The Effect of Sonification Pulse Rate and System Reliability on Perceived Workload Urgency Trust and Monitoring Performance

The purpose of the current study was to examine the effect of sonification pulse rate and system reliability on subjective workload, urgency, trust, and monitoring performance of a dual task simulation of patient monitoring. Fifty-eight students performed a compensatory tracking and resource management task while simultaneously engaging in a patient monitoring task. Sonification pulse rate contained three levels (40ppm, 60ppm, 80ppm) and was manipulated within groups by varying the inter-pulse interval of the auditory signal. System reliability contained two levels (40%, 60%) and was manipulated between groups by varying the number of true and false problems presented by the sonification system. Perceived subjective workload, trust, and urgency were examined via questionnaires. Monitoring performance accuracy was examined using two models of SignaI Detection Theory (SDT). A series of 2 x 3 Mixed ANOVA's were used to analyze subjective and performance data. Results mainly supported our hypotheses. Specifically, results demonstrate significant effects of pulse rate and reliability on subjective workload, trust, urgency, and monitoring performance. Overall, setting the sonification to 60 ppm relative to 40ppm and 80ppm resulted in lower workload ratings, higher trust ratings, and moderate urgency ratings. Furthermore, participants made timely responses and increased decision accuracy, without increasing reaction responsiveness, when the sonification pulse rate was set to 60 ppm. These results are important for sonification design, and suggest that setting sonification pulse rate to 60 ppm can maximize monitoring accuracy without overburdening the operator. Areas of future research and practical applications are discussed.