The Effect of Type of Task, Degree of Integration, and Modality on the Performance of Concurrent Tasks

Abstract

Sixteen subjects performed a continuous, visual-manual, tracking task while simultaneously performing a visual-manual or auditory speech discrete task. The discrete tasks were either integrated with or not integrated with the continuous task and involved either verbal or spatial central processing. Tracking accuracy, discrete task response latency, and discrete task accuracy were measured. The major findings were that when a discrete task involving verbal central processing was performed concurrently with a visual-manual tracking task, better performance was obtained on both the discrete task and the tracking task when the discrete task was performed with auditory input and speech response, rather than with visual input and manual response. However when the discrete task involved spatial processing codes, use of the auditory-speech modalities resulted in no advantage on the discrete task and the advantage on the tracking task was diminished. It was also found that tracking performance was better when the tracking and discrete tasks were integrated. This was true of discrete task performance only with spatial codes and the auditory-speech modalities. Findings suggest that discrete task accuracy, rather than tracking accuracy, may be the area in which the effects of mental workload are of greatest practical significance.