The Effects of Workload Presented via Visual and Auditory Displays on Soldier Shooting and Secondary Task Performance

Report No. ARL-TR-4224
Authors: David R. Scribner, Patrick H. Wiley, William H. Harper, and Troy D. Kelley
Date/Pages: August 2007; 45 pages
Abstract: The dismounted warrior will be enabled with dominant situational understanding. The information that a Soldier needs will be provided through a wearable command, control, communication, computing, and intelligence system that will provide enhanced communication, navigation, weapon-sensor connectivity, and other data access features. If such a system is not designed to allow optimal Soldier-system performance, then it is conceivable that the mental overburden could result in decreased Soldier survivability and lethality. This study was performed in the dismounted infantry survivability and lethality test bed shooting simulator facility of the U.S. Army Research Laboratory. The present study proposed the examination of the presentation of mental workload via a single auditory and four visual display conditions: 1) a forearm-mounted personal data assistant display (FMD), 2) a helmet-mounted display (HMD), 3) an FMD with an auditory alert cue, and 4) an HMD with an auditory alert cue. The auditory alert cue informed the Soldier that a new piece of information appeared on his screen. There was also a no-workload shooting condition. Soldiers were asked to complete arithmetic problems while shooting a friend-or-foe scenario. Additionally, the study examined the ability of Soldiers or Marines to maintain the primary task of shooting pop-up friend-or-foe scenarios while performing secondary tasks of mathematical problem solving and situational awareness (SA) memory recall tasks. Finally, the study examined the effect of cognitive workload levels upon the ability of Soldiers to correctly make shoot/do-not-shoot decisions in a friendor- foe target environment. Participants were 12 U.S. Army Soldiers. They were all military occupational specialty 11B (infantry) with ages ranging from 20 to 27 years old and a mean age of 24.6 years. The shooting task consisted of a 24-target pop-up scenario that used 50% friendly (brown target) and 50% enemy (black target) E-type silhouette targets. Ranges consisted of 75-, 100-, 150-, 200-, 250-, and 300- meter targets. All target presentations were randomized for each 2-minute shooting trial. Target exposure time was 3 seconds. Soldiers were in a foxhole-supported kneeling position for all trials. The M16A2 with iron sights was used. Dependent variables included (primary task) shooting performance (enemy targets hit, errors) and secondary task (math) completion rates, subjective workload assessment technique workload ratings, and subjective rating of events general stress ratings. Subjects were instructed to maintain primary task (shooting) performance through all trials. An analysis of variance analyses revealed significant differences for shooting performance and math task completion rates for certain display configurations.
Distribution: Approved for public release
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Last Update / Reviewed: August 1, 2007