In Yali's Question, Errington and Gewertz think that Diamond misunderstood what New Guineans really wanted from Westerners when he interpreted the meaning of Yali's question. In Guns, Germs, and Steel, what did Diamond think Yali's question about cargo meant, and what do Errington and Gewertz think that Yali really meant?
Diamond says that he was inspired to write Guns, Germs, and Steel by a question that was asked to him by Yali, a New Guinean leader. On p. 14 of the paperback edition of the book, Diamond tells us that Yali asked him
Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own?
To Diamond, this is a question about why some societies became rich and powerful while others did not. He believes that Yali is asking why the white people who came to New Guinea were able to have a society that could have so many material goods while the people of New Guinea were not able to do so. He writes Guns, Germs, and Steel as an attempt to answer that question.
Errington and Gewertz, by contrast, understand Yali in a different way. They say that Yali was not asking about material goods. They say, instead, that he was asking why white people treated New Guineans so badly. On p. 25 of their book, they say that
…Diamond does not understand that Yali really was asking less about cargo per se than about colonial relationships between white and black people…
Errington and Gewertz, then, think that Yali was asking about the way Europeans behaved while Diamond thinks he was asking about the goods that they possessed.