Pii: S1388-2457(99)00052-8

Objectives: An event-related brain potential (ERP) study investigated whether spatially selective processing in vision and audition is controlled by a single supramodal system or by independent modality-speci®c systems. Methods: Event-related brain potentials were recorded in response to visual and auditory stimuli at attended and unattended locations. In the `Attend Same' condition, attention was directed to a single location in both modalities, while in the `Attend Opposite' condition, visual and auditory attention had to be directed into opposite directions. Results: Sensory-speci®c effects of attention on visual and auditory ERPs re ̄ecting attentional modulations of perceptual processing were obtained in the `Attend Same' condition, but not the `Attend Opposite' condition. Beyond 200 ms post-stimulus, attentional ERP effects were also found in the `Attend Opposite' condition. Conclusion: Results are inconsistent with the view that spatially selective processing is controlled by independent modality-speci®c systems. Effects of spatial attention on visual and auditory perceptual processing are closely linked, suggesting the existence of a supramodal attentional control system. At post-perceptual levels, attentional control may be more ̄exible. q 1999 Elsevier Science Ireland Ltd. All