In this chapter, Diamond lists three factors that determine how much technology a given area will have. He says that the differences that we observe between the various continents are caused by these factors. The factors are:
- Onset of food production. The sooner a place got agriculture, the more developed its technology will be.
- Barriers to diffusion. Much technology is acquired by borrowing from other cultures. The easier it is for technology to diffuse from place to place in a given area, the more technology societies in that area will have.
- Human population size. The more people there are, the more potential inventors there are.
Technological development differed from place to place because of these factors.