Tank Crew Performance: Effects of Speech Intelligibility on Target Acquisition and Subjective Workload Assessment

Abstract

Thirty tank crews were tested in the Ft. Knox COFT tank simulator. The COFT simulator is a gunnery training facility. The crew's task was to shoot specified enemy targets. Each crew consisted of a tank commander and a gunner. The commander told the gunner, via an intercom system, which enemy object was the next target. Performance and subjective workload were measured as a function of the speech intelligibility transmitted by the intercom system. Five levels of intelligibility were tested. The measures of operational effectiveness were the number of targets correctly fired upon and the gunner's latency. Subjective workload was measured using the Subjective Workload Assessment Technique (SWAT). Gunner performance and subjective workload covaried across intelligibility levels. Performance was not significantly affected until intelligibility levels fell to 50%. However, SWAT ratings increased linearly with decreasing intelligibility level.