Operator Functional State

The term ‘operator functional state’ (OFS) acknowledges the intrinsic relationship between human task performance and the background state of the individual. Although central to an understanding of all aspects of performance, OFS, as its name implies, is of particular relevance to the behavior of operators of industrial control processes – chemical and nuclear plants, aviation, air traffic control, shipping, railways. The demands of managing complex control systems, particularly those that have safety-critical features, mean that operators cannot usually relax when they feel tense, or take breaks when they are tired. Instead, they must sustain high levels of task-directed effort for long periods, giving rise to strain, fatigue and unwanted after effects of work. The OFS approach recognizes the active nature of this adaptation to work goals and personal state, and argues for a methodology based on the necessity of examining the relationship between these processes under task conditions. The relationships between workload, effort, performance and fatigue, and the use of psychophysiological methods to investigate them, are at the heart of research in this area. Such issues are strongly represented in the papers that make up the present volume, which are based on the proceedings of a NATO Advanced Research Workshop (ARW).