Reorienting attention and inhibition of return

In experiments examining inhibition of return (IOR), it is common practice to present a second cue at fixation during the cue-target interval. The purpose of this fixation cue is to reorient attention away from the cued location to ensure that the facilitative effects of spatial attention do not obscure IOR. However, despite their frequent use, relatively little is known about the relationship between fixation cues and IOR. In the present experiments, we examined the role of fixation cues by manipulating their presence in tasks that either did or did not require target identification. When the participants were required to either detect (Experiment 1A) or localize (Experiment 2A) a target, the magnitude of IOR was unaffected by the presence of a fixation cue. In contrast, when the participants were required to identify a target (Experiments 1B, 2B, and 3), IOR was observed only when a fixation cue was presented. This result was obtained regardless of the type of response that was required (two-alternative forced choice or go/no go). The effectiveness of the fixation cue in revealing IOR in these tasks is consistent with its putative role in reorienting attention away from the cued location.