Yali's question was Jared Diamond's inspiration for writing Guns, Germs, and Steel. Diamond, as an anthropologist, had been working in Papua New Guinea, studying members of a culture who were still in the Stone Age, having invented only stone tools, rather than more complex technologies. As Diamond became acquainted with members of these cultures as individuals, he recognized that as individuals they were as smart, hard-working, creative, and talented as the members of western civilization. This prompted him to wonder about the origins of the differences between Papua New Guinea culture and western culture, and why western cultures seemed so much more successful on a material level. What crystallized the issue for Diamond was when his friend Yali asked him:
[Yali's Question:] “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?”
The term "cargo" in this context means a variety of goods from packaged flour to metal tools to cell phones. Diamond's book responds to this question by locating the difference not in the nature of the people of the different cultures but in geography and environment.