It has long seemed like a tidy story about human ingenuity: After people started farming about 10,000 years ago and were faced with the challenge of cooking plants and grains, pottery was invented.
But that explanation has been fraying for years, and now an international team that includes a Harvard University anthropologist and Boston University scientists has pushed back the timeline even further, with evidence of pot shards from a cave in eastern China that date to 10 millennia before agriculture began.
"We always think hunters and gatherers go with bows and arrows and hunt animals, collect food," said Ofer Bar-Yosef, 75, a professor of anthropology at Harvard who led the new work published in the journal Science. "They also make some pottery."
The team revisited Xianrendong Cave, a prehistoric site about 60 miles south of the Yangtze River that over the decades had yielded an array of artifacts, including tools made of stone, bone, and shells; animal bones; and fragments of pottery. The scientists reopened the trench, excavated blocks of sediment, and analyzed bone fragments and layers of sediment to get the precise age of layers where pot shards had been discovered earlier. They used radiocarbon dating of large bone fragments at Peking University.
Sediment up close
Then, to make sure they were getting accurate measurements and that the sediments hadn't shifted, researchers examined slices of sediment up close, to check that the layers had remained stable since they were first deposited. The technique was so sensitive that they reported evidence of worms tunneling through the sediment. They found that the shards were 19,000 to 20,000 years old -- several thousand years older than the previous oldest-known pot shards.
That find challenges traditional explanations of the emergence of a sophisticated technology that would have transformed human nutrition and social interaction, said Gideon Shelach, a professor in the department of East Asian Studies at Hebrew University. "Pottery was extensively used for a lot of purposes. Cooking, serving, but also for rituals, prestige objects; it continues to be used for a long time -- until today -- so it's one of the most enduring technologies and the most widespread technologies in all parts of the world," he said. "It's a very, very fundamental technology of humankind."
The evidence that pottery is older than previously believed deepens questions about what the pots were used for and how their use may have evolved and become more widespread as other developments, including farming and staying in one place, began to transform human life.
Vessel as social player
Bar-Yosef said he hopes to be able to do further analysis to see if anything can be learned about what was stored or cooked inside the small pots.
Researchers observed evidence of burning on the outside of the fragments, suggesting they may have been used in cooking. Because the pottery dates to a period when the glaciers were large and the environment might have been harsh, the scientists proposed the pots could have proved useful in making maximum use of resources. For example, they could have been used to cook crushed bones and extract precious nutrients.
Another possibility, Shelach suggests, is that people were living closer together and the vessels played a social role, enabling feasting rituals, or the brewing of alcoholic beverages.