Inhibition of return in visual marking? The importance of the interstimulus interval and the type of search task

Four experiments are presented that examine the possibility that inhibition of return (IOR) may occur in visual marking. Previously, Watson and Humphreys (1997), using a cue duration of 750 ms and an interstimulus interval (ISI) of 250 ms, concluded that IOR was not present in visual marking. In the present study, the first experiment examined three ISIs (250 ms, 500 ms, and 750 ms) with a constant stimulus onset asynchrony (SOA, 1000 ms) in a typical cueing paradigm and failed to find IOR with the short ISI. Based on these findings, the second (feature search) and third (conjunction search) experiments tested for IOR by using a visual marking paradigm with a 500 ms ISI. Evidence for IOR was found in the feature search (preview condition similar to half-elements baseline condition) and not in the conjunction search (preview condition similar to the all-elements baseline). The typical preview effect was found in Experiment 4 with a cue duration 1000 ms and no ISI. Overall, these findings indicate that IOR may play a role in visual marking, but only with feature search tasks and long ISIs between displays.