Propagation in Networks : the impact of information processing at the actor level on system-wide propagation dynamics

Often systems can exhibit behavior which is diffcult to predict and steer. Interactions on the micro level (between actors within the system) result in propagation of behavior which can cause unforeseen dynamics on the system level. Understanding the effects of propagation, the process by which connected actors in uence each other, therefore is crucial in order to understand how the state and behavior of a system will change.

Propagation literature has primary considered the way in which propagation dynamics scale from the local to the system-level, identifying the network structure as prime driver in this process. By focusing on the network structure, the impact of the mechanism by which propagation takes place has however been pushed to the background. In this dissertation it is argued that it is this mechanism which plays a crucial role in determining how propagation dynamics scale from the local to the system-level.

To map the mechanism of propagation, this dissertation puts forward a framework for propagation as an information processing process. It describes the propagation mechanism using the distinct sub-processes; sending out information (Radiation), transferring information (Transmission) and processing information (Reception).

This dissertation shows that using such a framework not only results in a more detailed and methodologically stronger model of propagation, but also that distinguishing these sub-processes is a prerequisite for effective interventions into propagation. It also shows that heterogeneity in different part of the mechanism have radically different effects on the dynamics at the system-level. This implies that specifying the mechanism is critical for understanding the system-level dynamics in cases of heterogeneous actor behavior. Finally, it shows that the effects of network structure are highly conditional on the mechanism of propagation. When more complex propagation mechanisms are compared, a single network structure can result in very different dynamics at the system level.

As such, this dissertation identifies the mechanism of propagation as a critical component in understanding how micro-level behavior scales toward the system-level, and hence impacts system-wide dynamics