Early Times
The Evolutionary Role of Dance: Group Bonding But Not Prosocial Altruism
Bronwyn Tarr & Robin Dunbar
Evolutionary Behavioral Sciences, forthcoming
Abstract:
That synchronized activities like dancing or marching positively influence social bonding has been widely demonstrated for both dyads and small groups. However, previous studies of other social bonding behaviors (laughter and behavioral synchrony) have suggested that these prosocial effects do not extend to altruistic actions (generosity in economic games), implying that social bonding and prosociality may be underpinned by different psychological processes. Here, we ask whether dancing to music in a naturalistic (i.e., nonlaboratory) context makes people feel more socially bonded and/or more altruistic (in an economic game) compared to another real-world, exertive activity (group-based gym circuit training sessions). We found that the type of activity did not affect measures of either social bonding or generosity. However, confirming the earlier findings for laughter, we show that while any form of exertive activity elevates the sense of group bonding (entitativity), it has no effect either on ratings of willingness to act prosocially toward another individual, or on actually acting generously toward them in an economic game. Taken together, these results suggest that altruism, cooperation, and other forms of prosociality may be the outcome of creating bonded relationships and groups, rather than their cause.
A double-pointed wooden throwing stick from Schöningen, Germany: Results and new insights from a multianalytical study
Annemieke Milks et al.
PLoS ONE, July 2023
Abstract:
The site of Schöningen (Germany), dated to ca. 300,000 years ago, yielded the earliest large-scale record of humanly-made wooden tools. These include wooden spears and shorter double-pointed sticks, discovered in association with herbivores that were hunted and butchered along a lakeshore. Wooden tools have not been systematically analysed to the same standard as other Palaeolithic technologies, such as lithic or bone tools. Our multianalytical study includes micro-CT scanning, 3-dimensional microscopy, and Fourier transform infrared spectroscopy, supporting a systematic technological and taphonomic analysis, thus setting a new standard for wooden tool analysis. In illustrating the biography of one of Schöningen’s double-pointed sticks, we demonstrate new human behaviours for this time period, including sophisticated woodworking techniques. The hominins selected a spruce branch which they then debarked and shaped into an aerodynamic and ergonomic tool. They likely seasoned the wood to avoid cracking and warping. After a long period of use, it was probably lost while hunting, and was then rapidly buried in mud. Taphonomic alterations include damage from trampling, fungal attack, root damage and compression. Through our detailed analysis we show that Middle Pleistocene humans had a rich awareness of raw material properties, and possessed sophisticated woodworking skills. Alongside new detailed morphometrics of the object, an ethnographic review supports a primary function as a throwing stick for hunting, indicating potential hunting strategies and social contexts including for communal hunts involving children. The Schöningen throwing sticks may have been used to strategically disadvantage larger ungulates, potentially from distances of up to 30 metres. They also demonstrate that the hominins were technologically capable of capturing smaller fast prey and avian fauna, a behaviour evidenced at contemporaneous Middle Pleistocene archaeological sites.
Evidence of artefacts made of giant sloth bones in central Brazil around the last glacial maximum
Thais Pansani et al.
Proceedings of the Royal Society: Biological Sciences, 12 July 2023
Abstract:
The peopling of the Americas and human interaction with the Pleistocene megafauna in South America remain hotly debated. The Santa Elina rock shelter in Central Brazil shows evidence of successive human settlements from around the last glacial maximum (LGM) to the Early Holocene. Two Pleistocene archaeological layers include rich lithic industry associated with remains of the extinct giant ground sloth Glossotherium phoenesis. The remains include thousands of osteoderms (i.e. dermal bones), three of which were human-modified. In this study, we perform a traceological analysis of these artefacts by optical microscopy, non-destructive scanning electron microscopy, UV/visible photoluminescence and synchrotron-based microtomography. We also describe the spatial association between the giant sloth bone remains and stone tools and provide a Bayesian age model that confirms the timing of this association in two time horizons of the Pleistocene in Santa Elina. The conclusion from our traceological study is that the three giant sloth osteoderms were intentionally modified into artefacts before fossilization of the bones. This provides additional evidence for the contemporaneity of humans and megafauna, and for the human manufacturing of personal artefacts on bone remains of ground sloths, around the LGM in Central Brazil.
Early contact between late farming and pastoralist societies in southeastern Europe
Sandra Penske et al.
Nature, forthcoming
Abstract:
Archaeogenetic studies have described two main genetic turnover events in prehistoric western Eurasia: one associated with the spread of farming and a sedentary lifestyle starting around 7000–6000 BC and a second with the expansion of pastoralist groups from the Eurasian steppes starting around 3300 BC. The period between these events saw new economies emerging on the basis of key innovations, including metallurgy, wheel and wagon and horse domestication. However, what happened between the demise of the Copper Age settlements around 4250 BC and the expansion of pastoralists remains poorly understood. To address this question, we analysed genome-wide data from 135 ancient individuals from the contact zone between southeastern Europe and the northwestern Black Sea region spanning this critical time period. While we observe genetic continuity between Neolithic and Copper Age groups from major sites in the same region, from around 4500 BC on, groups from the northwestern Black Sea region carried varying amounts of mixed ancestries derived from Copper Age groups and those from the forest/steppe zones, indicating genetic and cultural contact over a period of around 1,000 years earlier than anticipated. We propose that the transfer of critical innovations between farmers and transitional foragers/herders from different ecogeographic zones during this early contact was integral to the formation, rise and expansion of pastoralist groups around 3300 BC.
Longstanding behavioural stability in West Africa extends to the Middle Pleistocene at Bargny, coastal Senegal
Khady Niang et al.
Nature Ecology & Evolution, July 2023, Pages 1141–1151
Abstract:
Middle Stone Age (MSA) technologies first appear in the archaeological records of northern, eastern and southern Africa during the Middle Pleistocene epoch. The absence of MSA sites from West Africa limits evaluation of shared behaviours across the continent during the late Middle Pleistocene and the diversity of subsequent regionalized trajectories. Here we present evidence for the late Middle Pleistocene MSA occupation of the West African littoral at Bargny, Senegal, dating to 150 thousand years ago. Palaeoecological evidence suggests that Bargny was a hydrological refugium during the MSA occupation, supporting estuarine conditions during Middle Pleistocene arid phases. The stone tool technology at Bargny presents characteristics widely shared across Africa in the late Middle Pleistocene but which remain uniquely stable in West Africa to the onset of the Holocene. We explore how the persistent habitability of West African environments, including mangroves, contributes to distinctly West African trajectories of behavioural stability.