Vigilance to Spatialized Auditory Displays: Initial Assessment of Performance and Workload

Objective The present study was designed to evaluate human performance and workload associated with an auditory vigilance task that required spatial discrimination of auditory stimuli. Background Spatial auditory displays have been increasingly developed and implemented into settings that require vigilance toward auditory spatial discrimination and localization (e.g., collision avoidance warnings). Research has yet to determine whether a vigilance decrement could impede performance in such applications. Method Participants completed a 40-minute auditory vigilance task in either a spatial discrimination condition or a temporal discrimination condition. In the spatial discrimination condition, participants differentiated sounds based on differences in spatial location. In the temporal discrimination condition, participants differentiated sounds based on differences in stimulus duration. Results Correct detections and false alarms declined during the vigilance task, and each did so at a similar rate in both conditions. The overall level of correct detections did not differ significantly between conditions, but false alarms occurred more frequently within the spatial discrimination condition than in the temporal discrimination condition. NASA-TLX ratings and pupil diameter measurements indicated no differences in workload. Conclusion Results indicated that tasks requiring auditory spatial discrimination can induce a vigilance decrement; and they may result in inferior vigilance performance, compared to tasks requiring discrimination of auditory duration. Application Vigilance decrements may impede performance and safety in settings that depend on sustained attention to spatial auditory displays. Display designers should also be aware that auditory displays that require users to discriminate differences in spatial location may result in poorer discrimination performance than non-spatial displays.