Humanities › Geography Common Geography Terms: Diffusion How Things Spread From Place to Place Share Flipboard Email Print JP Amet / Getty Images Geography Basics Physical Geography Political Geography Population Country Information Key Figures & Milestones Maps Urban Geography By Matt Rosenberg Geography Expert M.A., Geography, California State University - Northridge B.A., Geography, University of California - Davis Matt Rosenberg is an award-winning geographer and the author of "The Handy Geography Answer Book" and "The Geography Bee Complete Preparation Handbook." our editorial process Matt Rosenberg Updated July 11, 2019 In geography, the term diffusion refers to the spread of people, things, ideas, cultural practices, disease, technology, weather, and other factors from place to place. This kind of proliferation is known as spatial diffusion. The three main types of this phenomenon are expansion diffusion, stimulus diffusion, and relocation diffusion. Spatial Globalization is a form of spatial diffusion. Inside the home of an average American couple, you'll find a good example of globalization. For instance, a woman's handbag may have been made in France, her computer in China, while her spouse's shoes may have come from Italy, his car from Germany, hers from Japan, and their furniture from Denmark. Spatial diffusion begins at a clear point of origin and spreads from there. How quickly and through what channels the diffusion spreads determines its class or category. Contagious and Hierarchal Expansion Expansion diffusion comes in two types: contagious and hierarchal. Infectious diseases are a prime example of contagious expansion. A disease follows no rules, nor does it recognize borders as it spreads. A forest fire is another example that fits this category. In the case of social media, memes and viral videos spread from person to person in contagious expansion diffusion as they are shared. It's no coincidence that something that spreads quickly and widely on social media is deemed "going viral." Religions spread through contagious diffusion as well, as people must come in contact with a belief system to somehow to learn about and adopt it. Hierarchical diffusion follows a chain of command, something you see in business, government, and the military. The CEO of a company or the leader of a government body generally knows information before it is disseminated among a wider employee base or the general public. Fads and trends that start with one community before spreading to the wider public can also be hierarchical. Hip-hop music springing up in urban centers is one example. Slang expressions that owe their genesis to one particular age group before being more widely adopted—and perhaps eventually making it into the dictionary—would be another. Stimulus In stimulus diffusion, a trend catches on but is changed as it is adopted by different groups, such as when a certain religion is adopted by a population but the practices are blended with the customs of the existing culture. When slaves brought Voodoo, which has its origins in African tradition, to America, it was blended with Christianity, incorporating many of that religion's important saints. Stimulus diffusion can also apply to the more mundane as well. "Cat yoga," an exercise fad in the United States, is much different than the traditional meditative practice. Another example would be the menus of McDonald's restaurants from around the world. While they resemble the original, many have been adapted to suit local tastes and regional religious food doctrines. Relocation In relocation diffusion, that which moves leaves behind its point of origin but rather than simply being changed along the way or changing when it arrives at a new destination, it may also change points along the journey as well as the eventual destination, simply by being introduced there. In nature, relocation diffusion can be illustrated by the movement of air masses that spawn storms as they spread across a landscape. When people immigrate from country to country—or simply move from the country to the city—they often share cultural traditions and practices with their new community when they arrive. These traditions may even be adopted by their new neighbors. (This is especially true of food traditions.) Relocation diffusion can occur in the business community as well. When new employees come to a company with good ideas from their previous workplaces, smart employers will recognize the found knowledge as an opportunity and leverage it improve their own companies.