Investigation on the effects of presentation modality for spatial signals on human performance using a dual task paradigm

A dual task was designed to involve a tracking mission with various tracking speeds and a spatial compatibility task with various signal-key mappings and presentation modalities. This dual task was used to investigate the effects of workload and resource competition in distinct parts of the dual-task process. The results demonstrated that increasing the tracking speed adversely affected the tracking performance but led to positive arousal to the secondary discrete response task. Visual spatial signals gave the shortest reaction time due to the optimal time-sharing of the visual resources in the focal and ambient channels. Compared with visual spatial signals, spatial signals of auditory and tactile modalities did not lead to an improved performance because of their cross-modality nature. These findings provided practical design guidelines for dual tasks in which the operators need to complete a continuous monitoring task visually and elicit timely and accurate responses to spatial information.