Several studies found cross-modal cueing can enhance perceptual
tasks; visual stimulus, for example, can be better detected with auditory cue than without it. Most studies, however, focused on a target within foveal or peripheral visual field (e.g., 20°–50° eccentricity). Neurological and behavioral studies showed auditory can complement visual perception in the periphery, but such cross-modal cueing in the extreme-periphery has been unexplored. In the present study, participants detected a dot appeared randomly in either left/right extreme-periphery (from 60°to 90°, with 5° distance). In a half of the trials, the dot was presented with a simultaneous beep as an auditory cue. The results counterintuitively indicated that auditory cue significantly decreased the visual detection in the extreme-periphery. Further pilot study implied auditory cue may be more reckoned on with widespread visual attention and produced false alarms, resulting decreased sensitivity in the extreme-periphery