The effects of occlusion and past experience on the allocation of object-based attention.

There is considerable evidence indicating that cuing a specific portion of an object results in the entire object's being attended to. In the present study, we examined whether previous experience with an object could halt perceptual (i.e., amodal) completion. In Experiment 1, two parallel rectangles were initially displayed, and then the middle portions of these objects were occluded. Attentional cuing effects were found for both discrete portions of the completed rectangles. In the final two experiments, four discrete objects were initially displayed, followed by the same occluder as that used in the first experiment. The appearance of the occluder (500 msec before the cue in Experiment 2,100 msec before the cue in Experiment 3) allowed the four discrete objects to be completed into two rectangles. Attentional cuing effects were found for the completed rectangles in both experiments, indicating that previous experience was not sufficient to halt the amodal completion of objects.