Vigilance as a Function of Stimulus Variety and Response Complexity

Abstract

A vigilance experiment was conducted in which subjects monitored a multistimulus source display for a 100-min period. The purpose of the experiment was to determine the effects on vigilance performance of random insertion of artificial signals and complexity of required response. Several measures of task performance were analyzed: average time to detect real signals; intrasubject variability in detection time; percentage of real signals detected; number of errors made under different conditions of response complexity; and occurrence of movements extraneous to task requirements. Results indicated that the introduction of artificial signals enhanced vigilance performance by reducing the variability in detection response times and by increasing percentage of signals detected. There was no significant decrement in response times over the task session. Introduction of a complex response requirement into the task did not result in improved vigilance performance, as predicted. Results are discussed in terms of a single “construct” of vigilance and in terms of implications for applied situations.