New research reconstructs ancient history of Island Southeast Asia

(PhysOrg.com) -- An article in this month's Current Anthropology challenges the controversial idea that Island Southeast Asia was settled 5,000 years ago by a migration of farmers from Taiwan.

The article, by Mark Donohue of the Australian National University and Tim Denham of Monash University (Melbourne, Australia), also questions the broader idea that farming technology and language spread together in many parts of the world as a “cultural package.”

Scholars have debated for years about the history of Island Southeast Asia—the present-day countries of the Philippines, Indonesia and Malaysia. The most prominent theory about the region’s history is the “out of Taiwan” model. According to the model, people from Taiwan migrated south into the region about 5,000 years ago. Advanced farming technology enabled the migrants to displace indigenous hunter-gatherers, and establish their culture and language as the dominant one in the region. Linguistic evidence seems to support that version of events. All of the languages spoken in the region—called the Austronesian languages—can be traced back to a Taiwanese origin.

Influential scholars, including Guns, Germs and Steel author Jared Diamond, believe that the “out of Taiwan” model is a prime example of how prehistoric farming cultures tended to expand their territories, bringing their language and other cultural traditions with them. Advocates of the model believe similar scenarios explain language patterns in areas of Europe and Sub-Saharan Africa.

But Donohue and Denham present a very different history of Island Southeast Asia.

“Genes, languages and material culture—including agriculture—did not all spread together through migration,” Donohue said. Instead, the region was “home to a mosaic of maritime networks of social interaction prior to the spread of the Austronesian languages.”

The latest genetic studies show no evidence of a large-scale Taiwanese migration, the Donohue and Denham contend. “Although some of the genetic variation among human populations in [the region] can be attributed to Taiwanese influence, the proportion does not by any means represent the wholesale replacement or absorption of preexisting populations,” they write.

In terms of agriculture, Donohue and Denham show that many of the domesticated plants and animals common in the region appear to have arrived before any Taiwanese influence—and from multiple sources. Chickens and pigs most likely came from mainland Southeast Asia, and bananas and sugarcane from New Guinea. Such evidence challenges the notion that the region owes its agricultural history solely to Taiwanese migrants.

A detailed look at the linguistics of the region also casts doubt on the explanatory power of the “out of Taiwan” model, according to Donohue and Denham. Languages change over time and as populations move around. If the Austronesian languages came to the region through a southward Taiwanese migration of peoples, one would expect that the languages spoken in the northern part of the region would be more similar to the original source language than the ones spoken in the southern part, which matches the dispersal of some archaeological markers. But that is not the linguistic pattern in Island Southeast Asia. According to Donohue and Denham, there is no linguistic evidence for an orderly north-to-south dispersal.

Irregular patterns in the vocabulary and grammar and other linguistic anomalies throughout the region call into question the idea that the language came to the region through mass migration. Rather, Donohue and Denham suggest that the profile of the Austronesian languages in Island Southeast Asia is “consistent with the mechanisms of language shift and abnormal transmission.”

Taken as a whole, the evidence from genetics, archaeology and linguistics calls into the question the idea that agriculture and language spread together, Donohue and Denham conclude.

“The demonstration that farming and language did not reach Island Southeast Asia together has implications for other places where that idea has been applied, including Europe and sub-Saharan Africa,” Denham said.