Objects and their locations in exogenous cuing

Anatomical, physiological, and behavioral studies provide support for separ ate object- and location-based components of visual attention. Although stu dies of object-based components have usually involved voluntary attention, more recent evidence has suggested that objects may play an independent rol e in reflexive exogenous orienting, at least at long stimulus onset asynchr onies (SOAs). In the present experiments, the role of objects in reflexive attentional orienting was investigated by developing a task in which locati on and object cuing could be separately examined for both short and long SO As. Typical location cuing effects were obtained, indicating facilitation a t short cue-target intervals and inhibition of return (IOR) at longer inter vals. In contrast, object cuing resulted in facilitation for cued objects a t long cue-target intervals and no object-based IOR. Interestingly, object cuing primarily affected targets at cued locations, and not those at uncued locations. Together, the experiments examine the interactive nature of obj ects and locations in exogenous orienting and seem most consistent with a l ocation-mediated view of object-based orienting.