Reversing the Vigilance Decrement: Effects of a Late Modality Switch on Detection Performance

When people monitor rare signals for sustained periods, detection performance declines over time (vigilance decrement). In applied settings this decline can lead to missed critical signals. Prior research examined whether changing display modalities would improve detection after a vigilance decrement, but results were inconsistent, possibly because auditory and visual tasks differed in difficulty and stimulus intensity, a confound eliminated in the current study. Discrimination difficulty and intensity were matched between visual and auditory modalities for each participant before a 50-min vigil encompassing five 10-min periods. Participants either remained in the same modality throughout or switched to the alternative modality in the final period. Hit rate declined across the first four periods. However, hit rate improved from Period 4 to Period 5 for participants who switched modalities, but not for those who did not. These findings suggest that a late modality change may restore detection performance after a vigilance decrement.