The involvement of bottom-up saliency processing in endogenous inhibition of return.

Participants are faster at detecting a visual target when it appears at a cued, as compared with an uncued, location. In general, a reversal of this cost-benefit pattern is observed after exogenous cuing when the cue-target interval exceeds approximately 250 ms (inhibition of return [IOR]), and not after endogenous cuing. We suggest that, usually, no IOR is found with endogenous cues because no bottom-up saliency-based orienting processes are claimed. Therefore, we developed an endogenous feature-based split-cue task to allow for endogenous saliency-based orienting. IOR was observed in the saliency-driven endogenous cuing condition, and not in the control condition that prevented saliency-based orienting. These results suggest that usage of saliency-based orienting processes in either endogenous or exogenous orienting warrants the appearance of IOR.