PhysOrg reports on archaeologists studying “bone modification,” a custom that seems to have been practiced among the first city-dwellers in southern China, who set up a kind of standardized workshop for sculpting human remains:
The majority of worked bones could be classified as skull cups, mask-like facial skulls, small plate-shaped skull fragments, skulls with posterior perforations, mandibles with flattened mandibular bases, and limb bones with working traces.
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In many cultures, worked human bones are the result of an intricate relationship between the worker and the worked, associated with kinship and conflict.
However, the lack of signs of violence and cutmarks indicate these worked bones were unlikely to have been obtained during episodes of violence, possibly linked with war or enmity.
Additionally, the presence of many of these bones in Zhongjiagang, which served as Liangzhu’s workshop, may suggest that these bones were the result of a standardized production process.
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Interestingly, the majority of these worked bones appear unfinished, around 80%, and were apparently deliberately discarded in the canals of the moats.
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However, with the advent of the much larger and less closely known Liangzhu culture, social bonds appear to have undergone a fundamental transformation. Dr. [Junmei] Sawada and his colleagues propose that urbanization may have altered how the living viewed the dead, particularly those outside their immediate kinship networks.
You can read more of the memento mori research here, in Scientific Reports.