Inhibition of return to successively cued spatial locations

Inhibition of return refers to a bias against returning attention to a location that has been recently attended. Experiments are reported that examined inhibition of return to multiple exogenously cued spatial locations. When 2 peripheral locations were cued in succession, inhibition was found for only the 1 most recently cued location. In addition, more inhibition occurred at the location of the most recent cue if the earlier cue had also been presented there, as compared with an earlier cue at a different location. Thus, the magnitude of the inhibition for a location appears to depend on the effectiveness of the attentional cue to that location. Other results suggest that candidate locations for inhibition are displaced by subsequent cues—they do not simply decay. The results provide an initial framework within which to study inhibition of return to multiple spatial locations. During everyday life, people must often locate visible objects. Tasks such as finding the pen on one's clean desktop, meeting a friend at a quiet street corner, or finding one's car in an otherwise empty parking lot can all be accomplished relatively easily. However, considerable dif-ficulty might be encountered when the desk is cluttered, the street corner is busy, or the lot is filled with other cars. In those situations, it may be necessary to move one's attention from location to location to find the target object. Such searches are often accomplished by making eye or head movements, although many searches must also involve co-vert movements of attention—without any eye or head movements. Visual searches such as these (either overt or covert) would obviously benefit from a mechanism that prevented one from re-searching a previously inspected location. Indeed, such a mechanism has been identified and has been termed inhibition of return, referring to the fact that attention is sometimes inhibited in returning to a pre-viously attended (i.e., inspected) location (Posner & Cohen