Diffusion The process of dissemination, the spread of an idea or innovation from its hearth to other areas.

Barriers to diffusion  Physical barriers in nature: rivers, oceans, lakes, and mountain ranges.  Cultural religious beliefs. language  impedes the easy flow of ideas and fads from the United States and English-speaking Canada to French Canadians in Québec.  Political boundary can impede or slow down the dissemination of disease.  Economic factors people in certain places cannot afford to purchase a new commodity or technological innovation.

Types of Diffusion  Expansion Diffusion – idea or innovation spreads outward from the hearth Contagious Hierarchical Stimulus  Relocation Diffusion- migrants bring an idea/innovation physically to a place

Worldwide, there are 1.4 billion followers of Islam There are between 5 – 7 million Muslims in the United States Diffusion of Islam 630 – 1600 AD

 Hierarchical Diffusion- ideas/artifacts spread between larger places or social elite  later to smaller places or less prominent people  Fashion trends  Cell phone use in the early 1990s

Music and Clothing (hierarchical diffusion)  New clothing and music fads, for example, spread quickly among major world cities such as New York, Los Angeles, London, Paris, and Tokyo.  Only later do they filter down the urban hierarchy

Starbucks.. They're everywhere

Contagious Diffusion  All individuals and areas outward from the source region are affected  Term implies direct contact  Usually associated with disease

Distribution of West Nile Virus: Humans, Birds, & Mosquitos, 2001

Diffusion of Africanized Bees after their arrival to Brazil, South America

Relocation Diffusion  Spread of culture through physical movement  Language, religion, food preferences  Can show spotty spatial distribution

Hmong Refugees from Laos

Spanish and Portuguese Colonies

Stimulus Diffusion (trans cultural)  Takes part of an idea to create an innovative product  Computer keyboards, Cherokee writing system, gang culture fashions, Siberian reindeer herding.

Summary  Diffusion: the process of dissemination, the spread of an idea or innovation from its hearth to other areas.  Relocation diffusion: The spread of idea by physical movement of people from one place to another. Ex: spread of language and culture from new migrants to America

Summary  Expansion Diffusion: Spread of idea from one place to another by snowballing. This can happen in three ways. Hierarchal Diffusion: Spread of an idea from people (nodes) of authority or power to other persons or places (Ex: hip-hop/rap music) Contagious Diffusion: Rapid and widespread diffusion of a characteristic throughout the population (Ex: ideas placed on the internet) Stimulus diffusion: the spread of an underlying principle, even though a characteristic itself apparently fails to diffuse. (Ex: PC & Apple competition, p40) Characteristic throughout the population