Effects of Noise and Response Complexity upon Vigilance Performance

Visual vigilance performance was investigated with respect to environmental stimulation (90 db, 1000 cps noise) and intra-organismic stimulation (simple vs complex response). 140 Ss monitoring a display for 1 hr. under 1 of 2 noise types were instructed either to press a button upon detection of aperiodic signals (simple response) or to perform also a checklist operation subsequent to the signal detection (complex response). Significant correct detection differences occurred between response groups with complex groups showing higher performance (p < .05). Differences in correct detection were obtained for noise conditions (for continuous, M = 83%; for intermittent, M = 78.5%). Results were evaluated in terms of the activation hypothesis.