Supramodal and modality-specific mechanisms for stimulus-driven shifts of auditory and visual attention.

Two experiments are described in which visual and/or auditory location precues preceded visual or auditory targets. Observers were required to judge the location of the targets. Conditions were such that involuntary, stimulus-driven attention shifts were the only ones likely to occur and give rise to cueing effects. It was found that visual precues affected response time to localize both visual targets and auditory targets but auditory precues affected only the time to localize auditory targets. Moreover, when visual and auditory cues conflicted, visual cues dominated in the visual task but were dominated by auditory cues in the auditory task. These results imply that involuntary stimulus-driven attention shifts might be controlled by a modality-specific mechanism for visual tasks, whereas stimulus-driven shifts of auditory attention are controlled by a supramodal mechanism. This asymmetry in attention control is consistent with the idea that attentional dominance in a multimodal experimental task depends on the relative performance possible in the modalities involved; in this case visual localization is more precise than auditory and so auditory cues may be ineffective in cueing visual location, while visual cues are effective in both modalities.