To test these possibilities, the performance of animals in localizing and detecting spatiotemporally concordant visual and auditory stimuli was examined when these stimuli were presented individually (visual or auditory) or in cross-modal (visual–auditory) and within-modal (visual–visual, auditory–auditory) combinations. Performance enhancements proved to be far greater for combinations of cross-modal than within-modal stimuli and support the idea that the behavioral products derived from multisensory integration are not attributable to simple target redundancy.