The expanded use of automation has altered the role of operators in many work settings from that of being active controllers to more passive monitors who must stay attentive to displays and take action only intermittently. Some examples where monitoring plays a crucial role include baggage screening, security operations, and medical monitoring. This article reports on a study in which the workload and stress associated with a 40-min vigilance task were examined under conditions where observers monitored an auditory or a visual display for changes in signal duration. Results showed scores that fell in the midrange of the NASA Task Load Index, with scores on the Frustration subscale increasing linearly over time. Signal detection favored the auditory mode. The authors conclude sustained attention is stressful. The authors stress that display mode and time on task should be considered carefully in the design of operations requiring sustained attention in order to enhance performance and reduce stress.
Abstract