Why Did Human History Unfold Differently On Different Continents For the Last 13,000 Years?

In Jared Diamond's article, "Why Did Human History Unfold Differently On Different Continents For the Last 13,000 Years?," he examines why societies developed differently on various continents. He attempts to pinpoint the cause of faster developing societies. By doing this he is able to explain why Eurasia was able to conquer the rest of the world and not the other way around. Diamond identifies environmental factors as the cause to the disparity in the development of different regions, noting that biological factors, such as average IQ, are not related to this difference.

Diamond identifies domesticable plants and animals, an east/west land orientation, and the ability to interact with other societies as the most important determinants of a society's success.
Societies with domesticable plants and animals yield more calories per acre allowing for greater population density and movement away from hunter/gatherer society. The existence of surpluses and storage due to agriculture allows for the development of a stratified society with governing elites. Domesticable plants and animals also allow for the accelerated development of technology because it is not necessary for all people to raise their own food so some can devote their time to creating "metallurgy, writing, swords and guns." The domesticable plants and animals also allowed for the spread of germs and disease which wiped out hunter/gatherer societies.

An east/west land orientation allows for the spread of these domesticable plant and animal species because of the same day-lengh and climate. In north/south oriented continents, plants and animals that are domesticated in on region cannot be easily spread to other regions without adaptation. Eurasia being oriented on an east/west axis allowed for the fast spread of domesticated plants and animals. Africa and the Americas are oriented on a north/south axis making the spread of these species difficult.

Diamond also indicates a society's ability to interact and share technologies and developments with other societies allows for faster development. Societies sometimes experience fads where they discontinue beneficial practices or start a non beneficial practice. When these societies are in contact with others that did not experience this fad they are able to redevelop in a positive way. When a society is isolated they do not have other societies to share and gain technologies from, they do not develop as as quickly.

Due to the connectedness and technology of the world today, different societies on different continents are able to interact readily. This allows for technology and new beneficial developments to spread from society to society throughout the world. Because of trade, plants and animals that are only able to grow in certain conditions can be used by many different societies.