has with other places, the more it will be exposed to new ideas and technologies. A place with air and seaports, road networks, and government policies that facilitate the movement of goods and people will tend to be more innovative and be the origin point for new ideas and technologies. The same holds true for communications network connections. Places that are linked by telephone and internet connections allow for the quick movement of information, which fosters creativity and the formation of new ideas (figure 1.33). Thus, spatial interaction results from connectivity and accessibility. Transportation and communications networks connect locations, allowing people, ideas, and things to have access to different places.
Figure 1.32.Live poultry market in China. Geographers and others see parts of Asia as being the most likely origin point for an avian flu pandemic. High population densities, poor sanitation, and close interaction between chickens and humans create ripe conditions for disease. Photo by Fotokon. Stock photo ID: 186029792. Shutterstock.
Figure 1.33.Internet café in Indonesia. People access the internet with cell phones and laptop computers at a café in Indonesia. Communications networks are an essential component of spatial interaction. When places are connected in this way, ideas and innovation spread. Photo by Lano Lan. Stock photo ID: 344025836. Shutterstock.
Spatial interaction is strongly influenced by distance. This influence is described by Tobler’s first law of geography, which states that “everything is related to everything else, but near things are more related than distant things.” The same concept can be described as distance decay, whereby there is more interaction between places that are close together than between places that are far apart (figure 1.34).
For instance, Mexican cities along the US border will be more like US cities, while Mexican cities in southern Mexico are less similar. Northern cities have more signage in English, people use more Spanglish terms, and the latest consumer goods from the US are more prevalent than in southern Mexican cities. This is because of greater spatial interaction—good connectivity and accessibility via roads and border crossings as well as TV and radio signals. This is also because of a greater diffusion of US culture and goods, especially through relocation and contagious diffusion. As one moves south from the US border, the influence of the English language and of American products and culture becomes less pronounced.
The same can be seen with Mexican influence in US cities along the southern border, where Mexican language, food, music, and other cultural features are more prevalent. Moving north, Mexican cultural influence declines as distance increases from the border.
Figure 1.34.Distance decay. Image by author.
Geographers also study spatial interaction in terms of core and periphery. Core areas include concentrations of things such as political power, economic activity, specific cultural characteristics, or population density. The periphery includes surrounding areas that have spatial interaction with the core. Often, the core is seen as having an advantageous position relative to the periphery. For instance, a political core makes laws that govern the periphery under its control, while an economic core creates wealth by using labor and natural resources from its periphery. At a global scale, core and periphery have been used to describe how wealthy countries (i.e., the core) exploit poor countries (i.e., the periphery) by extracting natural resources.
Core and periphery can also be seen in terms of regions, whereby the core of a region constitutes a heavy concentration of regional characteristics, while the periphery is the area where the characteristics gradually diminish. For instance, Louisiana may be considered part of the core of the South, but Texas can be seen as part of the periphery, as southern music, food, and dialects gradually fade as one moves west.
With advances in communication and transportation technologies, some geographers refer to space-time compression. This is the idea that the world is “shrinking” as relative distance declines with changes in technology. New ideas now travel instantly to different places via communications technology, and people and goods move rapidly by car, ship, and airplane. As places become “closer” together, change brought about through spatial interaction happens more quickly. Global pop music stars now influence youth fashion around the world at the same time rather than just in smaller local or regional markets. Similarly, the 2008 financial crisis that began with banks in the United States quickly impacted the global economy. Whereas music, fashion, and economic crises were once local phenomena or spread slowly, they now impact people around the world in a short period of time.
Spatial diffusion
Spatial diffusion is another way that characteristics spread to new locations. From an origin point, an idea or thing can diffuse to new places, where it can then combine with other ideas or things and form something new.
Spatial diffusion can be broken down into two broad categories: relocation diffusion and expansion diffusion.
Relocation diffusion occurs when people move to a new location and take their ideas and possessions with them. With relocation diffusion, the number of people using a particular idea or possession does not change, but the place where they are used does change. When Spaniards first migrated to the Americas, they brought their religious ideas and weapons with them. Thus, via relocation diffusion, Christianity and European military technology spread to the New World. This diffusion process occurred even before the indigenous people of the Americas began practicing Christianity and using steel weapons.
Likewise, Latin American culture has diffused to many parts of North America as Latino immigrants relocate north (figure 1.35). The Spanish language, food, music, and other cultural elements can now be found in many American and Canadian cities, specifically because of relocation diffusion.
Figure 1.35.Ecuadorian restaurant in New York. Latino immigrants bring their culture with them through the process of relocation diffusion. Photo by Lee Snider Photo Images. Stock photo ID: 426459184. Shutterstock.
Expansion diffusion occurs when the number of people using an idea or item increases. This type of diffusion resulted as Spaniards in the Americas converted the indigenous population to Christianity and the indigenous people began using and making steel weapons. Likewise, many nonimmigrants in North America now eat foods from Latin America and know a few words or phrases in Spanish (“Hasta la vista, baby”). Via expansion diffusion, culture and technology spread to new people.
Expansion diffusion can be broken down into contagious diffusion and hierarchical diffusion. Contagious diffusion is when a characteristic spreads from person to person on the basis of proximity. In a sense, it can be visualized as when a pebble is thrown in a pond and the waves move outward in a circular pattern (figure 1.36). Places close to the origin point adapt the new idea or item before places that are farther away do. Using the example of Spaniards in the Americas, the first indigenous people to be converted to Christianity and to use steel would be those who lived close to early Spanish settlements. Diffusion to indigenous people in more remote locations took much longer. Similarly, more people in the American Southwest than in other US areas eat dishes from Latin America due to their proximity to the southern border and Latino immigrant communities in southwestern cities. Over time however, Latino culture has spread to places beyond the border and immigrant-heavy cities. Guacamole is now a staple throughout the United States during the most all-American of events, the Super Bowl.
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