The effect of attention on the illusory capture of motion in bimodal stimuli.

A large body of work now exists that demonstrates the interaction between different sensory modalities when they are integrated into a single coherent percept. Yet, it is not yet clear whether attention plays a critical role in such crossmodal interactions. We investigated the effect of attention on the crossmodal integration of apparent motion signals using the crossmodal dynamic capture paradigm. The stimuli were bimodal apparent motion streams consisting of audio-visual, visual-tactile, or audio-tactile signals. The task was to indicate the direction of motion in one of the modalities, called the target modality, that could be congruent or incongruent with the direction of the second motion stream, called the distractor modality. The influence of the distractor modality on participants' response accuracy, called crossmodal capture, was assessed across three conditions of attentional manipulation. We found that attention does have an effect on how the motion signals are combined across modalities, but only when the susceptibility for capture between the two signals are comparable.