Maintainance of vigilance in an auditory monitoring task.

4 levels of critical signal frequency and 3 levels of task complexity were compared for their effect on vigilance in an auditory monitoring task. Proportionate omission errors increased as the frequency of signals decreased, as expected. However, complexity (defined as the number of categories of critical signals) had an unexpected effect in that relatively poor performance occurred with increased complexity. The results were interpreted as suggesting caution in the use of artificial signals as a means to overcome loss of vigilance in monitoring tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)