Every culture trait starts somewhere, at a hearth, and spreads, or diffuses, from there. Distance decay explains why nearby places usually adopt a trait first. Geographers name the ways traits spread.
Key idea
Relocation diffusion: people carry the trait when they move. Expansion diffusion: the trait spreads outward while staying strong at home. It has three kinds: contagious (person to person, to the nearest places first), hierarchical (from big or powerful places to smaller ones, skipping places in between) and stimulus (the underlying idea spreads, but people change the trait to fit their own culture).
Why it works
The kind of diffusion depends on how people come into contact. A joke spreads by contact, so it moves like a ripple. A new fashion often starts in a few large, connected cities, because that is where designers, media and travelers meet, then reaches smaller towns later. When migrants settle far away, the trait jumps with them. And when a trait clashes with local beliefs or tastes, people keep the idea but change the details.
Worked examples
Worked example: Naming the kind
Classify: (a) English spreading to Australia with British settlers; (b) a fast-food chain in India selling vegetarian burgers instead of beef; (c) a new phone first sold in the largest cities, then in small towns.
- (a) Settlers carried the language to a new land: relocation.
- (b) The idea (fast-food burgers) spread, but it changed to fit local diets: stimulus.
- (c) It moved down from the largest places to smaller ones: hierarchical.
Answer: (a) relocation, (b) stimulus, (c) hierarchical.
Worked example: Contagious diffusion
A rumor in a school moves from one friend group to the next, classroom by classroom. Which kind?
- It spreads by direct contact to the nearest people.
- Nobody carries it to a distant place, and big places are not skipped to.
Answer: Contagious diffusion.
Common mistake
Students call any spread "contagious." Check the path. If a trend jumps from big city to big city before reaching small towns, it is hierarchical. If migrants carry it to a new land, it is relocation. If the idea arrives but is changed to fit local culture, it is stimulus. Contagious diffusion moves outward to the nearest places first, like a ripple.