Noise and Vigilance: An Evaluative Review

Abstract

The literature on the effects of noise on monitoring performance shows a disappointing lack of consistency in results. The hypothesis of the present study was that task classification in terms of demands made on the observer should reconcile conflicting findings so that generalizations could be made. Therefore, a study was made of the effects of intermittent or variable noise on vigilance experiments with similar task demands. Twenty-one sensory vigilance studies, selected from 98 visual performance experiments, were analyzed in detail. It appeared that, even when studies possess similar task characteristics, they are hard to compare due to the many types and varieties of the noise variables involved and the measures of performance used. Contradictory results remain. It was concluded that we know nothing about the effects of variable noise on sustained attention, despite the importance of this kind of noise for everyday life. Using this detailed analysis as an illustration, it was suggested that disparate task definitions contribute to variable or inconsistent results in vigilance, and that it does not make sense to search for the effect of independent variables on “vigilance.” The usefulness of future reviews of “noise and vigilance,” as well as of “the effects of noise,” and the results of “vigilance tasks” were questioned.