1. 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.

2. Types of Diffusion  Expansion Diffusion – idea or innovation spreads outward from the hearth Contagious Hierarchical stimulus  Relocation Diffusion- migrants bring an idea/innovation physically

3. 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

4.  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

5. 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,

6. Starbucks.. They're everywhere

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

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

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

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

13. Hmong Refugees from Laos

14. Spanish and Portuguese Colonies

15. 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.