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At present more than 1600 mustatil have been recorded across Arabia. These monumental ritual structures have been interpreted as markers of territoriality and a key component in constructing and consolidating kinship ties and communal social identities in the Late Neolithic. Perhaps most strikingly, these structures are marked by a homogeneity of architectural form, over a vast geographic area, some 350,000 km2. In AlUla County, ten mustatil have been excavated, including seven by the AAKSA and PAKEP projects. These excavations have revealed chronologically contemporaneous ritual deposits of faunal remains, specifically the horns and upper cranial elements of domesticated sheep, goat, and cattle, as well as wild taxa, such as gazelle and ibex. Despite the overall similarity of architectural form across these examples, the faunal composition of these deposits varies, with some structures marked by higher proportions of wild taxa, whilst others are predominantly composed of cattle and/or caprines. In this paper, we present the data from each of the excavated mustatils and explore the possibility that these assemblages represent the pastoral economies of the group(s) who constructed the mustatil, shedding new light on the various lifeways and herding practices of the 6th and 5th millennia BC. In addition, comparison with contemporary domestic occupation suggests that the appearance of the mustatil marks the emergence of a sacral architectural form in northwest Arabia during the Neolithic, with a clear architectural distinction maintained between the sacred and profane.

This geoarchaeological survey was dedicated to (i) the Umm an-Nar (2700–2000 BCE) settlement site of Dahwa and surrounding areas in the foothills of the Hajar Mountains as well as (ii) the coastal area near Saham on the Batinah coastal plain in northern Oman, the latter without focus on a specific cultural epoch. Stratigraphic sections from the proximal coastal plain provide insights into highly dynamic episodic sedimentation patterns with thick units of variable grain sizes and sorting. In one of the stratigraphic profiles in the town of Saham, a small anthropogenic pit or channel was found, interpreted as a pit hearth used by the Samad culture (300 BCE–100/200 CE) based on granulometry, thin-section analysis, clustered macro-charcoals, amorphous organic remains, as well as luminescence and 14C dating. Our coincidental discovery of this site indicates that there might be abundant traces of the Samad culture buried in the thick alluvium, from a period of hydrologically favourable conditions c. 50–300 CE. The Umm an-Nar dating of the Dahwa archaeological site in the foothills of the Hajar Mountains was confirmed for the first time by luminescence dating, although the low dose rate and high scatter of equivalent doses pose substantial challenges to the regional application of this method.

The Bat landscape of northwestern Oman is one of intermittent archaeological remains and varied ecological conditions. The site has been a center for human activity since the Neolithic, most famously attested by the Early Bronze Age tombs, towers, and settlement of the UNESCO World Heritage zone. This paper presents recent research conducted by the Bat Archaeological Project in reconstructing the site’s third millennium BC cultural landscape and the human-environment interactions that led to its creation and long-term occupation. Three of Bat’s Early Bronze Age environs: the Settlement Slope, al-Khutm, and Rakhat al-Madrh are discussed in view of their ecological, geomorphological, and archaeological contexts. New archaeobotanical and 14C results are presented. These discoveries suggest Bat’s ancient inhabitants sought out and utilized diverse environments in order to establish cultural and ecological resilience within a localized area. Ultimately, we propose an expansion to the traditional oasis model of settlement and agricultural development in southeast Arabia, arguing for a systems-based approach that incorporates roles played by environs beyond the oasis.

This paper attempts to set out a preliminary narrative of changing water exploitation and settlement in Southeast Arabia from the Umm an-Nar period to the Iron Age, with a particular focus on the 4.2ka event. It argues for long-term cultural and adaptive trends that are only now becoming apparent and are relevant to understanding local adaptation strategies to climatic events such as the 4.2ka event. In setting out this narrative, we also aim to show the value of Southeast Arabian data to regional discussions relating to human adaptation to climate change. We argue that lower ground water availability related to aquifer structures would have been a problem for Bronze Age (Umm an-Nar) communities, in particular those living in Central Oman around the Hajar Mountains and would have affected settlement viability in certain climatic conditions, leading to decline in the number and size of settlements after c. 2000BC. We suggest that late Umm an-Nar (2200–2000BC) settlement and agricultural activity over-extended in this area, a development paralleled in Harappan and Mesopotamian communities. These changes would have affected already ancient traditions, for example in relation to the communal ritual monuments. By contrast, for the Northern Emirates karstic aquifers were a crucial factor supporting settlement continuity after the 4.2ka event, in particular in the western coastal areas of Ras al-Khaimah and the area around Dibba on the east coast. It is argued that the distribution of these aquifers is key to understanding the cultural and economic changes associated with the ensuing Wadi Suq period (2000–1600BC). Other processes strengthened the pattern, such as changing interregional exchange patterns and associated overland and maritime routes. By the Iron Age (starting c 1300 BC), it appears that rainfall patterns changed again and settlement density in Central Oman began once again to exceed that of the Northern Emirates. We suggest that this is at least partly linked to the resilience of local communities in dealing with another climate event (3.2ka event) that potentially necessitated the management of climatic patterns that may have included periods of higher and lower rainfall including irregular flooding. Whilst some of the ideas set out here are still quite speculative, they are set out in the belief that further understanding of these changing patterns is crucial for our understanding of long-term adaptation to climate change in this region.

Intra-crystalline protein degradation (IcPD) analysis was undertaken on 80 fossil tooth enamel samples from four taxonomic groups (rhinocerotid, suid, equid, bovid) excavated from two archaeological cave sites in Zambia (Twin Rivers and Mumbwa Caves). Seventy-two (90%) of these fossils showed evidence of closed-system behaviour. The fossils’ relative extent of protein degradation between the sites was consistent with their known ages, with samples from Twin Rivers (Mid-Pleistocene) showing higher levels of degradation than Mumbwa Caves (late Mid-Pleistocene to late Holocene). At Twin Rivers, a potential trend between IcPD and excavation depth was observed, concordant with the working hypothesis of periodic deposition of sediments as slurry flows into a phreatic passage. However, greater depositional and taphonomic complexity was indicated by relatively wide ranges of IcPD values within individual excavation levels. These results are interpreted partly as the consequence of the excavation methods used, alongside reworking within the deposits, which had not previously been recognised. Whilst lack of stratigraphic control limited the investigation of taxonomic effect, one notable difference in the protein breakdown pattern of peptide chain hydrolysis was observed between rhinocerotid in comparison to the other studied taxa. We therefore recommend taxon-specific enamel amino acid geochronologies (AAGs) are developed in future. Whilst lack of comparator datasets meant it was not possible to create a calibrated, enamel AAG for the South-Central African region from these sites, Twin Rivers provides a case study illustrating the complexity of cave formation processes and the importance of direct dating for interpreting archaeological and palaeontological sequences.

The contribution of sediment transport and accumulation to soil formation was investigated in an area characterized by continental sedimentary activity since the Late Pleistocene. The area was the north-eastern portion of the large Quaternary graben represented by the Campania Plain, which is rimmed to the north–east–south by the Mesozoic carbonate Apennine nappes. The plain was filled mainly by products generated by eruptions from the Phlegrean Fields, which were also distributed on the slopes bordering the plain and remobilized toward the adjacent surfaces. Five sites were selected in the area in question. They were studied using morphological features and pertinent characteristics of the mineral soil fraction >2.0 mm, such as their volume and lithological description. Soils were compared to selected lithostratigraphic sequences characterizing the studied area, which were collected from literature and reinterpreted in pedological keys. The results showed that soils derived from the emplacement of Phlegrean primary volcanic materials, such as Campania Ignimbrite (~39–40 ky B.P.) and Neapolitan Yellow Tuff (~15 ky B.P.), with the related weathering products, and from volcanic materials reworked and transported by alluvial/colluvial episodes. The latter formed contrasting soil horizons which, differing in both rock fragment content and lithological composition, testified to the presence of lithological discontinuities. The formation of the horizons in question interrupted the genetic sequence derived from the in situ alteration of the volcanic substrata, suggesting that processes of transport and redistribution of sediments from the adjacent mountain slopes contributed to soil formation. The comparison of the pedostratigraphies with the lithostratigraphic sequences indicated a strong relation between geomorphic and pedogenetic events.

The Vallparadís Section encompasses various geological layers that span a significant chronological range, extending from the latest Early Pleistocene to the early Middle Pleistocene, covering a timeframe from approximately 1.2 to 0.6 Ma. This period holds particular importance, as it coincides with a significant climatic transition known as the Early–Middle Pleistocene Transition, a pivotal phase in Quaternary climatic history. This transition, marked by the shift from a 41,000-year obliquity-driven climatic cycle to a 100,000-year precession-forced cyclicity, had profound effects on the Calabrian carnivorous mammal communities. Notably, the once diverse carnivore guild began to decline across Europe during this period, with their last documented occurrences coinciding with those found within the Vallparadís Section (e.g., Megantereon or Xenocyon). Concurrently, this period witnessed the initial dispersals of African carnivorans into the European landscape (e.g., steppe lions), marking a significant shift in the composition and dynamics of the region’s carnivorous fauna.

This commentary underscores the importance of the recent discovery of the oldest in situ Holocene mangrove sediments found to date in the Caribbean region. It also emphasizes the implications of this finding for understanding postglacial sea level rise and the subsequent recolonization of current Caribbean coasts by mangrove communities. These communities likely survived the last glaciation in small microrefugia located beyond the present continental shelf, from where they expanded to form the present-day mangrove biogeographical patterns.

The Early Pleistocene sites of Orce in southeastern Spain, including Fuente Nueva-3 (FN3), Barranco León (BL) and Venta Micena (VM), provide important insights into the earliest hominin populations and Late Villafranchian large mammal communities. Dated to approximately 1.4 million years ago, FN3 and BL preserve abundant Oldowan tools, cut marks and a human primary tooth, indicating hominin activity. VM, approximately 1.6 million years old, is an outstanding site because it preserves an exceptionally rich assemblage of large mammals and predates the presence of hominins, providing a context for pre-human conditions in the region. Research suggests that both hominins and giant hyenas were essential to the accumulation of skeletal remains at FN3 and BL, with secondary access to meat resources exploited by saber-toothed felids. This aim of this study aims to correlate the relative abundance of large herbivores at these sites with their estimates of Carrying Capacity (CC) and Total Available Biomass (TAB) using the PSEco model, which incorporates survival and mortality profiles to estimate these parameters in paleoecosystems. Our results show: (i) similarities between quarries VM3 and VM4 and (ii) similarities of these quarries with BL-D (level D), suggesting a similar formation process; (iii) that the role of humans would be secondary in BL-D and FN3-LAL (Lower Archaeological Level), although with a greater human influence in FN3-LAL due to the greater presence of horses and small species; and (iv) that FN3-UAL (Upper Archaeological Level) shows similarities with the expected CC values for FN3/BL, consistent with a natural trap of quicksand scenario, where the large mammal species were trapped according to their abundance and body mass, as there is a greater presence of rhinos and mammoths due to the greater weight per unit area exerted by their legs. Given the usefulness of this approach, we propose to apply it first to sites that have been proposed to function as natural traps.

In the northern part of the Niğde (Central Anatolian) Quaternary Bor Basin, stratigraphic sections P1 and P2 were sampled, reaching depths of 11 m and 25 m. The samples were analyzed with thin-section, XRD, and chemical analyses (ICP-MS) to determine their chemical and mineralogical properties. In the study area, partially lithified volcano-sedimentary rocks comprised paleosol, calcrete, gravel, sand, silt, mud, clay, and volcanoclastics such as pumice fall-out. Grain size analyses from the Zengen (P1) and Altunhisar (P2) regions showed very poor sorting and strong positive skewness. The Zengen-area (P1) samples contained rock fragments, calcite, quartz, opal-CT, feldspar, amphibole, pyroxene, biotite, and clay minerals such as smectite, chlorite, illite, palygorskite, and sepiolite. In calcrete zones, however, the amounts of CaO increased, whereas significant decreases in the amounts of SiO2 were observed. Therefore, a negative correlation between SiO2 and CaO was observed. The vertical distributions and behaviors of trace elements in the Zengen-area profile showed variation with the different levels of the P1 section. It is thought that in the Bor Plain, after 17,000 years ago, no lacustrine phase reached a level above the periglacial lake level in the region, reaching this level with the melting of the ice sheets in the area. During the late glacial period, shallow freshwater lacustrine phases and paleosols were identified from 12,500 to 11,000 yr BP in the basin.

Recent technological advancements in spectral imaging core-scanning techniques have proved to be a promising tool to study lake sediments at extremely high resolution. We used this novel analytical approach to scan core AU3 of the Pleistocene Auel maar, Western Germany. The resulting ultra-high-resolution RABD670 spectral index, a proxy for the lake’s primary production, shows an almost complete succession of Greenland Interstadials of the NGRIP ice core chronology back to around 60,000 years. Using the ELSA-20 chronology and its anchor points to the NGRIP record as a stratigraphic basis, we were able to compare and fine-tune prominent climate signals occurring in both regions. This in-depth correlation yields strong evidence that the climates of Greenland and Central Europe were not only strongly coupled on timescales of stadials and interstadials but even on multidecadal scales, showing prominent climate cycles between 20 and 125 years. As climate changes in these regions were ultimately driven by variations in the North Atlantic meridional heat transport, their strong coupling becomes most apparent during cold and arid intervals. In contrast, longer-lasting warmer and more humid phases caused the activation of various regional feedback mechanisms (e.g., soil formation, forest growth), resulting in more complex patterns in the proxy records.

This review, through the collection and comparative analysis of the most recent literature, aims to analyze the new trends in archaeometric analysis and some selected laboratory techniques aimed at determining the provenance, the physical–chemical characteristics, and the state of decay of archaeological finds of different types (ancient manuscripts, paintings, frescoes, and ceramics). In particular, the methodologies and analytical techniques relating to Raman spectroscopy, X-ray fluorescence, laser ablation, IR spectroscopy, LIBS, and Thz spectroscopy were compared and tabulated, with the aim of determining the appropriateness of each technique applied to various archaeological items. This will provide guidelines for the right conservation and restoration strategies. The work was also based on the construction of comparative tables of the consulted scientific literature and on the analysis of the research trends by using the Google Trends app.

The loess–paleosol profile of Máza brickyard in SW Hungary was investigated through multivariate analyses of malacofauna and sedimentological analyses. The aim was to reconstruct the complex developmental history of both sediment and malacofauna. Three age–depth models were calculated, and the best-fit model, the OxCal P-sequence, was chosen for further analysis. The profile overlays the MIS3 and MIS2, beginning at approximately 45,000–50,000 cal BP and ending at the Pleistocene/Holocene boundary. The accumulation rates were two periods of intensive accumulation, equal to those observed in the Bácska Loess Plateau in Hungary, and two periods of decreased accumulation. Between ~38,000 and 31,000 cal BP, a decreased accumulation period was observed in Máza and other profiles from the Bácska Loess Plateau, indicating a common weak accumulation period at the end of MIS3. Correspondence and cluster analyses provided a higher-resolution paleoecological reconstruction, revealing a more detailed picture of the evolution of the studied section. The presence of thermophilous gastropod species with a high contribution to the correspondence analysis was significant in the sections. Although Granaria frumentum, Helicopsis striata, Chondrula tridens, and Pupilla triplicata were not significant species in the Máza malacofauna as a whole, their presence was associated with warming periods and the emergence of open vegetation.

At the end of the Pleistocene as temperatures warmed, new habitats opened up to human occupation as the Fennoscandian Ice Sheet receded. Along the west coast of modern-day Norway, human populations of coastal foragers slowly transitioned from short-term settlement patterns in the Early Mesolithic (ca. 11,500–10,000 cal BP), to more lasting ones during the Late Mesolithic (8500-6000 BP) and Early Neolithic (ca. 6000–5200 BP) as climatic conditions improved and stabilized. Here, using spatially and temporally resolved archaeological observations, paleoclimate data, and a spatiotemporal species distribution model, we test whether a) improvements in climate resulted in expansion of the available human niche space allowing for human population growth, and b) whether increasing population densities and ensuing deprecation of habitat suitability pushed people into occupying successively lower ranked habitats as predicted by the Ideal Free Distribution model. We find that a) climate gradually improved and stabilized during the Holocene, with the effect of improving general habitat suitability, which in turn led to an increase in human population size, b) that immediate proximity to sheltered coastal areas was central to settlement decisions but that c) increasing populations did not drive dispersal patterns into lower ranked habitats. The latter is likely attributable to the general improvements in habitat suitability due to the warming climate and the relative abundance of coastal habitats found in Norway.

At the end of the Pleniglacial and the first half of the Late Glacial period, approximately between 18 and 14 ka BP, rivers of the central and southern parts of the East European Plain had channels up to 10 times as large as the present day channels of the same rivers. These ancient channels, called large meandering palaeochannels, are widespread in river floodplains and low terraces. The hydrological regime of these large rivers is of great interest in terms of the palaeoclimatology of the late Marine Isotope Stage 2 (MIS 2). In this study, we aimed at quantitative estimation of maximum flood discharges of rivers in the Dnepr, Don and Volga basins in the late MIS 2. To approach this, we used massive measurements of the morphometric characteristics of large palaeochannels on topographic maps and remote sensing data—palaeochannel width, meander wavelength and their relationships with river flow parameters. The runoff depth of the maximum flood, which corresponds to the maximum depth of daily snow thaw during the snowmelt period, was obtained for unit basins with an area of 2. The mean value for the southern megaslope of the East European Plain was 44.2 mm/day (6 times the modern value), with 46 mm/day for the Volga River (5.5 times), 45 mm/day (6.3 times) for the Don River and 39 mm/day (8 times the modern value) for the Dnepr River basins. In general, the Dnepr basin was drier than the Don and Volga basins, which corresponds well to the modern distribution of humidity. At the same time, the westernmost part of the Dnepr River basin was relatively wet in the past, and the decrease in humidity from the past to the modern situation was greater there than in the eastern and central regions. The obtained results contradict the prevailing ideas, based mainly on climatic modeling and palynological data, that the climate of Europe was cold and dry during MIS 2. The reason is that palaeoclimatic reconstructions were made predominantly for the LGM epoch (23–20 ka BP). On the East European Plain, the interval 18–14 ka BP is rather poorly studied. Our results of paleoclimatological and palaeohydrological reconstructions showed that the Late Pleniglacial and the first half of the Late Glacial period was characterized by a dramatic increase in precipitation and river discharge relative to the present day.

The significance of birds in the medieval human diet has been greatly explored in Europe. However, there is a lack of systematic analysis of data from Croatia. Avian remains dated to the Late Medieval and Early Modern Periods from five archaeological sites in continental Croatia underwent skeletal and taxonomic analysis. Age groups were determined and sex identification was conducted using visual and X-ray diagnostics. Chicken bone measurements were taken, and the logarithmic size index (LSI) technique was performed. Statistical analysis was applied to explore differences between sites. A total of 694 avian remains were studied, revealing 10 species/genera. Avian remains ranged from 8.88% to 20.32% across sites, with the highest percentage found at the urban site BAN. Hens outnumbered cockerels across all sites, with adult chickens prevailing over immature and subadult ones. Chicken sizes were generally consistent across sites, except for castle MIL, where a larger breed was identified. Cockerels tended to be larger than hens, except for one small-sized spurred specimen. To conclude, bird exploitation complemented the use of other animals in diets. Chickens were vital for eggs and meat, with monasteries excelling in bird husbandry over castles. Inhabitants of urban areas mainly consumed bird meat. Castles showed high status through game and imported birds. The aim of this article was to fill in the gap of information regarding the exploitation and consumption of birds at Croatian sites during the Late Medieval and Early Modern Periods.

Despite more than 100 years of research, a number of questions concerning the evolution of the post-glacial connection between Lake Ladoga, the largest European lake, and the Baltic Sea remain unanswered. In particular, the location and chronological frames of the paleo-outlet from Lake Ladoga in the Holocene remain debatable. Paleolimnological studies were performed in small lakes in the northern part of the Karelian Isthmus (NW Russia), where the outlet from Lake Ladoga, the Heinjoki Strait, is thought to have existed until the lake drained to the south due to the tilting of its basin. The presence of the indicative “Ladoga species” (e.g., Aulacoseira islandica, Achnanthes joursacense, Cymbella sinuata, Ellerbeckia arenaria, Navicula aboensis, N. jaernefeltii, N. jentzschii, etc.) in the diatom assemblages is used as evidence for the influence of Lake Ladoga during the accumulation of coarse-grained sediments at the bottom of the ancient channel. It also confirms the functioning of the hypothetical northern local branch of the strait. Decreased abundances of the “Ladoga species” and the onset of the accumulation of fine-grained sediments suggest that the water discharge via this paleo-outlet rapidly reduced starting from ca. 4100 cal BP. The termination of the functioning of the Heinjoki Strait is recorded as an abrupt disappearance of the indicative taxa from the diatom record. This was dated to ca. 3500–3200 cal BP, which corresponds to the estimated ages of the birth of the River Neva, the present outlet from Lake Ladoga.

With its linguistic and cultural diversity, Austronesia is important in the study of evolutionary forces that generate and maintain cultural variation. By analysing publicly available datasets, we have identified four classes of cultural features in Austronesia and distinct clusters within each class. We hypothesized that there are differing modes of transmission and patterns of variation in these cultural classes and that geography alone would be insufficient to explain some of these patterns of variation. We detected relative differences in the verticality of transmission and distinct patterns of cultural variation in each cultural class. There is support for pulses and pauses in the Austronesian expansion, a west-to-east increase in isolation with explicable exceptions, and correspondence between linguistic and cultural outliers. Our results demonstrate how cultural transmission and patterns of variation can be analysed using methods inspired by population genetics.

The maintenance of cross-cultural variation and arbitrary traditions in human populations is a key question in cultural evolution. Conformist transmission, the tendency to follow the majority, was previously considered central to this phenomenon. However, recent theory indicates that cognitive biases can greatly reduce its ability to maintain traditions. Therefore, we expanded prior models to investigate two other ways that cultural variation can be sustained: payoff-biased transmission and norm reinforcement. Our findings predict that both payoff-biased transmission and reinforcement can enhance conformist transmission's ability to maintain traditions. However, payoff-biased transmission can only sustain cultural variation if it is functionally related to environmental factors. In contrast, norm reinforcement readily generates and maintains arbitrary cultural variation. Furthermore, reinforcement results in path-dependent cultural dynamics, meaning that historical traditions influence current practices, even though group behaviours have changed. We conclude that environmental variation probably plays a role in functional cultural traditions, but arbitrary cultural variation is more plausibly due to the reinforcement of norm compliance.

Understanding and predicting human cooperative behaviour and belief dynamics remains a major challenge both from the scientific and practical perspectives. Because of the complexity and multiplicity of material, social and cognitive factors involved, both empirical and theoretical work tends to focus only on some snippets of the puzzle. Recently, a mathematical theory has been proposed that integrates material, social and cognitive aspects of behaviour and beliefs dynamics to explain how people make decisions in social dilemmas within heterogeneous groups. Here we apply this theory in two countries, China and Spain, through four long-term behavioural experiments utilising the Common Pool Resources game and the Collective Risk game. Our results show that material considerations carry the smallest weight in decision-making, while personal norms tend to be the most important factor. Empirical and normative expectations have intermediate weight in decision-making. Cognitive dissonance, social projection, logic constraints and cultural background play important roles in both decision-making and beliefs dynamics. At the individual level, we observe differences in the weights that people assign to factors involved in the decision-making and belief updating process. We identify different types of prosociality and rule-following associated with cultural differences, various channels for the effects of messaging, and culturally dependent interactions between sensitivity to messaging and conformity. Our results can put policy and information design on firmer ground, highlighting the need for interventions tailored to the situation at hand and to individual characteristics. Overall, this work demonstrates the theoretical and practical power of the theory in providing a more comprehensive understanding of human behaviour and beliefs.

Humans show remarkable differences in social behaviour between families, groups, communities and cultures, whereas such group-level within-species variation in socio-behavioural propensities is typically overlooked in other species. Studies on intraspecific variation in animal social structures are needed to inform an evolutionary account of human sociality. Here, we study multiple independent bonobo populations (n = 6) in zoological settings to investigate if and how bonobos (n = 70) show group-specific signatures in sociality. By applying tailored Bayesian statistical methods, we find that beyond individual and dyadic variation, the groups substantially differ from each other in core dimensions of great ape sociality: social proximity, grooming and play. Moreover, the groups’ network structures are distinct regarding cohesiveness and clustering, with some groups forming cohesive wholes, while others showcasing high levels of sub-grouping. Overall, while there is consistent evidence of differences in sociality between the groups, the patterns of cohesiveness and clustering are not consistent across the networks. This suggests that rather than groups having different levels of sociality, different patterns of sociality exist in each group. These findings warrant caution with characterising bonobos’ behavioural phenotype at the species level, and identify an essential source of variation that needs to be integrated in phylogenetic analyses.

Previous research in the evolutionary and psychological sciences has suggested that markers or tags of ethnic or group membership may help to solve cooperation and coordination problems. Cheating remains, however, a problem for these views, insofar as it is possible to fake the tag. While evolutionary psychologists have suggested that humans evolved the propensity to overcome this free rider problem, it is unclear how this module might manifest at the group level. In this study, we investigate the degree to which native and non-native speakers of accents – which are candidates for tags of group membership – spoken in the UK and Ireland can detect mimicry. We find that people are, overall, better than chance at detecting mimicry, and secondly we find substantial inter-group heterogeneity, suggesting that cultural evolutionary processes drive the manifestations of cheater detection. We discuss alternative explanations and suggest avenues of further inquiry.

The transition to sedentary agricultural societies in northern China fuelled considerable demographic growth from 5000 to 2000 BC. In this article, we draw together archaeobotanical, zooarchaeological and bioarchaeological data and explore the relationship between several aspects of this transition, with an emphasis on the millet-farming productivity during the Yangshao period and how it facilitated changes in animal husbandry and consolidation of sedentism. We place the period of domestication (the evolution of non-shattering, initial grain size increase and panicle development) between 8300 and 4300 BC. The domestication and post-domestication of foxtail (Setaria italica) and broomcorn (Panicum miliaceum) millet increased their productivity substantially, with much greater rate of change than for rice (Oryza sativa). However, millets are significantly less productive per hectare than wet rice farming, a point reflected in the greater geographical expanse of northern Neolithic millet cultures (5000–3000 BC) in comparison with their Yangtze rice-growing counterparts. The domestication of pigs in the Yellow River region is evidenced by changes in their morphology after 6000 BC, and a transition to a millet-based diet c. 4500–3500 BC. Genetic data and isotopic data from dogs indicate a similar dietary transition from 6000 to 4000 BC, leading to new starch-consuming dog breeds. Significant population increase associated with agricultural transitions arose predominately from the improvement of these crops and animals following domestication, leading to the formation of the first proto-urban centres and the demic-diffusion of millet agriculture beyond central northern China between 4300–2000 BC.

Natural selection should favour litter sizes that optimise trade-offs between brood-size and offspring viability. Across the primate order, the modal litter size is one, suggesting a deep history of selection favouring minimal litters in primates. Humans, however – despite having the longest juvenile period and slowest life-history of all primates – still produce twin births at appreciable rates, even though such births are costly. This presents an evolutionary puzzle. Why is twinning still expressed in humans despite its cost? More puzzling still is the discordance between the principal explanations for human twinning and extant empirical data. Such explanations propose that twinning is regulated by phenotypic plasticity in polyovulation, permitting the production of larger sib sets if and when resources are abundant. However, comparative data suggest that twinning rates are actually highest in poorer economies and lowest in richer, more developed economies. We propose that a historical dynamic of gene–culture co-evolution might better explain this geographic patterning. Our explanation distinguishes geminophilous and geminophobic cultural contexts, as those celebrating twins (e.g. through material support) and those hostile to twins (e.g. through sanction of twin-infanticide). Geminophilous institutions, in particular, may buffer the fitness cost associated with twinning, potentially reducing selection pressures against polyovulation. We conclude by synthesising a mathematical and empirical research programme that might test our ideas.

Hunter–gatherer populations underwent a mass extinction in the Neolithic, and in present times face challenges such as explicit sedentarisation policies. An exception is in Nepal, where the nomadic Raute people receive monthly governmental individual payments. One consequence of the money transfers has been a significant increase in alcohol consumption, with nearly all individuals drinking industrially produced alcohol. Here we investigate the Raute demography based on a full census of 144 individuals. We show that the Raute exhibit the short life expectancies typical of other hunter–gatherer populations from Africa, Asia and America. Bayesian survival trajectory analysis demonstrated that heavy drinking by either parent substantially reduces offspring survival to age 15. Bayesian regressions revealed a significant effect of heavy drinking on maternal fertility by decreasing the number of living children and reducing the proportion of live children at the end of maternal reproductive life. Although the absence of data prior to monetary support precludes a direct assessment of long-term demographic trends, relatively stable population sizes over the last decades and a fertility rate close to the replacement rate rule out an imminent population crash. Further studies are required to elucidate the Rautes’ origins and relationship with other nomadic people in the region.

Infant carrying and more generally load carrying may impact bipedal locomotion and thus the energy cost of the daily activities, in living people but also in our ancestors. In order to improve our knowledge of infant carrying strategies we investigate the biomechanics of infant carrying in a non-mechanised group. The Qashqai are nomadic people who still carry loads and infants habitually without any daily assistance in varied natural environments. Our analysis focuses on the sagittal kinematics using a high-speed camera (joint angles, speed, position of the centre of mass) and kinetics (ground reaction forces and displacement of the centre of mass) using a six-degree of freedom force plate. We assessed the unloaded and loaded (infant) walking of 26 Qashqai women, living in the Fars province (Iran). The results demonstrate that different mechanisms of walking exist that are related to the mode of carrying and the weight of the infant, by which step length, walking speed and the lower limb angles are not affected. The displacement of the total centre of mass remains unchanged. This supports the hypothesis that the Qashqai have developed mechanisms of load carrying that limit the increase in energy consumption. This could be related to the usual high level of daily activity.

According to the Trivers–Willard hypothesis (TWH), when the mother's condition around conception influences the future reproductive success of male and female offspring differently, the adjustment of offspring sex ratio (SR) to maternal condition will increase the parents’ fitness. The TWH has been tested in several taxa, including humans where socioeconomic status as an index of condition has been widely used. The results are inconsistent, possibly because the preconditions of the TWH are not always met. To investigate the preconditions and prediction of the TWH in the contemporary Hungarian population, we collected data by an online questionnaire on self-perceived childhood living standard, the number of children and the sex of the respondents’ siblings. We found no sex-specific relationship between reproductive success and childhood living standards, thus the precondition of the TWH was not met. We found no relationship between socioeconomic status and offspring SR when data from the whole country was used, but there was a tendency in the predicted direction when we used data from Budapest and considered the SR of only those family members who were born under similar conditions. Similar approaches should be preferred in the future to avoid noise caused by changing status during the reproductive lifespan.

The mate guarding theory of conservative clothing posits that veiling reduces women's physical allure and sexual attractiveness, thereby diminishing men's attraction towards them and deterring potential rivals for a woman's partner. This theory argues that the importance of veiling is influenced by ecological factors in a way that it is of higher importance to control women's sexuality in harsher environments to secure paternal investment. A prediction of this theory is that the importance of veiling should be influenced by community size, where individuals’ reputations, specifically men's, might have different weightings, and their perceived sense of controlling a partner's activity may differ. Using pre-existing data from seven countries encompassing over 9000 individuals, the current study explored the association of town size and importance of veiling for women. Results showed a U-shaped relationship where in small towns and large cities, individuals, specifically men, give more importance to the veiling of women. This finding not only has multiple implications in terms of the effect of community size on male policing behaviours of women and sexual restrictions, but it also might point to a wider relationship regarding the association of community size and moral values.

People willingly follow norms and values, often incurring material costs. This behaviour supposedly stems from evolved norm psychology, contributing to large-scale cooperation among humans. It has been argued that cooperation is influenced by two types of norms: injunctive and descriptive. This study theoretically explores the socialisation of humans under these norms. Our agent-based model simulates scenarios where diverse agents with heterogeneous norm psychologies engage in collective action to maximise their utility functions that capture three motives: gaining material payoff, following injunctive and descriptive norms. Multilevel selective pressure drives the evolution of norm psychology that affects the utility function. Further, we develop a model with exapted conformity, assuming selective advantage for descriptive norm psychology. We show that norm psychology can evolve via cultural group selection. We then identify two normative conditions that favour the evolution of norm psychology, and therefore cooperation: injunctive norms promoting punitive behaviour and descriptive norms. Furthermore, we delineate different characteristics of cooperative societies under these two conditions and explore the potential for a macro transition between them. Together, our results validate the emergence of large-scale cooperative societies through social norms and suggest complementary roles that conformity and punishment play in human prosociality.

Multiple proposals suggest that xenophobia increases when infectious disease threats are salient. The current longitudinal study tested this hypothesis by examining whether and how anti-immigrant sentiments varied in the Netherlands across four time points during the COVID-19 pandemic (May 2020, February 2021, October 2021 and June 2022 through Flycatcher.eu). The results revealed that (1) anti-immigrant sentiments were no higher in early assessments, when COVID-19 hospitalizations and deaths were high, than in later assessments, when COVID-19 hospitalizations were low, and (2) within-person changes in explicit disease concerns and disgust sensitivity did not relate to anti-immigrant sentiments, although stable individual differences in disgust sensitivity did. These findings suggest that anecdotal accounts of increased xenophobia during the pandemic did not generalize to the population sampled from here. They also suggest that not all increases in ecological pathogen threats and disease salience increase xenophobia.

The expensive-tissue hypothesis (ETH) posited a brain–gut trade-off to explain how humans evolved large, costly brains. Versions of the ETH interrogating gut or other body tissues have been tested in non-human animals, but not humans. We collected brain and body composition data in 70 South Asian women and used structural equation modelling with instrumental variables, an approach that handles threats to causal inference including measurement error, unmeasured confounding and reverse causality. We tested a negative, causal effect of the latent construct ‘nutritional investment in brain tissues’ (MRI-derived brain volumes) on the construct ‘nutritional investment in lean body tissues’ (organ volume and skeletal muscle). We also predicted a negative causal effect of the brain latent on fat mass. We found negative causal estimates for both brain and lean tissue (−0.41, 95% CI, −1.13, 0.23) and brain and fat (−0.56, 95% CI, −2.46, 2.28). These results, although inconclusive, are consistent with theory and prior evidence of the brain trading off with lean and fat tissues, and they are an important step in assessing empirical evidence for the ETH in humans. Analyses using larger datasets, genetic data and causal modelling are required to build on these findings and expand the evidence base.

The human sciences should seek generalisations wherever possible. For ethical and scientific reasons, it is desirable to sample more broadly than ‘Western, educated, industrialised, rich, and democratic’ (WEIRD) societies. However, restricting the target population is sometimes necessary; for example, young children should not be recruited for studies on elderly care. Under which conditions is unrestricted sampling desirable or undesirable? Here, we use causal diagrams to clarify the structural features of measurement error bias and target population restriction bias (or ‘selection restriction’), focusing on threats to valid causal inference that arise in comparative cultural research. We define any study exhibiting such biases, or confounding biases, as weird (wrongly estimated inferences owing to inappropriate restriction and distortion). We explain why statistical tests such as configural, metric and scalar invariance cannot address the structural biases of weird studies. Overall, we examine how the workflows for causal inference provide the necessary preflight checklists for ambitious, effective and safe comparative cultural research.

The analysis of ‘moderation’, ‘interaction’, ‘mediation’ and ‘longitudinal growth’ is widespread in the human sciences, yet subject to confusion. To clarify these concepts, it is essential to state causal estimands, which requires the specification of counterfactual contrasts for a target population on an appropriate scale. Once causal estimands are defined, we must consider their identification. I employ causal directed acyclic graphs and single world intervention graphs to elucidate identification workflows. I show that when multiple treatments exist, common methods for statistical inference, such as multi-level regressions and statistical structural equation models, cannot typically recover the causal quantities we seek. By properly framing and addressing causal questions of interaction, mediation, and time-varying treatments, we can expose the limitations of popular methods and guide researchers to a clearer understanding of the causal questions that animate our interests.

Theorists of human evolution are interested in understanding major shifts in human behavioural capacities (e.g. the creation of a novel technological industry, such as the Acheulean). This task faces empirical challenges arising both from the complexity of these events and the time-depths involved. However, we also confront issues of a more philosophical nature, such as how to best think about causation and explanation. This article considers such fundamental questions from the perspective of a prominent theory of causation in the philosophy of science literature, namely, the interventionist theory of causation. A signature feature of this framework is its recognition of a family of distinct types of causes. We set out several of these causal notions and show how they can contribute to explaining transitions in human behavioural complexity. We do so, first, in a preliminary way, and then in a more detailed way, taking the origins of behavioural modernity as our extended case study. We conclude by suggesting some ways in which the approach developed here might be elaborated and extended.

Confounding bias arises when a treatment and outcome share a common cause. In randomised controlled experiments (trials), treatment assignment is random, ostensibly eliminating confounding bias. Here, we use causal directed acyclic graphs to unveil eight structural sources of bias that nevertheless persist in these trials. This analysis highlights the crucial role of causal inference methods in the design and analysis of experiments, ensuring the validity of conclusions drawn from experimental data.

Causal inference requires contrasting counterfactual states under specified interventions. Obtaining these contrasts from data depends on explicit assumptions and careful, multi-step workflows. Causal diagrams are crucial for clarifying the identifiability of counterfactual contrasts from data. Here, I explain how to use causal directed acyclic graphs (DAGs) to determine if and how causal effects can be identified from non-experimental observational data, offering practical reporting tips and suggestions to avoid common pitfalls.

The frequency of left-handedness in humans is ~10% worldwide and slightly higher in males than females. Twin and family studies estimate the heritability of human handedness at around 25%. The low but substantial frequency of left-handedness has been suggested to imply negative frequency-dependent selection, e.g. owing to a ‘surprise’ advantage of left-handers in combat against opponents more used to fighting right-handers. Because such game-theoretic hypotheses involve social interaction, here we perform an analysis of the evolution of handedness based on kin-selection, which is understood to play a major role in the evolution of social behaviour generally. We show that: (1) relatedness modulates the balance of right-handedness vs. left-handedness, according to whether left-handedness is marginally selfish vs. marginally altruistic; (2) sex differences in relatedness to social partners may drive sex differences in handedness; (3) differential relatedness of parents and offspring may generate parent–offspring conflict and sexual conflict leading to the evolution of maternal and paternal genetic effects in relation to handedness; and (4) differential relatedness of maternal-origin vs. paternal-origin genes may generate intragenomic conflict leading to the evolution of parent-of-origin-specific gene effects – such as ‘genomic imprinting’ – and associated maladaptation.

With the rise of dating apps, people have access to a vast pool of potential partners at their fingertips. The present study examined how various factors would predict an individual's dating decisions in a dating app-analogue study. Participants (N = 269) first completed some trait measures and then a mock-dating task in which they judged the attractiveness of a series of targets and then decided whether to match with the target or not. Their memories for the targets were tested on the second day. People who were more (vs. less) short-term oriented were more likely to match with short-term-oriented targets. Moral disgust and sexual disgust negatively predicted the matching with short-term-oriented targets. Contrary to our hypothesis, we did not find support that people with higher (vs. lower) pathogen disgust sensitivity would selectively match with more attractive targets. Exploratory analyses showed that people who were more (vs. less) short-term oriented, more (vs. less) sexually attractive, or had higher (v. lower) mate value, were more likely to match with targets they considered as attractive. Finally, people have better memories of the faces they chose to match than to not match. Implications for mating research and limitations are discussed.

The prevalence of divorce in both parental and grandparental generations has led to a rise in the number of children who now have families that include both biological and step-grandparents. Despite the thorough examination of biological grandparents’ contributions in the recent literature, there remains a scarcity of studies focusing on the investment of step-grandparents. Using population-based data from a sample of 2494 parents in Germany, we assessed grandparental investment through financial support and assistance with childcare of grandparents (N = 4238) and step-grandparents (N = 486). The study revealed that step-grandparents provided lower levels of investment in their grandchildren compared with biological grandparents. Furthermore, the study identified that a longer duration of co-residence between step-grandparents and parents earlier in life did not correspond to an increase or decrease in step-grandparental investment. However, investment by separated biological grandparents increased with the increasing length of co-residence with parents. In line with the scarce literature on step-grandparental investment, these findings indicate that mating effort may be the most important motivation for step-grandparental investment.

Many institutions claim that bride price – where the groom's family transfers wealth to the bride's family at marriage – harms women. Owing to its long-term engagement with communities that practise bride price, ethnography is well placed to identify causal mechanisms at play in this issue, and there is a substantial literature on its effects in a variety of world regions, including Melanesia. Here, we condense this literature, drawing out key causal arguments made about bride price in various Melanesian societies. This reveals a complex, multi-causal picture: rather than being singularly harmful, bride price may involve a mixture of drawbacks and benefits, making it a double-edged sword with contested implications. Bride price may constrain women's options before and during the marriage but also serves as a safety net that enhances their status. Its effects are probably influenced by many other variables, including age, kinship networks and residence structures. These dynamics have been transformed by conversion to Christianity, the (post-)colonial state, market integration, urbanisation and formal education, often yielding ambiguous outcomes. Rather than reducing ethnography to a collection of datapoints, we show that it can serve as a source of verbal arguments that can be used to challenge reductive narratives about sensitive issues and to formulate hypotheses for testing with quantitative data.

An increasingly common phenomenon in modern work and school settings is individuals taking on too many tasks and spending effort without commensurate rewards. Such an imbalance of efforts and rewards leads to myriad negative consequences, such as burnout, anxiety and disease. Here, we develop a model to explain how such effort–reward imbalances can come about as a result of biased social learning dynamics. Our model is based on a phenomenon that on some US college campuses is called ‘the floating duck syndrome’. This phrase refers to the social pressure on individuals to advertise their successes but hide the struggles and the effort put in to achieve them. We show that a bias against revealing the true effort results in social learning dynamics that lead others to underestimate the difficulty of the world. This in turn leads individuals to both invest too much total effort and spread this effort over too many activities, reducing the success rate from each activity and creating effort–reward imbalances. We also consider potential ways to counteract the floating duck effect: we find that solutions other than addressing the root cause, biased observation of effort, are unlikely to work.

Results from cultural evolutionary theory often suggest that social learning can lead cultural groups to differ markedly in the same environment. Put differently, cultural evolutionary processes can in principle stabilise behavioural differences between groups, which in turn could lead selection pressures to vary across cultural groups. Separating the effects of culture from other confounds, however, is often a daunting and sometimes intractable challenge for the working empiricist. To meet this challenge, we exploit a cultural border dividing Switzerland in ways that are independent of institutional, environmental and genetic variation. Using a regression discontinuity design, we estimate discontinuities at the border in terms of preferences related to fertility and mortality, the two basic components of genetic fitness. We specifically select six referenda related to health and fertility and analyse differences in the proportion of yes votes across municipalities on the two sides of the border. Our results show multiple discontinuities and thus indicate a potential role of culture in shaping stable differences between groups in preferences and choices related to individual health and fertility. These findings further suggest that at least one of the two groups, in order to uphold its cultural values, has supported policies that could impose fitness costs on individuals relative to the alternative policy under consideration.

While humans are highly cooperative, they can also behave spitefully. Yet spite remains understudied. Spite can be normatively driven and while previous experiments have found some evidence that cooperation and punishment may spread via social learning, no experiments have considered the social transmission of spiteful behaviour. Here we present an online experiment where, following an opportunity to earn wealth, we asked participants to choose an action towards an anonymous partner across a full spectrum of social behaviour, from spite to altruism. In accordance with cultural evolutionary theory, participants were presented with social information that varied in source and content. Across six conditions, we informed participants that either the majority or the highest earner had chosen to behave spitefully, neutrally or altruistically. We found an overall tendency towards altruism, but at lower levels among those exposed to spite compared with altruism. We found no difference between social information that came from the majority or the highest earner. Exploratory analysis revealed that participants’ earnings negatively correlated with altruistic behaviour. Our results contrast with previous literature that report high rates of spite in experimental samples and a greater propensity for individuals to copy successful individuals over the majority.

Cohort replacement – the replacement in a population of older cohorts by their successors who developed under different conditions – is an important process behind cultural change. Research on public opinion indicates that a large proportion of aggregate change is the result of cohort replacement rather than of individuals changing their minds. However, some publicly salient issues, like gay rights, appear to be exceptions. Why different issues show different patterns of change is not well understood. In this paper, we investigate whether opinions on sensitive – that is, hard to discuss – issues might change differently than opinions on less sensitive issues. We use data from the 1981–2020 World Values Surveys and newly collected data on the sensitivity of survey items to compare aggregate changes in public opinion on 56 survey items in eight countries. Our key finding is that survey items on more sensitive issues seem to change more through cohort replacement.

The number of studies examining gender differences in the social relationship rewards associated with costly religious practice has been surprisingly low. Here, we use data from 289 residents of an agricultural Tibetan village to assess whether individuals are more inclined to establish supportive relationships with religious individuals in general and to investigate the gender disparities in the relationship between religiosity and personal network characteristics. Our results reveal that participation in religious rituals contributes to the overall development of social support networks. The benefits to personal networks, however, seem to be contingent upon gender. For resource-intensive, infrequent religious rituals such as distant pilgrimages, males seem to benefit slightly more in terms of elevated in-degree values in their personal networks, despite similar levels of investment as females. In contrast, for daily, low-cost religious practices requiring ongoing participation, both genders obtain similar increases in in-degree values through regular engagement. It becomes more challenging for women to increase their status in communities when the effort invested in religious rituals yields smaller rewards compared with the same effort by men, contributing to ongoing gender inequality. These findings highlight the importance of examining the particular characteristics of religious rituals and the gender disparities in the associated rewards.

Understanding the dynamics of inter-group cooperation in human adaptation has been the subject of recent empirical and theoretical studies in evolutionary anthropology, beginning to fill gaps in our knowledge of how interactions across political, economic and social domains can – and often do – lead to stable, large-scale cooperation. Here we investigate dyadic intergroup cooperation in shotgun hunting in the Republic of the Congo. In the Congo Basin, inter-group cooperation between foragers and farmers is at the centre of an exchange system maintained by traditional norms and institutions such as fictive kinship. Here, we focused on what factors predict cooperative shotgun hunting exchanges between BaYaka and Yambe. We conducted structured interviews with 48 BaYaka hunters and 18 Yambe men who organise hunts in a village along the Motaba River. We used Bayesian multilevel regression models to investigate the influence of Yambe and BaYaka attributes on probability of dyadic cooperation. We found that BaYaka men's reputations as skilled hunters and their family size each predicted cooperation in shotgun hunting, whereas there was no effect of Yambe attributes (status, wealth, family size). We discuss the results in terms of evolutionary models of men as hunters and inter-group cooperation, as well as biodiversity conservation implications.

Although still prevalent in many human societies, the practice of cousin marriage has precipitously declined in populations undergoing rapid demographic and socioeconomic change. However, it is still unclear whether changes in the structure of the marriage pool or changes in the fitness-relevant consequences of cousin marriage more strongly influence the frequency of cousin marriage. Here, we use genealogical data collected by the Tsimane Health and Life History Project to show that there is a small but measurable decline in the frequency of first cross-cousin marriage since the mid-twentieth century. Such changes are linked to concomitant changes in the pool of potential spouses in recent decades. We find only very modest differences in fitness-relevant demographic measures between first cousin and non-cousin marriages. These differences have been diminishing as the Tsimane have become more market integrated. The factors that influence preferences for cousin marriage appear to be less prevalent now than in the past, but cultural inertia might slow the pace of change in marriage norms. Overall, our findings suggest that cultural changes in marriage practices reflect underlying societal changes that shape the pool of potential spouses.

Knowledge and behaviour are transmitted from one individual to another through social learning and eventually disseminated across the population. People often learn useful behaviours socially through selective bias rather than random selection of targets. Prestige bias, or the tendency to selectively imitate prestigious individuals, has been considered an important factor in influencing human behaviour. Although its importance in human society and culture has been recognised, the formulation of prestige bias is less developed than that of other social learning biases. To examine the effects of prestige bias on cultural evolution theoretically, it is imperative to formulate prestige and investigate its basic properties. We reviewed two definitions: one based on first-order cues, such as the demonstrator's appearance and job title, and the other based on second-order cues, such as people's behaviour towards the demonstrator (e.g. people increasingly pay attention to prestigious individuals). This study builds a computational model of prestige bias based on these two definitions and compares the cultural evolutionary dynamics they generate. Our models demonstrate the importance of distinguishing between the two types of formalisation, because they can have different influences on cultural evolution.

Globally, human house types are diverse, varying in shape, size, roof type, building materials, arrangement, decoration and many other features. Here we offer the first rigorous, global evaluation of the factors that influence the construction of traditional (vernacular) houses. We apply macroecological approaches to analyse data describing house features from 1900 to 1950 across 1000 societies. Geographic, social and linguistic descriptors for each society were used to test the extent to which key architectural features may be explained by the biophysical environment, social traits, house features of neighbouring societies or cultural history. We find strong evidence that some aspects of the climate shape house architecture, including floor height, wall material and roof shape. Other features, particularly ground plan, appear to also be influenced by social attributes of societies, such as whether a society is nomadic, polygynous or politically complex. Additional variation in all house features was predicted both by the practices of neighouring societies and by a society's language family. Collectively, the findings from our analyses suggest those conditions under which traditional houses offer solutions to architects seeking to reimagine houses in light of warmer, wetter or more variable climates.