Updating the dual-mechanism model for cross-sensory attentional spreading: The influence of space-based visual selective attention.

Selective attention to visual stimuli can spread cross-modally to task-irrelevant auditory stimuli through either the stimulus-driven binding mechanism or the representation-driven priming mechanism. The stimulus-driven attentional spreading occurs whenever a task-irrelevant sound is delivered simultaneously with a spatially attended visual stimulus, whereas the representation-driven attentional spreading occurs only when the object representation of the sound is congruent with that of the to-be-attended visual object. The current study recorded event-related potentials in a space-selective visual object-recognition task to examine the exact roles of space-based visual selective attention in both the stimulus-driven and representation-driven cross-modal attentional spreading, which remain controversial in the literature. Our results yielded that the representation-driven auditory Nd component (200-400 ms after sound onset) did not differ according to whether the peripheral visual representations of audiovisual target objects were spatially attended or not, but was decreased when the auditory representations of target objects were presented alone. In contrast, the stimulus-driven auditory Nd component (200-300 ms) was decreased but still prominent when the peripheral visual constituents of audiovisual nontarget objects were spatially unattended. These findings demonstrate not only that the representation-driven attentional spreading is independent of space-based visual selective attention and benefits in an all-or-nothing manner from object-based visual selection for actually presented visual representations of target objects, but also that although the stimulus-driven attentional spreading is modulated by space-based visual selective attention, attending to visual modality per se is more likely to be the endogenous determinant of the stimulus-driven attentional spreading.