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.

Effects of state motivation in overload and underload vigilance task scenarios

Vigilance, or sustained attention, is the ability to maintain attention for prolonged periods of time. Interestingly, to date, few studies on vigilance have focused on the role of state motivation in sustaining attention. To address this disparity in the literature, the present study examined the effect of two types of state motivation on vigilance performance across task types (cognitive or sensory) and across the number of displays (one, two, or four). A sample of 105 participants completed a 24-min overload or underload vigilance task in a research laboratory. Participants were randomly assigned to either a cognitive or sensory vigilance task, and were randomly assigned to monitor one, two, or four displays for target stimuli. The results indicated that intrinsic state motivation predicted correct detection performance and state success motivation predicted sensitivity, but not false alarm performance, response bias, or global workload. We conclude with a discussion of the theoretical and practical applications of this research.