Effects of instantaneous object input and past experience on object-based attention.

Evidence for object-based attention typically comes from studies using displays with unchanged objects, and no consensus has yet been reached as to whether the object effect would be altered by changing object displays or having seen this change across-trials. We examined this by using modifications of the double-rectangle cuing paradigm of Egly et al. [Egly, R., Driver, J., & Rafal, R. D. (1994). Shifting visual attention between objects and locations: Evidence from normal and parietal lesion subjects. Journal of Experimental Psychology: General, 123, 161-177], and our results, when the objects remained unchanging, replicated the original object effect. However, no object effect was found when the rectangles disappeared from view in the last (target) frame. This was true regardless of the likelihood of the rectangles disappearing, indicating the importance of instantaneous object inputs for object-based attention. The across-trial experience of seeing a different object (boomerang), however, was found to influence the object effect when the cued rectangles persisted throughout the trial. Unlike previous studies, which emphasize one or the other, we demonstrate clearly that instantaneous object inputs and past experience interact to determine the way attention selects objects.