Figure 1

Schematic illustration of the trial sequence.
First, in each trial, a color cue informed participants to direct attention to one of two upcoming brief intensity changes during the audio-visual stimulation. Next, a complex sound and a circular drifting grating were presented. Two simultaneous 300 ms changes in sound volume and visual contrast occurred during the 2500 ms stimulation. After stimulation offset, participants indicated whether for the attended interval the two modalities changed in the same direction (congruent) or in different directions (incongruent). In this example both first and second changes are congruent. In the experiment increases and decreases in both modalities varied independently.