A Signal Detection Analysis of Visuo-Tactile Dual-Tasking Performance Under Varying Temporal Task Loads

This study examined whether tactile detection reduces dual-task costs compared to visual detection when paired with a visual tracking task, and whether this advantage persists as temporal task load increases. Thirty-eight participants completed a visual tracking task and a detection task concurrently. The detection task was presented either visually or tactually, and temporal task load was manipulated by varying the stimulus presentation rate. Performance was analyzed using signal detection theory measures to determine whether differences between visual and tactile detection reflected changes in perceptual sensitivity, response bias, or both. Tactile detection produced smaller dual-task costs than visual detection across hit rate, false alarm rate, sensitivity, and response bias. Critically, tactile detection better preserved sensitivity under dual-task conditions, suggesting reduced perceptual competition with the visual tracking task. However, higher temporal load still degraded performance in the tactile condition. These findings support multimodal interface design while highlighting limits of modality diversification.