Processing Demands, Training, and the Vigilance Decrement

Abstract

Two possible sources of vigilance decrement are inadequate training of operators and taxing information-processing demands. This study attempted to compensate for both of these sources. Although compensation for training was effective, processing demands may have been set too high, as detection sensitivity declined. This result suggests that an event rate much less than the current threshold of 24/min is necessary to stabilize sensitivity. Response latency increased progressively during the task and was greater for “unsure” as compared with “sure” decisions. Consistent with an adaptation-level hypothesis, reduced sensitivity was compensated by a general negative shift in response bias. This adaptive process may account for the absence in this study of the usual form of vigilance decrement: a positive shift in bias, which reduces both detection and false-alarm scores.