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Context-based cultural transmission biases such as prestige are thought to have been a primary driver in shaping the dynamics of human cultural evolution. However, few empirical studies have measured the importance of prestige relative to other effects, such as the content biases present within transmitted information. Here, we report the findings of an experimental transmission study designed to compare the simultaneous effects of a high- or low-prestige model with the presence of content containing social, survival, emotional, moral, rational, or counterintuitive information. Results from multimodel inference reveal that prestige is a significant factor in determining salience and recall, but that several content biases, specifically social, survival, negative emotional, and biological counterintuitive information, are significantly more influential. Further, we find evidence that prestige serves as a conditional learning strategy when no content cues are available. Our results demonstrate that content biases serve a vital and underappreciated role in cultural transmission Introduction Methods - Experimental protocol - Participants - Story production - Recordings - Data coding and transcription - Data analysis - Ethics statement Results - Sample demographics - Participants showed preferential recall of biased information - Content biases were more influential than prestige bias - Transmission biases explain little variance in recall Discussion - Prestige bias has a minor effect on transmission - Prestige is unconsciously employed as a secondary bias - Content biases have distinct effects - Narrative structural features may aid transmission - Implications for the understanding of transmission

Social inequality is ubiquitous in contemporary human societies, and has deleterious social and ecological impacts. However, the factors that shape the emergence and maintenance of inequality remain widely debated. Here we conduct a global analysis of pathways to inequality by comparing 408 non-industrial societies in the anthropological record (described largely between 1860 and 1960) that vary in degree of inequality. We apply structural equation modelling to open-access environmental and ethnographic data and explore two alternative models varying in the links among factors proposed by prior literature, including environmental conditions, resource intensification, wealth transmission, population size and a well-documented form of inequality: social class hierarchies. We found support for a model in which the probability of social class hierarchies is associated directly with increases in population size, the propensity to use intensive agriculture and domesticated large mammals, unigeniture inheritance of real property and hereditary political succession. We suggest that influence of environmental variables on inequality is mediated by measures of resource intensification, which, in turn, may influence inequality directly or indirectly via effects on wealth transmission variables. Overall, we conclude that in our analysis a complex network of effects are associated with social class hierarchies.

Resumo Este estudo explora o sistema de terminologia de parentesco da língua Proto-Tupí-Guaraní (PTG) a partir de uma perspectiva interdisciplinar, que soma contribuições da Etnologia, da Linguística Histórica e dos trabalhos etnográficos realizados com povos Tupí-Guaraní. Fazem-se inferências sobre pré-história cultural utilizando métodos filogenéticos comparativos, um conjunto de ferramentas computacionais para explorar mudanças evolutivas em populações relacionadas, aplicados a um banco de dados de termos de parentesco em 24 línguas Tupí-Guaraní. Discute-se a amostra usada no estudo, os procedimentos de codificação adotados para dados tipológicos e os componentes, valores iniciais e premissas do modelo evolutivo. A análise de reconstrução de estados ancestrais baseada no critério de máxima parcimônia reconstrói vários traços tipológicos do sistema de parentesco do PTG, como: fusão e bifurcação na primeira geração ascendente (+1); distinções na terminologia de irmãos baseadas na idade relativa e no sexo do ego; e equação terminológica entre irmãos e primos paralelos. O estudo avalia o estado atual da reconstrução de formas linguísticas para termos de parentesco em PTG e mapeia estas formas no sistema inferido por análise comparativa. Este estudo de comprovação de conceito demonstra a utilidade de análise filogenética para inferir estruturas de sistemas de parentesco em comunidades linguísticas ancestrais. Abstract This study explores the kinship terminology of Proto-Tupí-Guaraní (PTG) through an interdisciplinary perspective that draws on ethnology, historical linguistics, and the ethnography of Tupi-Guaranian peoples. Inferences about cultural prehistory are made through phylogenetic comparative methods, a suite of computational tools for exploring evolutionary change in related populations, applied to a dataset of kinship terms from 24 Tupi-Guaranian languages. The study outlines the coding procedure for typological data, along with the parameters, inputs, and assumptions of the evolutionary models. Parsimony-based ancestral state inference is used to reconstruct a number of typological features of the kinship system of PTG, such as fusion and bifurcation in the first ascending generation (+1), relative age and sex-based distinctions in sibling terminology, and terminological equation between siblings and parallel cousins. The current state of reconstruction of the linguistic forms for kinship terms in PTG is reviewed, and these forms are mapped onto the system inferred through comparative analysis. This proof-of-concept study demonstrates the utility of phylogenetic analysis for inferring kinship structures in ancestral language communities.

This special issue “Evolutionary Approaches to Cross-Cultural Anthropology” brings together scholars from the fields of behavioral ecology, evolutionary psychology, and cultural evolution whose cross-cultural work draws on evolutionary theory and methods. The papers here are a subset of those presented at a symposium we organized for the 2011 meeting of the Society for Cross-Cultural Research held in Charleston, South Carolina. Collectively, our authors show how an engagement with cultural variation has enriched evolutionary anthropology, and these papers showcase how cross-cultural research can benefit from the theoretical and methodological contributions of an evolutionary approach.

Social structure in human societies is underpinned by the variable expression of ideas about relatedness between different types of kin. We express these ideas through language in our kin terminology: to delineate who is kin and who is not, and to attach meanings to the types of kin labels associated with different individuals. Cross-culturally, there is a regular and restricted range of patterned variation in kin terminologies, and to date, our understanding of this diversity has been hampered by inadequate techniques for dealing with the hierarchical relatedness of languages (Galton's Prob- lem). Here I use maximum-likelihood and Bayesian phylogenetic compara- tive methods to begin to tease apart the processes underlying the evolution of kin terminologies in the Austronesian language family, focusing on terms for siblings. I infer (1) the probable ancestral states and (2) evolutionary models of change for the semantic distinctions of relative age (older/younger sibling) and relative sex (same-sex/opposite-sex). Analyses show that early Austronesian languages contained the relative-age, but not the relative-sex distinction; the latter was reconstructed firmly only for the ancestor of Eastern Malayo-Polynesian languages. Both distinctions were best charac- terized by evolutionary models where the gains and losses of the semantic distinctions were equally likely. A multi-state model of change examined how the relative-sex distinction could be elaborated and found that some transitions in kin terms were not possible: jumps from absence to heavily elaborated were very unlikely, as was piece-wise dismantling of elaborate distinctions. Cultural ideas about what types of kin distinctions are important can be embedded in the semantics of language; using a phylogenetic evolutionary framework we can understand how those distinctions in meaning change through time. Social structure in human societies is underpinned by the variable expression of ideas about relatedness between kin. Notions of marriageability, determination of group membership, rules of residence and reciprocal obligations, and theories of child-rearing influence much of how human communities have structured their interactions. Anthropologists have long noted that while on the surface there is 1 Evolutionary Processes in Language and Culture, Max Planck Institute for Psycholinguistics, PB 310

Very little research has attempted to describe normal human variation in female genitalia, and no studies have compared the visual images that women might use in constructing their ideas of average and acceptable genital morphology to see if there are any systematic differences. The objective of the present work was to determine if visual depictions of the vulva differed according to their source so as to alert medical professionals and their patients to how these depictions might capture variation and thus influence perceptions of 'normality'. A comparative analysis was conducted by measuring (a) published visual materials from human anatomy textbooks in a university library, (b) feminist publications (print and online) depicting vulval morphology and (c) online pornography, focusing on the most visited and freely accessible sites in the UK. Post hoc tests showed that labial protuberance was significantly less (p0.001, equivalent to approximately 7emsp14;mm) in images from online pornography compared to feminist publications. All five measures taken of vulval features were significantly correlated (p0.001) in the online pornography sample, indicating a less varied range of differences in organ proportions than the other sources where not all measures were correlated. Women and health professionals should be aware that specific sources of imagery may depict different types of genital morphology and may not accurately reflect true variation in the population, and consultations for genital surgeries should include discussion about the actual and perceived range of variation in female genital morphology.

Kanazawa (2007) proposes the ‘evolutionary psychological imagination’ (p.7) as an authoritative framework for understanding complex social and public issues. As a case study of this approach, Kanazawa addresses acts of international terrorism, specifically suicide bombings committed by Muslim men. It is proposed that a comprehensive explanation of such acts can be gained from taking an evolutionary perspective armed with only three points of cultural knowledge: 1. Muslims are exceptionally polygynous, 2. Muslim men believe they will gain reproductive access to 72 virgins if they die as a martyr and 3. Muslim men have limited access to pornography, which might otherwise relieve the tension built up from intra-sexual competition. We agree with Kanazawa that evolutionary models of human behaviour can contribute to our understanding of even the most complex social issues. However, Kanazawa’s case study, of what he refers to as ‘World War III’, rests on a flawed theoretical argument, lacks empirical backing, and holds little in the way of explanatory power.

This paper combines regional anthropological comparison, historical linguistics and phylogenetic comparative methodology (PCM) concerning the analysis of sibling terminology in order to address the historical relationships between the languages of the three South African Khoisan families, Kx’a, Tuu and Khoe-Kwadi. We look first at the ways how siblings are grouped into kin classes and secondly how sibling terms as lexical items are linguistically related in and between these families. Their demonstrable internal linguistic relationships imply original family-specific sibling terminologies with relevant lexemes as part of the proto-languages used within a social culture of the proto-societies (cf. Murdock 1949: 346f.; Elmendorf 1961: 365; Jordan 2011: 299). Our hypotheses for proto-terminologies, contact scenarios and trajectories of change are finally submitted to PCM probability tests. By trying to detect signals of genealogical or contact relationships we hope to contribute to the reconstruction of pre-historical processes in the Kalahari Basin, including testing hypotheses found in the previous literature, among them the claim about a deep structural unity of Khoisan kinship systems.

Background: Archaeologists and anthropologists have long recognized that different cultural complexes may have distinct descent histories, but they have lacked analytical techniques capable of easily identifying such incongruence. Here, we show how Bayesian phylogenetic analysis can be used to identify incongruent cultural histories. We employ the approach to investigate Iranian tribal textile traditions.Methods: We used Bayes factor comparisons in a phylogenetic framework to test two models of cultural evolution: the hierarchically integrated system hypothesis and the multiple coherent units hypothesis. In the hierarchically integrated system hypothesis, a core tradition of characters evolves through descent with modification and characters peripheral to the core are exchanged among contemporaneous populations. In the multiple coherent units hypothesis, a core tradition does not exist. Rather, there are several cultural units consisting of sets of characters that have different histories of descent.Results: For the Iranian textiles, the Bayesian phylogenetic analyses supported the multiple coherent units hypothesis over the hierarchically integrated system hypothesis. Our analyses suggest that pile-weave designs represent a distinct cultural unit that has a different phylogenetic history compared to other textile characters.Conclusions: The results from the Iranian textiles are consistent with the available ethnographic evidence, which suggests that the commercial rug market has influenced pile-rug designs but not the techniques or designs incorporated in the other textiles produced by the tribes. We anticipate that Bayesian phylogenetic tests for inferring cultural units will be of great value for researchers interested in studying the evolution of cultural traits including language, behavior, and material culture.

Kinship is a fundamental and universal aspect of the structure of human society. The kinship category of ‘grandparents’ is socially salient, owing to grandparents’ investment in the care of the grandchildren as well as to older generations’ control of wealth and cultural knowledge, but the evolutionary dynamics of grandparent terms has yet to be studied in a phylogenetically explicit context. Here, we present the first phylogenetic comparative study of grandparent terms by investigating 134 languages in Pama–Nyungan, an Australian family of hunter–gatherer languages. We infer that proto-Pama–Nyungan had, with high certainty, four separate terms for grandparents. This state then shifted into either a two-term system that distinguishes the genders of the grandparents or a three-term system that merges the ‘parallel’ grandparents, which could then transition into a different three-term system that merges the ‘cross’ grandparents. We find no support for the co-evolution of these systems with either community marriage organisation or post-marital residence. We find some evidence for the correlation of grandparent and grandchild terms, but no support for the correlation of grandparent and cross-cousin terms, suggesting that grandparents and grandchildren potentially form a single lexical category but that the entire kinship system does not necessarily change synchronously.