Discovery of ancient structures in Samoa may offer clues to origins of inequality

A new study by archaeologists at the University of Auckland may have revealed the origins of hierarchical society in Samoa and throughout Polynesia.

New research reveals that the recent discovery of ancient rock walls, towering mounds and deep trenches in the dense forests of the Valeva Valley on the island of Upolu in Samoa offers important insights into the roots of land ownership and social stratification in Polynesian culture.

Led by Associate Professor Ethan Cochran from Waipapa Taumata Rau, University of Auckland, the study makes new links between the dramatic rise in population in Samoa, richer agricultural land in certain areas, and the beginnings of land demarcation and the social status associated with it.

These connections were of great interest to ordinary Samoans, Cochrane says.

“They have the most intimate knowledge of their land, and are now able to compare ancient political and village boundaries revealed through archaeology with modern ones, and those known through oral tradition, and see where the differences lie.”

The team’s fieldwork in Samoa focused on LiDAR (Light Detection and Ranging), a mapping technique that uses light in the form of a pulsed laser to measure variable distances to the ground, from which a topographic map is created.

The crucial thing here, Cochrane says, is that lidar, when flown from an aircraft, penetrates tiny gaps in dense foliage to reveal what would otherwise be covered by forest cover.

“This technology has been used for the last 15 to 20 years all over the Pacific, and the great thing it can do is remove even dense jungle environments. This is one of the first times it has been used in Samoa, so all these amazing rock walls, platforms and mounds, which are between 600 and 900 years old, can be seen in great detail.”

Field Challenges and Architectural Discoveries

Traversing through dense jungle, in heavy rain and blazing sun, and being attacked by mosquitoes at every turn, much like Indiana Jones archaeology, may not be for everyone, Cochrane says, but the rewards, in this case, make any inconvenience worth it.

“Up close, these structures are amazing pieces of architecture. Some were family dwellings made of stone and mud, much like you see in some Samoan villages today, others were civic or ceremonial construction projects. Some are so-called ‘star mounds’, which can be up to two metres high, and were probably used to stand on to hunt pigeons, a sport that was primarily practiced.”

The study, conducted in partnership with the National University of Samoa and with permission from local villages, is not the first to find these structures, but it is the first to link the timing and reasons for their construction to what he calls the “collective action problem,” he says.

Associate Professor Ethan Cochran in the field, Valeva Valley, Upolu Island, Samoa. Photo: University of Auckland

“We found that this construction of things – kilometre-long rock walls restricting access to land, irrigation ditches to create a productive wetland agricultural system – is a response to the massive population increase in Samoa that we know occurred around that time. [from 900 years ago]”.”

“In this case, sharing resources with everyone means less for everyone, so the problem becomes, ‘When does it become beneficial for individuals to contribute to collective defense at the expense of themselves and to exclude other groups from accessing the group’s resources?’”

He says that after such a rapid increase in population in the valley, people did just that: they fenced off areas from others to maintain their access to a valuable resource.

“In this case, the oldest massive rock walls are located near the most fertile lands in the western and northern regions of the valley, which we know to be true from analysis of soil samples in the area of ​​these structures.”

Cochrane says it is possible that the entire Samoan leadership system, which we see in Polynesian society in general, was based on who had access to land in those early times and who did not, and this may also have been the cause of similar changes in early societies around the world.

“We have often wondered why hierarchical societies have emerged all over the planet over thousands of years, while most human societies, about 20,000 years ago, were more egalitarian and there were fewer positions of status and power among hunter-gatherers.

“But now we live at the other extreme, where in many, if not all, societies there is a social status, a hierarchy, a level where some people have unimaginable power and others have none.”

Reference: “Collective Action Problems Led to Cultural Transformation in Samoa 800 Years Ago” by Ethan E. Cochran, Seth Quintus, Matthew Prebble, Taiao Omoa Oselaphi Mateiu Tautunu, Dolly Otofuga, Mana Laumia, Alexandra Koenen, Paul Augustinus, and Noa Kikuwa Lincoln, June 20, 2024, Plus one.
DOI: 10.1371/journal.pone.0304850