Comment by divbzero

That's not Heyerdahl's diffusion model. From https://en.wikipedia.org/wiki/Thor_Heyerdahl

> The expedition was supposed to demonstrate that the legendary sun-worshiping red-haired, bearded, and white-skinned "Tiki people" from South America drifted and colonized Polynesia first, before actual Polynesian peoples. His hyperdiffusionist ideas on ancient cultures had been widely rejected by the scientific community, even before the expedition ....

> Heyerdahl's hypothesis was part of early Eurocentric hyperdiffusionism and the westerner disbelief that (non-white) "stone-age" peoples with "no math" could colonize islands separated by vast distances of ocean water, even against prevailing winds and currents. He rejected the highly skilled voyaging and navigating traditions of the Austronesian peoples and instead argued that Polynesia was settled from boats following the wind and currents for navigation from South America. ...

The genetic evidence does not support his theory.

Nor is it right to attribute the idea of a possible connection to Heyerdahl. Nordenskiöld wrote about "'Oceanian' Cultural Elements in South America" in 1931, https://archive.org/details/09-comparative-ethnographical-st...

> As is well known, we find in South America quite a number of culture elements of which parallels are found in Oceania.1 These we may call ’’Oceanian’’, although this certainly does not imply any proof that they have been imported into America from Oceania. These “Oceanian’’ culture elements may derive their origin from the crew of some weather-driven vessel, because the possibility of such having landed upon the coasts of America is not entirely to be disregarded, as Friederici has fairly convincingly shown.

> [p24]... Friederici has pointed out that there is much which speaks for the theory of weather-driven Oceanian vessels having reached America but nothing of their returning whence they came, or of Indians sailing westward and reaching any Oceanic island. It is important to note that all islands off the South American coast that cannot be seen from the mainland, such as the Galapagos, Juan Fernandez, etc., at the time of the discovery of America were uninhabited and, judging from everything, always had been so.

(I think the Friederici reference is "Zu den vorkolumbischen Verbindungen der Südsee-Völker mit Amerika" - "Regarding the pre-Columbian connections of the South Seas with America", 1929. Heyerdahl was born in 1914, so about 15 years old.)

As I recall, the prevailing hypothesis was that any contact came likely from the Pacific. Heyerdahl didn't believe that was possible, and it must have been the other way. People argued that South Americans didn't have the sailing ability to reach Polynesia. Heyerdahl demonstrated that opposing argument was incorrect, by doing it. That doesn't mean it must have happened.

So, no, Heyerdahl's hypothesis is completely wrong, and the new evidence we have more strongly support older hypotheses by others, which Heyerdahl disagreed with.