Soetens, E. , Henderickx, D. , Maetens, K. & Deroost, N.
Cognitive Psychology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
People are faster at detecting a visual target when it appears at a cued, as compared to an uncued location. With exogenous cues, a reversal of this cost-benefit pattern generally occurs when the cue-target interval exceeds approximately 250 ms. This pattern is known as ‘Inhibition of Return’ (IOR), and is usually not obtained with endogenous cues. We suggest that no IOR is found with endogenous cues, because most volitional attention shifts act upon higher processing levels, while the IOR- mechanism acts only upon bottom-up saliency-based orienting processes. To demonstrate this, participants had to orient to one out of two differently coloured peripheral cues, indicated by a (preceding) central cue. With this method, endogenous orienting could act upon low-level saliency processes when participants had sufficient time between central and peripheral cues. In all experiments, IOR was observed in the split cue conditions. When central and peripheral cues were presented simultaneously, or when the central cue followed the peripheral cues, no IOR was found. These results suggest that the use of saliency-based processes in endogenous (or exogenous) orienting is a prerequisite for the appearance of IOR.