In the column http://www.straightdope.com/classics/a1_250.html , Cecil says that in the Old World Sumer invented the wheel and everyone else got the idea from them. Sumer was basically the cool kid of the Stone Age.
Well, I’m wondering: does that apply to China and Korea and that general area? Did the villagers along the Yangtze river copy traders, or develop the wheel for themselves? Or did they do it and not use it? Or something else entirely?
The spread of ideas, disease, and tools all indirectly can be attributed to trade. While the wheel may have it’s origins in Sumer, trade with the village in the next river valley probably is the mechanism for the idea of a wheel getting around (no pun intended). Repeat this scenario several hundred times and eventually all people along the trade routes learned about it – all the way to China. They also shared germs, religion, and other types of hangers-on while trading. When the Spanish landed in Mexico in the early 1500s, they not only shared their religion with the natives, but small pox, and horses too (both of which were not known in the New World, either). The Aztecs gave them peppers, potatoes, and syphilis. Trade had begun!
Now, with regards to why some cultures did not readily adopt, or independently invent the wheel, it probably has much to do with terrain. Take the Incas or other peoples of Central and South America. In Mexico there are thick jungles, and in Peru there are steep mountains. As Cecil points out, there were no draft animals for clearing roads and paths - work people tend not to do with their bare hands – hence no great advantage for carts and such. However, I am imagining that in Sumer, it may have been a drier, flatter area with domesticated draft animals – so an advantage to have the wheel and cart invented.
The Incas and Aztecs did have great knowledge of things that were practical to them, such as astronomy, mathematics, and warfare. However, evidently, they had no great need for wheels - and no roads. As Cecil points out – they knew about it, but had no practical purpose for it.
Incidentally, I think this topic folds nicely into the discussion on European influences on exploration and dominance:
http://www.straightdope.com/classics/a970620.html
Having competition leads people to invent things and trade ideas (and build resistance to germs). A closed or isolated society will not have these benefits.
harrmill