Signal Complexity, Response Complexity, and Signal Specification in Vigilance

Abstract

Sixty-four subjects served in a 50-min auditory monitoring task. Task complexity was examined with regard to both signal and response demands in an effort to determine variance contributing to each of these variables. Signals were presented at a mean rate of one per min, and no intersignal interval was greater than 2 min. Results showed that signal demands were of greater importance in affecting performance than were post-detection response contingencies. Statistically significant differences were obtained between groups monitoring only one signal and those monitoring any of seven signals, with the former condition exhibiting better performance over time. Groups in which signals were left unspecified exhibited lower detection percentages and higher false alarm rates than conditions in which signals were specified. No statistical differences between simple and complex response conditions were observed. Application of the present findings to applied environments is discussed.