How Ideas Travel: Cultural Diffusion

Cultural diffusion is the spread of ideas, practices and technologies from one society to another. Some diffusion is direct, through trade, migration or conquest, while some is indirect, passing through intermediaries over long distances. Paper is a classic case: invented in China, papermaking spread to the Islamic world by the 8th century, Baghdad had paper mills by the 790s, and the craft reached Europe through Muslim Spain and Italy centuries later.

Hindu-Arabic numerals followed a similar path, from Indian mathematicians through the Persian scholar al-Khwarizmi to Europe, where Fibonacci promoted them in 1202. Anthropologist Alfred Kroeber described stimulus diffusion, where an idea inspires a new invention rather than being copied, as when Sequoyah created a Cherokee writing system in 1821 after seeing English writing. Diffusion usually involves adaptation, so the borrowed idea changes in its new home. It is rarely a simple one-way transfer.