Auditory Monitoring of up to Eight Simultaneous Sources

The present research examined visual and auditory monitoring of independent, concurrent sources. Subjects monitored from one to eight concurrent visual indicators for the occurrence of a “launch” event. Five between-groups conditions were studied: a visual-only group, plus four audiovisual groups that differed in the amount of information provided over the auditory channel. Accuracy scores were very high for all groups. Response times showed an overall increase with display density (number of concurrent sources). A significant group x density interaction revealed an advantage of one of the audiovisual conditions compared to the visual-only group at moderate density levels (5 or 6 concurrent sources), but not at lower or higher density levels. This finding probably indicates the value of an auditory signal to reduce visual search time.