Auditory Displays: If They Are So Useful, Why Are They Turned Off?

摘要

Pilots often turn off the auditory displays which are provided to improve their performance (Weiner, 1977; Veitengruber, Boucek, & Smith, 1977). The intensity of the auditory display is often cited as a possible cause of this behavior (Cooper, 1977). However, the processing of the additional information is a concurrent task demand which may increase subjective workload (Wickens & Yeh, 1983; McCloy, Derrick, & Wickens, 1983). Pilots may attempt to reduce subjective workload at the expense of performance by turning off the auditory display. Forty undergraduate males performed a visual search task. Three conditions: auditory display on, auditory display off, and subject's choice were run in combination with nine levels of visual display load. The auditory display, a 4000 Hz tone with a between-subject intensity of 60 dB(A), 70 dB(A), 80 dB(A), and 90 dB(A), indicated that the target letter was in the lower half of the search area. NASA-TLX (Task Load Index) was used to measure the subjective workload of the subjects after each block of trials (Hart & Staveland, 1988). A non-monotonic relationship was found between auditory display intensity and auditory display usage. Evidence was found that the auditory display increased some aspects of subjective workload- physical demands and frustration. Furthermore, there was a dissociation of performance and subjective workload in the manner predicted by Wickens & Yeh (1983). The implications of these results for display design are discussed.