Past Thinking
Individual Differences in Great Ape Cognition Across Time and Domains: Stability, Structure, and Predictability
Manuel Bohn et al.
Psychological Science, forthcoming
Abstract:
Understanding variation in cognitive abilities is critical to understanding both the evolution and development of cognition. In this study, we examined the stability, structure, and predictability of individual differences in cognitive abilities in great apes across a broad range of domains, including social cognition, reasoning about quantities, executive function, and inferential reasoning. We administered six tasks to 48 individuals from four species, spanning 10 sessions over 1.5 years. Task performance was most strongly predicted by stable, individual-specific characteristics rather than transient or group-level variables. Using additional data from the same individuals in other tasks, we found substantial positive correlations between nonsocial tasks. In contrast, tasks measuring social cognition were not correlated either with each other or with nonsocial measures. Future studies should work toward mechanistic models of great apes’ cognitive processes to build an understanding of the evolution of cognition based on process-level commonalities across species.
Integrating cannabis into the prehistoric crop assemblage: Phytolith evidence from Shandong, Northern China (4500-3400 BP)
Xu Liu et al.
Journal of Archaeological Science, May 2026
Abstract:
Cannabis sativa has probably been domesticated and utilized in Eurasia during the Early Neolithic (approximately 12,000 BP), undergoing strong divergent selection for increased fiber or drug production by c. 4000 BP, with its spread to Western Eurasia during the Bronze Age (3800–2200 BP). However, the limited preservation of organic remains, such as seeds, pollen, and fiber products, has impeded our understanding of when cannabis became an integral part of crop assemblages. This study presents the first identification of cannabis phytoliths from the Late Neolithic (4500–3800 BP) to Early Bronze Age (3800–3400 BP) at the Beitaishang and Qianzhongzitou sites in Shandong, northern China. The cannabis phytoliths in archaeological samples are predominantly monomeric, a characteristic influenced not only by the intrinsic properties of the cannabis phytoliths but also by factors such as processing, preservation, and experimental procedures, as shown by comparisons with modern cannabis samples. The ubiquity of cannabis phytoliths at both sites exceeds 50%, and their co-occurrence with staple crops such as foxtail millet, broomcorn millet, and rice reaches 84-100%. These phytoliths are primarily found in domestic contexts, including ash pits and houses. These findings suggest that cannabis had been systematically integrated into the local agricultural economy, becoming a key component of the core crop assemblage in northern China by at least the Late Neolithic. This study highlights how phytolith analysis can effectively overcome the preservation biases of organic remains, offering a new avenue for understanding the role of cannabis in the subsistence system of prehistoric northern China and its spread and utilization across prehistoric East Asia.
The evolutionary history and unique genetic diversity of Indigenous Americans
Marcos Araújo Castro e Silva et al.
Nature, forthcoming
Abstract:
Indigenous peoples of America represent the last principal expansion of humans across the globe, yet their genetic history remains one of the least explored. Although these populations have inhabited the continent for thousands of years, their evolutionary history remains largely unresolved, owing to the limited availability of genomic data. Here we present data on 128 high-coverage Indigenous American genomes and show they harbour extensive and previously uncharacterized genetic diversity, reflecting at least three dispersals into South America, followed by regional differentiation and long-term continuity. We identified widespread natural selection signals in genes associated with immunity, metabolism, reproduction and development, which were shaped by adaptation to diverse environmental conditions. Notably, several genomic regions exhibit a remarkable allele sharing with Australasian populations, probably originating from an ancient admixture event and partly maintained by selection for more than 10,000 years. We also detected distinct contributions from archaic humans with adaptive introgression affecting key biological functions. The limited overlap between the regions of Australasian affinity and archaic ancestry indicates independent evolutionary origins of these signals. These findings challenge simplified models of continental settlements and show a more dynamic and complex evolutionary history for the Indigenous peoples in America.
The representation of cave lions in Paleolithic art: Temporal differences and anatomical accuracy
Chi-Shan Tsai et al.
Journal of Archaeological Science: Reports, May 2026
Abstract:
This study investigates the representation of cave lions (Panthera [leo] spelaea) in Upper Paleolithic art in France, dated between 40,000 and 12,000 years ago. Using an interdisciplinary approach, we aimed to identify depictions of cave lions among feline figures and assess the level of anatomical accuracy and familiarity prehistoric humans had with this extinct species. Our methodology combined a comprehensive survey of Paleolithic images (including cave art and portable objects), the reconstruction of a life-sized cave lion model, analyses of body proportions, and multivariate analyses of variance (MANOVA). The results reveal that most feline representations correspond closely to the proportions of the cave lion, particularly in terms of head dimensions, which remain consistent across pre-Magdalenian and Magdalenian periods. In contrast, body proportions show temporal variation, suggesting potential evolutionary changes in the species, shifts in artistic representations, cultural transformations in iconography, or stylistic preferences. Our findings highlight both the detailed anatomical knowledge and the complex symbolic and aesthetic choices of Paleolithic artists in their representations of large carnivores.
Custom is lord of all − The Bronze Age spread of the cremation custom in Northern Bronze Age by using strontium isotopes
Stefanie Schaefer-Di Maida, Corina Knipper & Jutta Kneisel
Journal of Archaeological Science: Reports, May 2026
Abstract:
With the aim of reconstructing the spread of cremation burials around 1300 BCE, cremation burials from Schleswig-Holstein were selected for the study. The selection was made on the basis of previous research, e.g., whether the burials were of early date and thus were among the first cremations in Schleswig-Holstein. The graves came from Albersdorf, Bornhöved, Grevenkrug, Leezen, Mang de Bargen and Nützen. The question arose as to the mobility of these people, i.e., whether they were local or non-local. The burnt bone material was sampled and analysed for strontium isotope composition. Information on the geological conditions, which is crucial for the interpretation of the results, was also compiled for Schleswig-Holstein and compared with existing research and environmental samples from Jutland and Funen, as well as samples from Schleswig (Haithabu). More data is of course needed for a reliable assessment, but these initial investigations show that the early cremations were probably non-local. Furthermore, previously published osteological analyses revealed that these individuals were often children, so it can be assumed that children played an important role in the spread of the new burial type.