Inhibition of return lasts longer at repeatedly stimulated locations than at novel locations

Inhibition of return (IOR) refers to the fact that it takes longer for people to attend to recently examined locations than to novel locations. It has been argued that a single mechanism governs both IOR and negative priming (NP). If this is true, IOR and NP should share similar characteristics. Since NP depends on the use of repeated stimuli, in this study the dependence of IOR on repeated stimuli was explored. Experiments 1A—1D showed that, at longer cue-to-target-onset asynchrony (CTOA) intervals (613 and 906 msec), IOR could be observed only at repeatedly stimulated locations. However, IOR was observed when CTOA was short (253 msec) regardless of stimulus repetition. Experiments 2 and 3 replicated Experiments 1A—1D with a within-subjects design. The important role of memory representations in IOR is proposed.