Processes of the cross-modal spread of attention within a multisensory
object. As illustrated here, attention is focused on the visual modality to the
right side by endogenous attentional selectivity. When the visual and auditory
stimuli are presented simultaneously, they are processed in a multisensory
manner. After low- and high-level multisensory processing, these stimuli are
integrated into a coherent multisensory object. Within this multisensory object,
attention can spread from the attended visual stimuli to the ignored auditory
stimuli across modalities and locations, which occurs automatically. Moreover,
the process of attentional spread across modalities and space involves dual
mechanisms (Fiebelkorn et al., 2010). One
mechanism is the stimulus-driven spread of attention, which is affected by
spatial or temporal links between the auditory and visual stimuli (Donohue et al., 2011). The other mechanism
is the representation-driven spread of attention, which is modulated by
congruency when the multisensory stimuli must be checked in terms of matching or
congruency (Zimmer et al., 2010a; Zimmer et al., 2010b). After these
processing stages, the ignored auditory stimulus acquires attention from the
attended visual stimuli. This entire process consists of endogenous attentional
selectivity and the exogenous cross-modal spread of attention.