A short history boy moment before digging into the details of these ideas. I was first introduced to the ‘core-periphery’ relationship in a high school history class, where it was used to describe the economic relations of former colonizing countries to their former colonies. These economic relationships of subordination remain in place today.*
* In retrospect, some of my high school classes were pretty radical compared to a lot of people’s.
But I had never taken enough sociology courses over the years to have seen how ubiquitous this concept is in the analytic frameworks of social network theory. In the abstract context of social network analysis, the core is simply another word for a hub. One node would have many other nodes directly connected to it, but those connected nodes would have only that connection to the central node and perhaps one or two others.
It’s the social structure of the elite and the masses, and it arises in all human group interactions and structures. Some people are especially well-connected to many others through many different relationships and institutions, and the majority of others have more sparse connections, perhaps only through a single group.
As the networks get larger and more complex, the analysis of what constitutes a core and its periphery becomes two-dimensional. When there are multiple core nodes, they connect not only to their periphery nodes, but also to each other. In a typical network, the periphery nodes are connected only to their core nodes, but generally not to each other.
This much about network structure I already knew. The next part (literally the next page in Charles Kadushin’s Understanding Social Networks), was an education for me.
The caucus model of the core-periphery relationship depicts a network where the most heavily connected nodes are mostly only connected with each other. The peripheral nodes here are almost entirely isolated, with no connection either to a hub or to each other. They simply drift around the outside.
Another modified relationship sees the core nodes as densely interconnected and with many peripheral connections too, but the peripheral nodes are isolated from each other. The flow of information along networks is important to distinguishing this model, emphasizing how important dynamism is to networked relations.
So it looks like an ordinary core-periphery relationship defining the network, but the only two-way information flow is between hubs. Information flows from peripheral nodes to their hubs, but not from the hubs back out to their peripheral nodes. The peripheral nodes don’t belong to the core’s club, but the core sends messages to the periphery.
|Sociological theory can sometimes be|
delightfully irreverent, like when abstract
social network models are named after film
comedy stars of the 1930s.
“I wouldn't belong to any club that would have me as a member,” goes the mantra of this model. At least that’s how they treat it in the introductory literature. That’s why Kadushin calls this the Groucho Marx model.
The model that Kadushin calls Deference also depends on dynamism to understand it. Hubs connect to each other and their own peripheral nodes, but the peripherals are connected with each other as well, sometimes across the peripheries of multiple cores. What stands out are the flows of information: hubs communicate with each other, but not to their peripheral nodes, while the peripherals send information every which way they can.
For the sake of filling out a summary of abstract possibilities, Kadushin mentions one last model that he says almost never happens in real networks. This is where the hubs not only communicate very little, but are not even well-connected to each other. The peripheral nodes, however, are all connected throughout the network, sending messages back and forth, but largely ignoring the core.
Kadushin doesn’t go into detail about what this would look like, but I imagine the connections among peripheral nodes would be centreless, with few hubs dominating connectivity to forge a new core. Almost rhizomatic. He refers to it through the mainstream American notion, derived from its Christian heritage, that “the meek shall inherit the Earth.”
I’ll call it by a more atheistic name that shows just how radical it is: mass communication among peripheral communities to marginalize the elite. No matter how abstract we may get in our analyses, there’s always a political meaning to all social network relations.
In real networks, there’s rarely such a clear delineation between core and periphery nodes. The distinction changes smoothly as you analyze a network. There are clearly centrally located core nodes with many direct connections, and there are obvious isolated peripheral nodes.
But there are also nodes that have a few connections of their own, perhaps also to multiple core nodes. There are some core nodes that are connected mostly to other cores, or whose core-periphery networks themselves are fairly isolated from the broader network.
All these complicating factors can’t always be depicted in the pure conceptual categories of analysis, which are even more abstract than the already abstract network diagrams. Such is the inevitable complication of real life over our models of it. It even complicates the models themselves.