Guns, Germs, and Steel: the Fate of human societies” is an amazing book by Jared Diamond, who is winner of numerous awards including the Pulitzer Prize (for this book), MacArthur Foundation fellowship and the 1999 National Medal of Science.

Diamond was researching bird ecologies and migratory patterns on the coast of New Guinea when he happened to have a conversation with a local politician named Yali, who was then helping the native New Guineans start to administrate themselves when the eastern half of the island gained it’s independence in the early 1970’s. Among other questions, he asked Diamond a fairly simple question, but with an extremely complex answer.

“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?”

His fundamental question, the question Diamond tries to answer in his book, is why did some cultures dominate other cultures in the past? Keep in mind that this is not a racist book, and he goes so far as to even (in his mind) claim that possibly the average New Guinean is smarter than the average European (due to the fact that New Guineans have to deal with life and death situations every day that constitute a much tougher and mentally demanding environment). The book instead focuses on the environmental reasons why some cultures dominate others.

His basic response, which he explains in around 400+ pages, is a set of four main factors:
  1. Continental differences in wild plant and animal species available initially for domestication. Eurasia (he treats all of Asia, Europe and for the most part Northern Africa as one continent) for the most part had the vast majority of large docile pack animals, which were ideal for domestication, while the Americas had only one animal (other than the dog) domesticated before 1492, the llama.

  2. Rates of diffusion and migration inside a continent. It is much easier to move east/west through a similer climate physically and culturally than to move north and south. To travel from France to Japan, even though there are great distances involved, requires fairly few changes in basic climate, day length, etc. The various environments required to moved from South America to North America, including deserts, jungles, mountains, etc., are much more of a barrier to technological diffusion and cultural spread.

  3. Rates of diffusion from continent to continent. Africas main source of domesticated animals was the Fertile Crescent region in Asia, which was also a large source of it’s domesticated food, which allowed intensified agriculture. The Americas were isolated from all other cultures (with some very limited exceptions), which kept them from using domesticated animals not present locally to help in agriculture and in technological diffusion.

  4. Continental differences in area and population. The size of Eurasia has been of great advantage, with it’s multitudes of climates, locales, and indigenous people. Australia has a much more limited environment without that advantage, and the land it does have is not suitable for farming (plus it didn’t have any useful domesticatable plants). The Americas were fragmented climatically and geographically, which effectually rendered the Americas into several smaller continents.
This book is amazing because it does something that (to the best of my knowledge and his) has not really been done before: it takes a scientific approach to history. Other sciences have been scoffed at by physicists as not being true sciences, such as biology and paleontology. Classical scientists say that to be a true science you must be able to have experiments, be able to reproduce results, and predict things successfully.

He uses many natural experiments to prove his hypothesizes, some of which include

  1. New Guinea, from which he himself has spent much time.

  2. Australia and Tasmania, and their supposed “backwardness” which was more caused by the lack of domesticated plants and animals that forced them to remain in a hunter-gatherer lifestyle.

  3. Polynesia, which he uses as the proof that one can look at history this way. Almost identical (culturally and technologically) Austronesian people colonized many different types of environments and subsequently developed predictably according to the type of islands they lived on.

  4. Sub-Saharan Africa, where he describes the colonizing effect of Bantu farmers had on the OTHER native Africans that we Americans tend to forget about, the Khoisan and Pygmy peoples. Since food production developed in the Sahel region of Africa (West Africa), the people there (Bantu) had a natural numerically advantage against the other southern Africans.

  5. The multitudes of Native American peoples, and the difficulty technology and food had in traveling the seemingly short distance between Mississippi, Mesoamerica and South America.
The Science of History does not have reproducible results, as you cannot experiment with indigenous people ethically. On the other hand, doctors use scientific methods to understand why a patient becomes ill.

Diamond uses scientific methods to understand why cultures are distributed the way they are, why super powers exist in the places that they do, and why race has nothing to do with it, that it’s all in the environment. He hopes that this outlook on the past can help us understand how today has been shaped, so that we have a better command of the future.

As wharfinger points out, the ease of east/west travel by cultures is mainly due to the fact that people bringing their previously domesticated plants generally stay where the plants would thrive, which is at about the same latitude, where the growing season and other factors remain about the same.