The effects of memory load on the time course of inhibition of return.

Inhibition of return (IOR) refers to a processing disadvantage at a recently attended location. It is generally agreed that when elicited in a cue-target task, IOR will not be apparent until attention is disengaged from the originally cued location and returned to a neutral state. Here we test the hypothesis that when such disengagement is dependent on endogenous control, a secondary task that taxes working memory capacity should delay the appearance of IOR. Participants were given a six-item verbal working memory load prior to the peripheral cue in a cue-target detection task. Consistent with the hypothesis, the appearance of IOR was delayed on trials for which participants had to hold information in working memory. Converging evidence was derived from a second experiment in which the time course of IOR's appearance, when we added a central cue to exogenously remove attention from the peripheral cue, was unaffected by the memory load.