The following extends the conversation to consider the benefits of evolutionary methods. We restrict our review to computational phylogenetic methods as these are being used to test evolutionary hypotheses about religions.

The languages and folkways of ancient peoples hold little relevance for us, except in one respect: the religions of the ancient world remain our religions. Though religions change, core features of the scriptures and rituals of the world’s most popular religious traditions appear to have been conserved with remarkably high fidelity. We suggest how this striking conservation may be explained from an evolutionary model for religious cooperation according to which slow religious change facilitates cooperation among strangers. At the end, we clarify how historians of religion, in collaboration with psychologists and computational biologists, might test and improve models such as ours.

Donohue et al.’s critique of our work on the origins and spread of the Austronesian language family is marred by misunderstandings of our approach. We respond to these by noting that our Bayesian phylogenetic approach: (1) distinguishes between retentions and innovations probabilistically, (2) focuses on basic vocabulary not ‘the lexicon’, (3) eliminates known loanwords, (4) produces results that are congruent with the results of the comparative method and conflict with the scenarios requiring unprecedented amounts of language shift postulated by Donohue et al.

There are two competing hypotheses for the origin of the Indo-European language family. The conventional view places the homeland in the Pontic steppes about 6000 years ago. An alternative hypothesis claims that the languages spread from Anatolia with the expansion of farming 8000 to 9500 years ago. We used Bayesian phylogeographic approaches, together with basic vocabulary data from 103 ancient and contemporary Indo-European languages, to explicitly model the expansion of the family and test these hypotheses. We found decisive support for an Anatolian origin over a steppe origin. Both the inferred timing and root location of the Indo-European language trees fit with an agricultural expansion from Anatolia beginning 8000 to 9500 years ago. These results highlight the critical role that phylogeographic inference can play in resolving debates about human prehistory.

We claim that making sense of the typological diversity of languages demands a historical/evolutionary approach. We are pleased that the target paper (Dunn et al. 2011a) has served to bring discussion of this claim into prominence, and are grateful that leading typologists have taken the time to respond (commentaries denoted by boldface). It is unfortunate though that a number of the commentaries in this special issue show significant misunderstandings of our paper.
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In the following section we try to explain the basic underlying reasoning, turning in the remaining sections to some of these recurrent points of contention. In the final section, we collect some responses to points made in individual commentaries that did not fit neatly into the body of our response.

Simon J. Greenhill and Russell D. Gray.

The shape and the fabric of human cultural history is the focus of two long-standing debates in linguistics and anthropology. The first concerns the extent to which human history is tree-like (its shape), and the second concerns the unity of that history (its fabric). Proponents of cultural phylogenetics are often accused of assuming that human history has been both highly tree-like and consisting of tightly linked lineages. Critics have pointed out obvious exceptions to these assumptions. Instead of a priori dichotomous disputes about the validity of cultural phylogenetics, we suggest that the debate is better conceptualized as involving positions along continuous dimensions. The challenge for empirical research is, therefore, to determine where particular aspects of culture lie on these dimensions. We discuss the ability of current computational methods derived from evolutionary biology to address these questions. These methods are then used to compare the extent to which lexical evolution is tree-like in different parts of the world and to evaluate the coherence of cultural and linguistic lineages.

The Polynesian lexicon project, POLLEX, was initiated in 1965 by Bruce Biggs in order to provide a large-scale comparative dictionary of Polynesian languages. Since then, POLLEX has grown to include over 55,000 reflexes of more than 4,700 reconstructed forms in 68 languages. These data have enabled many fundamental advances in Polynesian linguistics and prehistory. At almost half a century old, POLLEX is one of the longest-standing databases of linguistic information, and has moved through various incarnations, from type- writer and edge-punched cards, through microfiche to mainframe computer. In the last few years, online databases of linguistic information have become increasingly more prevalent, representing a major shift in the way linguistics is conducted. Online databases provide many advantages over the older forms of data distribution, including high availability, more robust data storage, and easy data manipulation and searching, and they also facilitate the replication of previous studies. This paper announces the latest reincarnation of the POLLEX database as an online resource, POLLEX-Online (http://pollex.org.nz), and describes the technical implementation details.