Cultural group selection has been proposed as an explanation for humans’ highly cooperative nature. This theory argues that social learning mechanisms, combined with rewards and punishment, can stabilise any group behaviour, cooperative or not. Equilibrium selection can then operate, resulting in cooperative groups outcompeting less-cooperative groups. This process may explain the widespread cooperation between non-kin observed in humans, which is sometimes claimed to be altruistic. This review explores the assumptions of cultural group selection to assess whether it provides a convincing explanation for human cooperation. Although competition between cultural groups certainly occurs, it is unclear whether this process depends on specific social learning mechanisms (e.g. conformism) or a norm psychology (to indiscriminately punish norm-violators) to stabilise groups at different equilibria as proposed by existing cultural group selection models. Rather than unquestioningly adopt group norms and institutions, individuals and groups appear to evaluate, design and shape them for self-interested reasons (where possible). As individual fitness is frequently tied to group fitness, this often coincides with constructing group-beneficial norms and institutions, especially when groups are in conflict. While culture is a vital component underlying our species’ success, the extent to which current conceptions of cultural group selection reflect human cooperative evolution remains unclear.

Interaction between members of culturally distinct (ethnic) groups is an important driver of the evolutionary dynamics of human culture, yet relevant mechanisms remain underexplored. For example, cultural loss resulting from integration with culturally distinct immigrants or colonial majority populations remains a topic whose political salience exceeds our understanding of mechanisms that may drive or impede it. For such dynamics, one mediating factor is the ability to interact successfully across cultural boundaries (cross-cultural competence). However, measurement difficulties often hinder its investigation. Here, simple field methods in a uniquely suited Amazonian population and Bayesian item–response theory models are used to derive the first experience-level measure of cross-cultural competence, as well as evidence for two developmental paths: cross-cultural competence may emerge as a side effect of adopting out-group cultural norms, or it may be acquired while maintaining in-group norms. Ethnographic evidence suggests that the path taken is a likely consequence of power differences in inter- vs intra-group interaction. The former path, paralleling language extinction, may lead to cultural loss; the latter to cultural sustainability. Recognition of such path-dependent effects is vital to theory of cultural dynamics in humans and perhaps other species, and to effective policy promoting cultural diversity and constructive inter-ethnic interaction.

Archaeolinguistics, a field which combines language reconstruction and archaeology as a source of information on human prehistory, has much to offer to deepen our understanding of the Neolithic and Bronze Age in Northeast Asia. So far, integrated comparative analyses of words and tools for textile production are completely lacking for the Northeast Asian Neolithic and Bronze Age. To remedy this situation, here we integrate linguistic and archaeological evidence of textile production, with the aim of shedding light on ancient population movements in Northeast China, the Russian Far East, Korea and Japan. We show that the transition to more sophisticated textile technology in these regions can be associated not only with the adoption of millet agriculture but also with the spread of the languages of the so-called ‘Transeurasian’ family. In this way, our research provides indirect support for the Language/Farming Dispersal Hypothesis, which posits that language expansion from the Neolithic onwards was often associated with agricultural colonization.

The population history of Japan has been one of the most intensively studied anthropological questions anywhere in the world, with a huge literature dating back to the nineteenth century and before. A growing consensus over the 1980s that the modern Japanese comprise an admixture of a Neolithic population with Bronze Age migrants from the Korean peninsula was crystallised in Kazurō Hanihara's influential ‘dual structure hypothesis’ published in 1991. Here, we use recent research in biological anthropology, historical linguistics and archaeology to evaluate this hypothesis after three decades. Although the major assumptions of Hanihara's model have been supported by recent work, we discuss areas where new findings have led to a re-evaluation of aspects of the hypothesis and emphasise the need for further research in key areas including ancient DNA and archaeology.

Recent years have seen great interest in the suggestion that between-group aggression and within-group altruism have coevolved. However, these efforts have neglected the possibility that warfare – via its impact on demography – might influence human social behaviours more widely, not just those directly connected to success in war. Moreover, the potential for sex differences in the demography of warfare to translate into sex differences in social behaviour more generally has remained unexplored. Here, we develop a kin-selection model of altruism performed by men and women for the benefit of their groupmates in a population experiencing intergroup conflict. We find that warfare can promote altruistic, helping behaviours as the additional reproductive opportunities winners obtain in defeated groups decrease harmful competition between kin. Furthermore, we find that sex can be a crucial modulator of altruism, with there being a tendency for the sex that competes more intensely with relatives to behave more altruistically and for the sex that competes more intensely with non-relatives in defeated groups to receive more altruism. In addition, there is also a tendency for the less-dispersing sex to both give and receive more altruism. We discuss implications for our understanding of observed sex differences in cooperation in human societies.

The Tungusic languages form a language family spoken in Xinjiang, Siberia, Manchuria and the Russian Far East. There is a general consensus that these languages are genealogically related and descend from a common ancestral language, conventionally called ‘Proto-Tungusic’. However, the exact geographical location where the ancestral speakers of Proto-Tungusic originated from is subject to debate. Here we take an unprecedented approach to this problem, by integrating linguistic, archaeological and genetic evidence in a single study. Our analysis of ancient DNA suggests genetic continuity between an ancient Amur genetic lineage and the contemporary speakers of the Tungusic languages. Adding an archaeolinguistic perspective, we infer that the most plausible homeland for the speakers of Proto-Tungusic is the region around Lake Khanka in the Russian Far East. Our study pushes the field forward in answering the tantalizing question about the location of the Tungusic homeland and in illustrating how these three disciplines can converge into a holistic approach to the human past.

Parental investment theory predicts that biases in investment favour migration by driving some of the sibling group to disperse for resources. Here we test hypotheses arising from this theory to explain patterns of rural–urban migration in south-central Ethiopia considering familial and individual strategies. We focus on the migration of low-skilled men, predicting two scenarios based on a low level of resource availability. Firstly, last-born sons will be more likely to migrate in order to offset their intra-household disadvantage when resources are limited (sibling competition). Alternatively, in households facing livelihood insecurity, older sons will migrate in order to free resources for their younger dependant brothers (reflecting sibling cooperation). Demographic, economic and relational data were collected from 217 families of male migrants, including information for 830 male adults. We performed multivariate analyses, including Bayesian generalised linear models and mixed models, to analyse quantitative data with a focus on household and individual likelihood of out-migration. Consistent with the predictions from parental investment theory, migration is dependent on intra-household resource allocation. Depending on the stage of the family cycle and livelihood context, families and individuals present different strategies: labour migration may result from sibling competition or from cooperation for resource enhancement.

One of the difficulties with cultural group selection theory highlighted in the review by Smith (2020, Evol. Hum. Sci., 2, e7) is its inability to separate the evolutionary effects of selection of cultural traits based on biological fitness (Cultural Selection 1) from the effects of selection based on cultural fitness (Cultural Selection 2). Confusing these two processes can hinder the integration of adaptive explanations for human behaviour, which focus on biological fitness, and cultural evolution explanations, which often focus on social transmission. Recent empirical work is starting to bridge this gap, but progress in mathematical modelling has been considerably slower. Here, I suggest that modellers can contribute to achieving this integration by further developing models of Cultural Selection 1, where behaviours are influenced by culturally inherited traits selected on the basis of their effects on biological fitness. These models should build on existing social evolution theory methods and replace genetic relatedness with cultural relatedness, that is the probability that two individuals share a cultural variant.

The debate on (cultural) group selection regularly suffers from an inclusive fitness overdose. The classical view is that all group selection is kin selection, and that Hamilton's rule works for all models. I claim that not all group selection is kin selection, and that Hamilton's rule does not always get the direction of selection right. More importantly, I will argue that the paper by Smith (2020; Cultural group selection and human cooperation: a conceptual and empirical review. Evolutionary Human Sciences, 2) shows that inclusive fitness is not particularly relevant for much of the empirical evidence relating to the question whether or not cultural group selection shaped human behaviour.

The ‘farming/language dispersal hypothesis’ was originally developed to explain the spread of the Neolithic economy and material culture into Europe. Recently, this hypothesis has been applied towards explaining the dispersal and divergence of East Asian languages. However, interpretations depend on what prehistoric cultivar is chosen by linguists as having been related with the spread of language. In understanding the appearance of the proto-Koreanic and proto-Japonic languages in Korea, millet and rice, which appeared in Korea around 3500 and 1300 BCE, respectively, have been emphasized by linguists. We assess these linguistic arguments. We first review how European archaeologists have understood the spread of farming into Europe, where the farming/language dispersal hypothesis was originally developed, and how archaeology has wrestled with the issues of diffusion and migration. Then we move on to evaluating linguistic hypotheses about the dispersal and split of proto-Koreanic and proto-Japonic. Our evaluation of the ‘millet hypothesis’ and the ‘rice hypothesis’ suggests that rice is a more plausible candidate for explaining the dispersal of proto-Koreanic to Korea. Meanwhile, viewing the introduction of slender daggers to Korea as another dispersal of language to Korea needs more scrutiny.

Formally, the Farming/Language Dispersal hypothesis as applied to Japan relates to the introduction of agriculture and spread of the Japanese language (between ca. 500 BC–AD 800). We review current data from genetics, archaeology, and linguistics in relation to this hypothesis. However, evidence bases for these disciplines are drawn from different periods. Genetic data have primarily been sampled from present-day Japanese and prehistoric Jōmon peoples (14,000–300 BC), preceding the introduction of rice agriculture. The best archaeological evidence for agriculture comes from western Japan during the Yayoi period (ca. 900 BC–AD 250), but little is known about northeastern Japan, which is a focal point here. And despite considerable hypothesizing about prehistoric language, the spread of historic languages/ dialects through the islands is more accessible but difficult to relate to prehistory. Though the lack of Yayoi skeletal material available for DNA analysis greatly inhibits direct study of how the pre-agricultural Jōmon peoples interacted with rice agriculturalists, our review of Jōmon genetics sets the stage for further research into their relationships. Modern linguistic research plays an unexpected role in bringing Izumo (Shimane Prefecture) and the Japan Sea coast into consideration in the populating of northeastern Honshu by agriculturalists beyond the Kantō region.

Owing to the development of sequencing technology, paleogenomics has become an important source of information on human migration and admixture, complementing findings from archaeology and linguistics. In this study, we retrieved the whole genome and Y chromosome lineage from late Neolithic Honghe individuals in the Middle Amur region in order to provide a bioarchaeological perspective on the origin and expansion of Transeurasian languages in the Amur River basin. Our genetic analysis reveals that the population of the Amur River basin has a stable and continuous genetic structure from the Mesolithic Age up to date. Integrating linguistic and archaeological evidence, we support the hypothesis that the expansion of the Transeurasian language system in the Amur River basin is related to the agricultural development and expansion of the southern Hongshan culture. The spread of agricultural technology resulted in the addition of millet cultivation to the original subsistence mode of fishing and hunting. It played a vital role in the expansion of the population of the region, which in its turn has contributed to the spread of language.

The ‘Northern Eurasian Greenbelt’ (NEG) is the northern forest zone stretching from the Japanese Archipelago to Northern Europe. The NEG has created highly productive biomes for humanity to exploit since the end of the Pleistocene. This research explores how the ecological conditions in northern Eurasia contributed to and affected human migrations and cultural trajectories by synthesizing the complimentary viewpoints of environmental archaeology, Geographic Information Science (GIS), genetics and linguistics. First, the environmental archaeology perspective raises the possibility that the NEG functioned as a vessel fostering people to develop diverse cultures and engage in extensive cross-cultural exchanges. Second, geographical analysis of genomic data on mitochondrial DNA using GIS reveals the high probability that population dynamics in the southeastern NEG promoted the peopling of the Americas at the end of the Pleistocene. Finally, a linguistic examination of environmental- and landscape-related vocabulary of the proto-Turkic language groups enables the outline of their original cultural landscape and natural conditions, demonstrating significant cultural spheres, i.e. from southern Siberia to eastern Inner Mongolia during Neolithization. All of these results combine to suggest that the ecological complex in the southern edge of the NEG in northeast Asia played a significant role in peopling across the continents during prehistory.

The panpipe is a musical instrument composed of end-blown tubes of different lengths tied together. They can be traced back to the Neolithic, and they have been found at prehistoric sites in China, Europe and South America. Panpipes display substantial variation in space and time across functional and aesthetic dimensions. Finding similarities in panpipes that belong to distant human groups poses a challenge to cultural evolution: while some have claimed that their relative simplicity speaks for independent inventions, others argue that strong similarities of specific features in panpipes from Asia, Oceania and South America suggest long-distance diffusion events. We examined 20 features of a worldwide sample of 401 panpipes and analysed statistically whether instrument features can successfully be used to determine provenance. The model predictions suggest that panpipes are reliable provenance markers, but we found an unusual classification error in which Melanesian panpipes are predicted as originating in South America. Although this pattern may be signalling a diffusion event, other factors such as convergence and preservation biases may play a role. Our analyses show the potential of cultural evolution research on music that incorporates material evidence, which in this study includes both archaeological and ethnographic samples preserved in museum collections.

In this article, we model cultural knowledge as a capital in which individuals invest at a cost. To this end, following other models of cultural evolution, we explicitly consider the investments made by individuals in culture as life history decisions. Our aim is to understand what then determines the dynamics of cultural accumulation. We show that culture can accumulate provided it improves the efficiency of people's lives in such a way as to increase their productivity or, said differently, provided the knowledge created by previous generations improves the ability of subsequent generations to invest in new knowledge. Our central message is that this positive feedback allowing cultural accumulation can occur for many different reasons. It can occur if cultural knowledge increases people's productivity, including in domains that have no connection with knowledge, because it frees up time that people can then spend learning and/or innovating. We also show that it can occur if cultural knowledge, and thus the higher level of resources that results from increased productivity, leads individuals to modify their life history decisions through phenotypic plasticity. Finally, we show that it can occur if technical knowledge reduces the effective cost of its own acquisition via division of labour. These results suggest that culture should not be defined only as a set of knowledge and skills but, more generally, as all the capital that has been produced by previous generations and that continues to affect current generations.

Over two decades ago, it was observed that the linguistic affinity of the language spoken by a particular population tended to correlate with the predominant paternal, i.e. Y-chromosomal, lineage found in that population. Such correlations were found to be ubiquitous but not universal, and the striking exceptions to such conspicuous patterns of correlation between linguistic and genetic phylogeography elicit particular interest and beg for clarification. Within the Austroasiatic language family, the Munda languages are a clear-cut case of father tongues, whereas Japanese and Korean are manifestly not. In this study, the cases of Munda and Japanese are juxtaposed. A holistic understanding of these contrasting cases of ethnolinguistic prehistory with respect to the father tongue correlation will first necessitate a brief exposition of the phylogeography of the Y chromosomal lineage O. Then triangulation discloses some contours and particulars of both long lost episodes of ethnolinguistic prehistory.

The origin of the Xiongnu and the Rourans, the nomadic groups that dominated the eastern Eurasian steppe in the late first millennium BC/early first millennium AD, is one of the most controversial topics in the early history of Inner Asia. As debatable is the evidence linking these two groups with the steppe nomads of early medieval Europe, i.e. the Huns and the Avars, respectively. In this paper, we address the problems of Xiongnu–Hun and Rouran–Avar connections from an interdisciplinary perspective, complementing current archaeological and historical research with a critical analysis of the available evidence from historical linguistics and population genetics. Both lines of research suggest a mixed origin of the Xiongnu population, consisting of eastern and western Eurasian substrata, and emphasize the lack of unambiguous evidence for a continuity between the Xiongnu and the European Huns. In parallel, both disciplines suggest that at least some of the European Avars were of Eastern Asian ancestry, but neither linguistic nor genetic evidence provides sufficient support for a specific connection between the Avars and the Asian Rourans.