Stress and performance in complex domains: a psychophysiological field study of a command-and-control system

Work in complex domains, such as aircraft cockpits and process control rooms, places considerable demands on the human operator. In such exacting environments stress levels are high, and it is critical that the design of computer-based systems should not add to the pressures on operators. Indeed, the aim of reducing stress would seem a highly desirable design goal given the pernicious effects of stress on human well-being and performance. In this paper, the author argues that the virtuous circle of reduced stress and increased performance is the hallmark of a well-designed system. A field study is outlined of the implementation of a computerised command-and-control system in an ambulance service. The aim of the work was to evaluate the impact of the new system on operator stress levels and to identify those design features that had a key influence on the outcome. An important feature of the study was the use of a psychophysiological methodology in order to allow stress to be measured at both subjective and physiological levels during real-time operational conditions.