Why did researchers reject the theory that Polynesians came from South America?

Researchers have rejected the theory that Polynesians originated in South America because it lacks scientific credibility and is contradicted by extensive archaeological, linguistic, and ethnological evidence.1

While figures such as Thor Heyerdahl attempted to demonstrate the possibility of such migrations—most famously through his Kon-Tiki expedition—modern scholarship consistently supports the hypothesis that Oceania was settled by a succession of migrants from Southeast Asia.12

Linguistic and archaeological data indicate that Austronesian speakers moved from Taiwan through the Philippines and Indonesia, eventually reaching the western Pacific by approximately 2000 BCE. This dispersal is closely linked to the Lapita culture, characterized by distinctive pottery and sophisticated maritime technology. Although there is evidence of prehistoric contact between Polynesians and the American continent—most notably the presence of the sweet potato in Oceania—this is considered a minor interaction rather than evidence of a South American origin for the Polynesian people.3451