Attentional Resource Allocation Across Vision and Audition: No Single Factor for Resource Sharing

When we attend to two concurrent tasks, our performance often deteriorates because of limited attentional resources. However, it remains controversial to what extent attentional resources are supramodal or modality-specific. This study investigated the effect of sustained concentration on audiovisual interference using object-based attention tasks. In Study 1, participants engaged in dual-tasks consisting of a luminance change detection task (visual) and a vowel detection task (visual/auditory). By comparing performance in unimodal and bimodal dual-tasks, we observed a trade-off between vision and audition, suggesting at least partial recruitment of supramodal attentional resources. In Study 2, participants engaged in dual-tasks consisting of a pitch change detection task and the same vowel detection task as in Study 1. We observed little interference in the bimodal dual-task but significant interference in the unimodal dual-task. These results suggest that it is difficult to determine the recruited attentional resources from a single perspective.