The answer to this can be found beginning at the bottom of p. 247 in the paperback edition of the book.
Diamond says that adopting technologies from other societies is a very important way for a society to become more advanced. He wants to understand why some outside technologies do not get adopted. He wants to show that it is wrong to say that some races are simply more open to technology than others. Instead, he lists four influences on whether a society will accept a particular outside technology. They are:
- How much better the new technology is. If an invention is way more useful than what you already have, you are more likely to adopt it.
- Social value or prestige. Diamond uses the example of the Japanese writing system here. He says that Japan continues to use pictograms instead of just using the syllabary that it already has simply because the kanji pictograms have prestige attached to them.
- Compatibility with vested interests. If people who have power and influence are already tied to a given technology, new technologies will not be allowed to replace it. He cites how British governments invested heavily in gas lighting and therefore were slow to replace it with electrical lighting when that was invented.
- How obvious the advantages are. This is closely related to the first factor. If it is easy to see that the new technology is better than what you have, you will be more likely to adopt that technology.
These factors, Diamond argues, determine whether a society will adopt a certain technology.