How visual and auditory task loads differently impair the advantage of multimodal warnings

Multimodal warnings elicit faster response times than unisensory warnings in cockpits. However, how visual and auditory task demands affect the detection of multimodal warnings remains unclear. This study recruited 30 pilots and 30 control participants to complete a warning response task and an aviation visual or auditory task. The race model inequality analysis indicated that the multisensory enhancement effect decreased as the load increased. The analysis of variance indicated an interaction effect among modality, load level, and task type on response times. Results suggested that demanding tasks may affect the detection of multimodal warnings more substantially than that of unisensory warnings within the same modality. The slowing of response times to multimodal warnings may be driven by the more load-sensitive sensory component. The findings were consistent across groups. This study provides practical implications for multimodal warning design and theoretical insights into multimodal processing.