Propagation of Representational State

The central analytical operation of distributed cognition theory is the tracing of representational states as they propagate across the components of a cognitive system. This is not a metaphorical gloss on communication. It is a precise description of the computational process by which a distributed system transforms inputs into outputs. When a bearing is observed, a representational state comes into existence at one point in the system. That state propagates: it is transformed into a verbal report, transmitted across the bridge, received by the recorder, inscribed in the log, translated into chart geometry, synthesized with other bearings to produce a position fix. The computation performed by the system is nothing other than this propagation — the movement of representational states across media, through transformations that alter the form of the information while preserving (or failing to preserve) its content. Speed and fidelity determine performance: a system in which states propagate quickly and accurately computes well; a system in which propagation is slow, noisy, or systematically distorted