Abstract
Multiple objects exist in our environment. To increase search efficiency, one can achieve this by inhibiting searched locations. Inhibition of return (IOR) may reflect this process. With a cueing paradigm, Posner and Cohen (1984) observed that it takes longer time to revisit a location previously occupied by a non-informative cue. This effect is termed IOR. It was proposed that disengagement from the cued location is critical to the manifestation of IOR. However, the importance of disengagement remains a doubt. For example, IOR can be observed in the absence of the fixation stimulus that attracts attention from the previously cued location. In the current study, we proposed that both endogenous and exogenous attentional disengagement from the cued location can produce IOR. Endogenous disengagement was manipulated by the use of different cue validities: 20% (Experiment 1), 50% (Experiment 2), or 80% (Experiment 3). Exogenous disengagement was manipulated across these three experiments by giving post-cue fixation stimulus or not. The results supported our predictions. IOR occurred when there was endogenous disengagement and/or exogenous disengagement. IOR was not observed when there was neither endogenous nor exogenous disengagement (no post-cue fixation stimulus, 80% cue validity). The importance of disengagement to IOR was demonstrated.