PROCEEDINGS of the HUMAN FACTORS SOCIETY 36th ANNUAL MEETING-1992 A PILOT STUDY ON THE PERCEIVED URGENCY OF MULTITONE AND FREQUENCY-MODULATED WARNING SIGNALS

In some environments, there is a serious mismatch between the perceived (psychoacoustic) urgency of a warning and its situational urgency. This pilot study investigated effect of pulse format, pulse duration, and time between pulses on the perceived urgency of warning signals. The intent was to determine the best combination of variables and levels of variables to use in a formal study on the perceived urgency of warning signals. The results indicated that only pulse format and time between pulses were significant. Subjects rated sequential pulses as being less urgent than any other format. Signals with shorter inter-pulse intervals were rated as significantly more urgent. Pulse format and time between pulses were determined to be variables which should be used in future research. BACKGROUND Auditory warning signals have found their way into many environments. When designed correctly, they can improve performance and reduce accidents. However, in some environments, there is a serious mismatch between the perceived (psychoacoustic) urgency of a warning (the implicit urgency as a function of its sound parameters), and its situational urgency (the degree of urgency associated with the situation itself) (Edworthy, 1991). This mismatch has been demonstrated in aircraft (Patterson, 1982) and in operating and recovery rooms i