Detection and Identification of Simultaneous Communications in a Simulated Flying Task

Operators of military flight vehicles are often required to attend to more than one source of communications signal. Previous research has shown that the intelligibility of a speech message in a background of speech distractors is improved if the signals are presented using a 3-dimensional (3-d) audio display rather than the traditional diotic configuration. However, whether infrequent target messages (e.g., callsigns) are more reliably detected in a continuous monitoring task with high temporal uncertainty when using a 3-d audio display has not been examined. This study examined participants' ability to detect a target callsign and identify a colour/number combination associated with it while engaged in a 20-minute, simulated formation-flying task. Participants were required to monitor 5 communications channels in each of which messages were presented at random intervals. (On average, 2.4 channels were simultaneously active.) Thirty targets were presented over the 20-minute period. There were three audio display conditions: diotic, all channels in front, and channels separated in azimuth (3-d). Detection of target callsigns was significantly higher in the 3-d condition compared to the other conditions. Detections and false alarms were combined to calculate sensitivity and criterion measures using signal detection theory. Sensitivity was significantly higher in the 3-d condition compared with the other conditions, but there were no differences in criterion. Also, consistent with previous results, correct identification of the target number/colour combination was significantly higher in the 3-d condition compared with the other conditions.