Using the locus-of-slack logic to determine whether inhibition of return in a cue-target paradigm is delaying early or late stages of processing.

Inhibition of return (IOR) is a phenomenon characterized by slower responses to targets at cued locations relative to those at uncued locations. Based on the results of previous research, it has been suggested that IOR affects a process at the input end of the processing continuum when it is generated while the reflexive oculomotor system is suppressed (cf. Satel, Hilchey, Wang, Story, & Klein, 2013). To test this theory, we employed a modified psychological refractory period paradigm designed to elicit input IOR with visual stimuli, allowing us to use the locus-of-slack logic to determine whether an early or late stage of processing was inhibited by IOR. On each trial a visual cue was presented, followed by an auditory target (T1) and visual target (T2) separated by a target-target onset asynchrony (TTOA) of varying lengths (200 ms, 400 ms, or 800 ms). Participants (31 young adults) were instructed to ignore the cue and respond to the targets as quickly and accurately as possible. Eye tracking was used to ensure that participants actively suppressed eye movements during trials. As predicted, the inhibitory effect of the cue was observed at the longest TTOA but not when TTOAs were short, supporting our hypothesis that, when generated while the reflexive oculomotor system is suppressed, IOR affects processing before response selection. (PsycINFO Database Record