What Does Computer-Mediated Control of a Thermal-Hydraulic System Have to Do With Moving Your Jaw to Speak? Evidence for Synergies in Process Control

Coordination phenomena can take many diverse forms, but ecological psychologists have focused primarily on understanding human motor control. In this article we report an experiment on human-machine coordination that was designed to replicate and extend an early experiment on human jaw movement during speech production that provided initial evidence of synergies. Participants controlled a thermal-hydraulic process simulation for about 1 hr per weekday for approximately 1 month. Half of the participants used a human-computer interface that presented predominantly lower level physical (P) information, whereas the other half used an interface that presented higher level functional (P+F) information as well. During the last block of trials, local perturbations were introduced by increasing the time constant of a particular component per trial by a factor of 20. The component perturbations had less impact on the performance of the P+F participants than the P, and this effect was mostly localized to components that had alternative degrees of freedom for control. Most important, the P+F participants exhibited more evidence of higher level control than the P, providing some initial evidence for synergies in process control. These findings suggest that it may be possible to develop a general unified theory of coordination that subsumes motor control and human-machine interaction as special cases.