Abstract
The contribution of object-based representations to attentional guidance has almost exclusively been investigated within the framework of top-down attentional guidance. It has been demonstrated that object-based representations guide top-down attentional selection as measured by object-based effects. Little is known, however, regarding the contribution of object-based representations to bottom-up, or stimulus driven, attentional control. In the present set of three experiments we investigated whether the extent of attentional capture is in fact modulated by object-based representations. Participants viewed a central rapid serial visual presentation (RSVP) stream in which a target letter was defined by a specific color (e.g., red). The RSVP stream was superimposed onto a set of three objects (a cross like configuration). On critical trials, irrelevant color singleton and three neutral distractors appeared in the periphery. On half of the trials the irrelevant colored singleton appeared on the same object as the central target, while on the other half of the trials the irrelevant colored singleton appeared on a different object. We replicated the canonical contingent attentional capture finding such that peripheral singleton produced a decrement in central target identification that was contingent on the match between the singleton color and the target color. We also observed that the magnitude of attentional capture was modulated by whether the irrelevant color singleton appeared on the same or different object (i.e., object-based effect). Additionally, it was observed that the extent to which object-based representations modulated attentional capture depended upon the search mode of the observer (i.e., singleton search mode or feature search mode). These results suggest that object-based representation guide bottom-up as well as top-down attentional control, as well as provide further constraints on the mechanisms of object-based selection.