The effects of signal salience and caffeine on performance, workload, and stress in an abbreviated vigilance task

In 2 experiments, a 12-min computerized vigilance task was demonstrated to reproduce the vigilance decrement, high workload (NASA-TLX), and stressful character (Dundee Stress State Questionnaire) of vigilance tasks lasting 30 min or more. In Experiment 1, the abbreviated task was also shown to dupli cate the signal salience effect, a major finding associated with long-durat ion vigilance tasks. Moreover, Experiment 2 showed that performance on the abbreviated task can be enhanced by caffeine - a drug that benefits long-du ration tasks. This enhancement effect was limited to performance, however, suggesting that caffeine influences factors that control signal detection b ut not those that control task-induced stress. The results parallel those o btained with long-duration tasks and support a resource-depletion model of the vigilance decrement. The abbreviated task might be useful in situations in which long-duration tasks are precluded (e.g., performance assessment b atteries, neuropsychological testing, and brain imaging).