Multiplexed Networks

Strands and Layers: Interlocking Content

As actors develop or layer more relations within a tie, the tie becomes more multiplex and creates a more [Page 558]complex structural form. The interlocking of content flows can create dependencies that function to constrain or to enhance the flow of one type of network content conditional on the flow of another. For example, when an actor's work interactions are embedded within a social relationship (relational embeddedness), work-related decisions may be constrained by the actor's need to maintain the social relationship. Conversely, the social relationship may positively facilitate work-related resource acquisition for the actor.

As dyadic ties combine to create larger network structures, tie multiplexity combines to create multirelational networks with structural subcomponents sharing similar relational content. Multiplexed networks represent the layering of multiple exchange relations into a single network structure. Each set of relations represents a specific subnetwork, or content slice of the network, defined by its own adjacency matrix and creating its own structure. For example, a multiplex network of school principals is layered with several content subnetworks that facilitate the flow of different exchanges, such as physical resources, social/emotional support, professional development, and coordination of student teachers. While some richly multiplex ties in this network will contain all of these contents, others may only serve a single type of exchange. This structure can be comprehended by first identifying the various relation or content layers and then observing the interlayer connections or couplings that are created where a common actor exists across multiple layers. This structure allows one network relation to influence another through the brokering role of common actors in each layer.

Business ties with actors in a corporate network can also overlap into a dating relationship and become a multiplexed network.

When a tie is multiplex, it is found in more than one layer. As a result, the tie can also function in a brokering role and influence exchange between network layers. Similar to how a tie in a single-relation network can fill a structural hole between network components and obtain an advantageous position of centrality, a multiplex tie can fill a structural hole between layers in a multiplex network and create cross-layer centrality for the actors. Given that an actor may have differential centrality in each layer depending upon their position within each subnetwork, actor centrality in multiplex networks needs to take into account the cumulative effect of cross-layer centralities. Actors may intentionally facilitate bridging subnetworks by increasing the multiplexity—adding or developing more relations—within a tie.

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