The Effect of Auditory Display Configuration and Physical Load on Message Intelligibility for the Dismounted Soldier

Abstract

The purpose of this study was to determine the extent to which different types of audio display technology affected the ability of the physically active, load-carrying dismounted soldier to understand and respond to multiple radio communications in the battlefield. Independent variables were different types of auditory display configuration (existing monaural and spatial audio), number of simultaneous talkers in each simulated radio message (two, three, or four), and soldier rucksack load (22 kg or 33 kg). The dependent variables included the response time and number of accurate responses to the radio messages, soldier ratings of mental workload, and soldier physiological workload. Subjects were nine (9) male Marine Corps Infantry personnel and three (3) male Army Infantry personnel. Results indicated that spatial auditory displays enabled soldiers to identify a significantly greater number of simulated radio communications, and respond to these communications more quickly. Message response time increased and identification accuracy decreased as the number of simultaneous talkers increased. Rucksack weight was a predominant variable in physical and mental workload. Soldiers showed significantly greater physiological energy expenditure and significantly greater mental workload when they carried the heavier rucksack. The results indicated that whatever the load carried by the soldier, the speed and accuracy of understanding and responding to multiple radio communications were enhanced by presentation in different spatial locations.