Combating Cry Wolf: The Effects of Urgency and Reliability on Reactions to Verbal Alarms

Previous research has shown that manipulating the acoustic features of auditory alarms can alter their perceived urgency. Research has shown that increasing the perceived urgency of nonverbal auditory alarms can significantly improve response degradation due to alarm mistrust. This study determined if the effect of perceived urgency on response performance also applies to verbal alarm systems. Forty graduate and undergraduate psychology students from Old Dominion University were sampled for this study. The experimenter examined participant performance during four experimental sessions. After each session a twelve-item questionnaire designed to measure participants'rust in the alarm system was administered. Two conditions of urgency (urgent and nonurgent) were manipulated within the study by altering alarm acoustic parameters using the sound editing program Pratt TM. The other independent variable, alarm system reliability, was also manipulated within groups. Participants' performances on an alarm reaction task and a multi attribution task battery (MAT), and responses to the trust questionnaire were recorded and analyzed. A 2x2 ANOVA was calculated to analyze the effects of alarm system reliability and perceived urgency on a composite measure of trust. Also, a 2x2 mixed MANOVA was calculated to examine the effects of alarm system reliability and perceived urgency on reaction time, and two 2x2 mixed ANOVAs were computed for alarm response frequency and appropriateness. As predicted, participants trusted the high reliability system significantly more than the low reliability system. Also, the verbal alarm stimuli perceived as urgent improved alarm reaction appropriateness. Therefore, performance degradation due to the Cry Wolf Effect was moderated by alarm urgency. Alarm designers can use these findings to design verbal alarm systems that evoke more appropriate responses from users.