In cultural anthropology and cultural geography, cultural diffusion, as first conceptualized by Alfred L. Kroeber in his influential 1940 paper Stimulus Diffusion, or trans-cultural diffusion in later reformulations, is the spread of cultural items—such as ideas, styles, religions, technologies, languages etc.—between individuals, whether within a single culture or from one culture to another. It is distinct from the diffusion of innovations within a single culture.
Diffusion across cultures is a well-attested and also uncontroversial phenomenon. For example, the practice of agriculture is widely believed to have diffused from somewhere in the Middle East to all of Eurasia, less than 10,000 years ago, having been adopted by many pre-existing cultures. Other established examples of diffusion include the spread of the war chariot and iron smelting in ancient times, and the use of cars and Western business suits in the 20th century.
- Expansion diffusion: an innovation or idea that develops in a source area and remains strong there, while also spreading outward to other areas.
- Relocation diffusion:an idea or innovation that migrates into new areas, leaving behind its origin or source of the cultural trait.
- Hierarchical diffusion: an idea or innovation that spreads by moving from larger to smaller places, often with little regard to the distance between places, and often influenced by social elites.
- Contagious diffusion: an idea or innovation based on person-to-person contact within a given population.
Inter-cultural diffusion can happen in many ways. Migrating populations will carry their culture with them. Ideas can be carried by trans-cultural visitors, such as merchants, explorers, soldiers, diplomats, slaves, and hired artisans. Technology diffusion has often occurred by one society luring skilled scientists or workers by payments or other inducement. Trans-cultural marriages between two neighboring or interspersed cultures have also contributed. Among literate societies, diffusion can happen through letters or books (and, in modern times, through other media as well).
There are three categories of diffusion mechanisms:
- Direct diffusion is when two cultures are very close to each other, resulting in intermarriage, trade, and even warfare. An example of direct diffusion is between the United States and Canada, where the people living on the border of these two countries engage in hockey, which started in Canada, and baseball, which is popular in American culture.
- Forced diffusion occurs when one culture subjugates (conquers or enslaves) another culture and forces its own customs on the conquered people. An example would be the forced Christianization of the indigenous populations of the Americas by the Spanish, French, English and Portuguese, or the forced Islamization of West African peoples by the Fula[dubious ] or of the Nuristanis by the Afghans.
- Indirect diffusion happens when traits are passed from one culture through a middleman to another culture, without the first and final cultures ever being in direct contact. An example could be the presence of Mexican food in Canada, since a large territory (the United States) lies in between.
Direct diffusion is very common in ancient times, when small groups, or bands, of humans lived in adjoining settlements. Indirect diffusion is very common in today's world, because of the mass media and the invention of the Internet. Of interests also is the work of American historian and critic Daniel J. Boorstin in his book The Discoverers, in which he provides an historical perspective about the role of explorers in History in the diffusion of innovations between civilizations.
The many models that have been proposed for inter-cultural diffusion are
- Hyperdiffusionism —the theory that all cultures originated from one culture.
- Culture circles diffusionism (Kulturkreise)—the theory that cultures originated from a small number of cultures.
- Evolutionary diffusionism—the theory that societies are influenced by others and that all humans share psychological traits that make them equally likely to innovate, resulting in development of similar innovations in isolation.
- Mallory's "Kulturkugel" (a German compound meaning "culture bullet", coined by Mallory himself), a term suggested by J. P. Mallory to model the scale of invasion vs. gradual migration vs. diffusion. According to this model, local continuity of material culture and social organization is stronger than linguistic continuity, so that cultural contact or limited migration regularly leads to linguistic changes without affecting material culture or social organization.
A concept that has often been mentioned in this regard, which may be framed in the evolutionary diffusionism model, is that of "an idea whose time has come" — whereby a new cultural item appears almost simultaneously and independently in several widely separated places, after certain prerequisite items have diffused across the respective communities. This concept has been invoked, for example, with regard to the development of calculus by Newton and Leibnitz, or the inventions of the airplane and of the electronic computer.
Hyperdiffusionists deny that parallel evolution or independent invention took place to any great extent throughout history, they claim that all major inventions and all cultures can be traced back to a single culture.
Early theories of hyperdiffusionism can be traced back to ideas about South America being the origin of mankind. Antonio de León Pinelo, a Spaniard who settled in Bolivia, claimed in his book Paraíso en al Nuevo Mundo that the Garden of Eden and the creation of man had occurred in Bolivia and that the rest of the world was populated by migrations from there. Similar ideas were also held by Emeterio Villamil de Rada, in his book La Lengua de Adán he attempted to prove that Aymara was the original language of mankind and that humanity had originated in Sorata in the Bolivian Andes. The first scientific defence of humanity originating in South America came from the Argentine paleontologist Florentino Ameghino in 1880. Ameghino published his research in a book titled La antigüedad del hombre en el Plata.
There was a revival of hyperdiffusionism in 1911 with the work of Grafton Elliot Smith who asserted that copper spread from Egypt to the rest of the world along with megalithic culture. Smith had claimed that all major inventions had been made by the ancient Egyptians and were carried to the rest of the world by migrants and voyagers. His views became known as "Egyptocentric-Hyperdiffusionism". William James Perry elaborated on the hyperdiffusionist ideas of Smith by using ethnographic data. Another hyperdiffusionist was Lord Raglan in his book How Came Civilization (1939) he wrote that instead of Egypt all culture and civilization had come from Mesopotamia. Hyperdiffusionism after this did not entirely disappear, but it was generally abandoned by mainstream academia.
A noteworthy example of diffusion theory is the massive infusion of technology into Europe between 1000 and 1700 CE. In the early Middle Ages, Byzantine and Asian societies were far more advanced than Europe, however, the era beginning in the High Middle Ages reversed that balance and resulted in a Europe which surpassed Asian, Byzantine and Muslim cultures in pre-industrial technology. Diffusion theory has been advanced as an explanation for this shift in technological development. Many important basic inventions had their roots elsewhere, notably gunpowder, clock mechanisms, shipbuilding, paper and the windmill, however, in each of these cases Europeans not only adopted the technologies, but improved the manufacturing scale, inherent technology, and applications to a point clearly surpassing the evolution of the original invention in its country of origin. Historians have questioned recently whether Europe really owes the development of such inventions as gunpowder, the compass, the windmill or printing to the Chinese or other cultures. It is a matter of record that by the late eighteenth century, European fleets, armed with advanced cannon, decimated Arab and Chinese fleets, paving the way for unfettered domination of the seas that led to the colonial era.
While the concept of diffusion is well accepted in general, conjectures about the existence or the extent of diffusion in some specific contexts have been hotly disputed. An example of such disputes is the proposal by Thor Heyerdahl that similarities between the culture of Polynesia and the pre-Columbian civilizations of the Andes are due to diffusion from the latter to the former—a theory that currently has few supporters among professional anthropologists.
Attempts to explain similarities between two cultures by diffusion are often criticized for being ethnocentric, since they imply that the supposed "receptors" would not be capable of innovation. In fact, some authors made such claims explicitly—for example, to argue for pre-Columbian trans-oceanic contact as the "only possible explanation" for the origin of the great civilizations in the Andes and of Central America.
Those disputed are fueled in part by the overuse of cultural diffusion, starting in the late 19th century, as a blanket explanation for all similarities between widely dispersed cultures. The most famous proponent of this theory was Grafton Elliot Smith, who argued that civilization first formed in Ancient Egypt and then diffused to other places.
Diffusion theories also suffer from being inherently speculative and hard to prove or disprove; especially for relatively simple cultural items like "pyramid-shaped buildings", "solar deity", "row of standing stones", or "animal paintings in caves". After all, the act of diffusion proper is a purely mental (or at most verbal) phenomenon, that leaves no archaeological trace. Therefore, diffusion can be deduced with some certainty only when the similarities involve a relatively complex and partly arbitrary collection of items—such as a writing system, a complex myth, or a pantheon of several gods.
Another criticism that has been leveled at many diffusion proposals is the failure to explain why certain items were not diffused. For example, attempts to "explain" the New World civilizations by diffusion from Europe or Egypt should explain why a basic concept like the potter's wheel is not found in the Americas while writing is.
Major contributors to inter-cultural diffusion research and theory include:
- Franz Boas
- James Burnett, Lord Monboddo
- Leo Frobenius
- Cyrus H. Gordon
- Fritz Graebner
- A. C. Haddon
- Stephen C. Jett
- Alice Beck Kehoe
- David H. Kelley
- A. L. Kroeber
- E. Lorges
- William James Perry
- Friedrich Ratzel
- W. H. R. Rivers
- Everett Rogers
- Wilhelm Schmidt
- Grafton Elliot Smith
- E. B. Tylor
- Clark Wissler
- in the context of Indo-Aryan migration; Mallory, "A European Perspective on Indo-Europeans in Asia". In The Bronze Age and Early Iron Age Peoples of Eastern and Central Asia. Ed. Mair. Washington DC: Institute for the Study of Man (1998)
- the term is a 'half-facetious' mechanical analogy, imagining a "bullet" of which the tip is material culture and the "charge" language and social structure. Upon "intrusion" into a host culture, migrants will "shed" their material culture (the "tip") while possibly still maintaining their "charge" of language and, to a lesser extent, social customs (viz., the effect is a diaspora culture, which depending on the political situation may either form a substratum or a superstratum within the host culture).
- Legend and lore of the Americas before 1492: an encyclopedia of visitors, explorers, and immigrants, Ronald H. Fritze, 1993, p. 70
- Indians of the Andes: Aymaras and Quechuas, Harold Osborne, 2004, pp. 2–3
- The Routledge Dictionary of Anthropologists, Gérald Gaillard, 2004, p. 48
- Megaliths, Myths and Men: An Introduction to Astro-Archaeology, Peter Lancaster Brown, 2000, p. 267
- Sociocultural Evolution: Calculation and Contingency, Bruce G. Trigger, 1998, p. 101
- Carlo M. Cipolla, Before the Industrial revolution: European Society and Economy 1000–1700, W.W. Norton and Co., New York (1980) ISBN 0-393-95115-4
- Peter Jackson: The Mongols and the West, Pearson Longman 2005, p.315
- Donald F. Lach: Asia in the Making of Europe. 3 vols in 9, Chicago, Illinois, 1965–93; I:1, pp. 82–83
- Robert Bartlett: The Making of Europe. Conquest, Colonization and Cultural Change 950–1350, Allen Lane, 1993
- Kroeber, Alfred L. (1940). "Stimulus diffusion." American Anthropologist 42(1), Jan.–Mar., pp. 1–20.
- Rogers, Everett (1962) Diffusion of innovations. New York: Free Press of Glencoe, Macmillan Company.
- Sorenson, John L. & Carl L. Johannessen (2006) "Biological Evidence for Pre-Columbian Transoceanic Voyages." In: Contact and Exchange in the Ancient World. Ed. Victor H. Mair. University of Hawaii Press. Pp. 238–297. ISBN 978-0-8248-2884-4; ISBN 0-8248-2884-4
- "Diffusionism and Acculturation" by Gail King and Meghan Wright, Anthropological Theories, M.D. Murphy (ed.), Department of Anthropology, College of Arts and Sciences, The University of Alabama.