New clues to New Guinea’s past

Artefacts uncovered in the highlands of what is now Papua New Guinea (PNG) reveal a shift in human behaviour between 5050 and 4200 years ago in response to the widespread emergence of agriculture, ushering in a regional era similar to the Neolithic in Eurasia.

While scientists have known that wetland agriculture originated in the highlands between 8000 and 4000 years ago, until now there has been little evidence for corresponding social changes like those that occurred in other parts of the world.

The new artefacts were excavated at the recently discovered Waim archaeological site in the Jimi Valley.

Their location and pattern suggest a fixed domestic space and symbolic cultural practices, hinting that the region began to independently develop hallmarks of the Neolithic about 1000 years before Lapita farmers from Southeast Asia arrived in New Guinea.

“What is truly exciting is that this was the first time these artefacts have been found in the ground, which has now allowed us to determine their age with radiocarbon dating,” says lead researcher Ben Shaw, from Australia’s UNSW Sydney.

Shaw and colleagues from Australia, New Zealand, PNG and the US say they were astounded by the sheer bulk and variety of tools that turned up in the one place at Waim.

They found very finely carved pestles used for the grinding of food, stone axes and adzes, as well as carved figurines.

One large fragment of carved stone depicting the brow ridge of a human or animal face dated at 5050 years old is the earliest evidence of a carved expression of body form in Oceania.

After examining them under the microscope, co-author Judith Field identified microfossils – or evidence of plant residue – on the pestles demonstrating they had been used to process some of the wetland crops native to New Guinea.

“It was very exciting for us to find these microfossils on the pestles,” Field says. “It is probably one of the most direct links that you can draw to the influence of agriculture upon human behaviour at this time.”

Shaw says the dig also was interesting for what the unearthed relics reveal about the antiquity of some of the technology still being used today in New Guinea. A grooved volcanic stone was found with ochre on it, suggesting that 5000 years ago humans were already using it to paint, stain and decorate.

The researchers present their findings in a paper in the journal Science Advances.