The role of cue processing in advancing the onset of inhibition of return.

The appearance of inhibition of return (IOR), a phenomenon where invalid trials produce faster reaction times than valid trials, is delayed in target discrimination tasks at SOA of 700 ms compared to target localization tasks where it appears at SOA of 300 ms (Posner & Cohen, 1984; Lupiáñez, Milan, Tornay, Madrid, & Tudela, 1997). Our goal was to see whether deeper processing of the cue can accelerate the onset of IOR in target discrimination tasks (Gabay, Charras, Funes, Chica, & Henik, 2012), predicting that the cue processing will accelerate IOR's appearance at SOA of 100 ms. In our study, two white hollow squares (2.5o each side) were presented to the right and left of the fixation cross (retinal eccentricity of 6.84°). One of the two squares changed color (to red or green) which served as the non-predictive cue. Following SOAs of 100, 300, 600, or 1000 ms, the target (blue or yellow circle) appeared inside one of the two hollow squares. Participants performed identical target discrimination task with additional task about the cue: one which did not require any processing of the cue, a second which required identifying the cue's color, and the third which required identifying the cue's location. The results showed IOR at the SOA of 100 ms in the cue color discrimination condition, however, IOR was not observed at any of the SOAs in the cue localization condition. IOR was also observed at the SOAs of 100 and 600 ms in the no cue task condition. Although the findings show IOR at the SOA of 100 ms for the cue color discrimination condition as hypothesized, the no cue processing condition produced IOR at earlier SOAs than what is normally observed, possibly indicating that factors other than processing of the cue affect the onset of IOR. Meeting abstract presented at VSS 2015.