FIGURE 1.

Audio-visual detection task. In the unimodal visual-attention condition (top row), participants fixated the centre of the screen and two objects appeared. Attention was reset towards one of the objects using a brief attentional reset event (AR), presentation of 4 dots for 33 ms. Subsequently, a contrast change (33 ms) occurred after 0.3–1.2 s, either within the same object that was cued or within the object on the opposite side (with equal probability). In the unimodal auditory-attention condition (second row) participants also fixated on the screen, but instead of visual objects, they were presented with Brownian noise in both ears. Here, the AR was a salient click in one ear, and the target consisted of a faint beep either in the ipsilateral or the contralateral ear. In bimodal trials (third and fourth row), visual objects and Brownian noise were presented simultaneously. Visual and auditory AR events were always spatially congruent. The target appeared in only one modality (i.e., either a contrast change or a beep) and participants reported, via button press, whether the target appeared on the left or right. Participants’ performance was held constant at ~66% by increasing or decreasing target saliency based on their modality-specific performance over the last six trials