For the most part we see what we expect to see.

Scholars have long assumed the Spaniards first introduced chickens to the New World along with horses, pigs, and cattle. But now radiocarbon dating and DNA analysis of a chicken bone excavated from a site in Chile suggest Polynesians in oceangoing canoes brought chickens to the west coast of South America well before Europe's "Age of Discovery." . . .

In 1532, Spanish conquistador Francisco Pizarro recorded the presence of chickens in Peru, where the Inca used them in religious ceremonies. "That suggests chickens had already been there for a while," says Storey. "It's possible there are stylized chickens in the iconography that we have not recognized because we did not know they were there.

A great deal of scholarship seems like this to me. The more we know the less we see . . . until someone manages to be confronted by something difficult to deny, and so comes to doubt known things that ain't so.