Photos: Prehistoric Rock Art Hints at Elite Class on Kisar

Effects of trade

Indonesian rock paintings

(Image credit: Sue O'Connor/ANU)

O’Connor thinks human society on these islands became more hierarchical after trade was established with other regions about 3000 years ago.

She says that Bronze Age prestige items, such as Dong Son drums, may have been traded for rare spices such as nutmeg, mace and cloves, which were once found only on these islands.

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Tom Metcalfe is a freelance journalist and regular Live Science contributor who is based in London in the United Kingdom. Tom writes mainly about science, space, archaeology, the Earth and the oceans. He has also written for the BBC, NBC News, National Geographic, Scientific American, Air & Space, and many others.