Abstract
Object-based effects of visual attention were reported by Egly Driver and Rafal (1994) using a modified Posner cueing paradigm. In a two-rectangle (i.e., “object”) display, they cued one end of one rectangle on each trial. Targets were most likely to appear at the cued location. In invalid-within object conditions, the target appeared in the same rectangle as the cue, but at the opposite end. In invalid-between object conditions, the target appeared in the rectangle opposite the cue. Importantly, invalid targets appeared the same distance away from the cue in both within and between conditions, holding space constant. When comparing the two invalid conditions, within-rectangle targets were detected faster than between-rectangle targets; RTs showed object-based facilitation. In a set of similar experiments, we replicated these effects when the shapes were perceived as objects (wholes) but not as “holes”. We used stereoscopic goggles to provide sufficient depth cues for the perception of “holes” and objects. To confirm that the disappearance of the object-based effect is due to the “holes” grouping with the larger background region and not simply an effect of depth, we examined object-based effects in holes under conditions in which the background region was either split or connected. The data supported our hypothesis: when the background region was split, the shapes perceived as holes were again individuated, and elicited object-based effects. Specifically, we found significant object-based effects in the split/holes, split/objects, and the connected/objects condition, but not in the connected/holes condition, replicating and expanding our previous findings. The results provide further evidence that attention and perceptual organization interact.