Effect of Task Modality on Dual-Task Performance, Response Time, and Ratings of Operator Workload

Abstract

The purpose of this study was to use established measures of attentional reserve capacity to test for the existence of tactile-specific resources in the context of Wickens’ (1984, 2002) Multiple Resource Theory. Participants performed a primary counting task in the tactile modality and were presented with a concurrent secondary attention task in the visual, auditory, and tactile modalities. The data indicate a significant difference in performance based on whether the dual-task conditions were performed crossmodally or unimodally, in terms of percent correct and response time to target stimuli. Specifically, participants performed significantly worse in tactile-tactile dual-task conditions, suggesting performance was degraded as a function of resource depletion. Furthermore, participants rated the unimodal dual-task conditions as significantly harder, using a subjective workload rating, than either of the dual-task crossmodal conditions, or the single task condition. The results suggest that task interference was a function of resource limitation rather than structural interference, providing direct empirical evidence supporting the inclusion of tactile resources in Wickens’ Multiple Resource Theory.