Using temporal order judgments and colour perception to dissociate inhibitory cueing effects

Inhibition of return (IOR) is an inhibitory aftereffect of visuospatial orienting, typically observed in the spatial cueing paradigm by way of slower responses to cued rather than uncued targets. Recent work suggests that there are two forms of IOR (Chica, Taylor, Lupianez & Klein, 2010; Hilchey, Klein & Satel, 2014; Klein & Redden, 2018; Redden, MacInnes & Klein, 2021); one operating nearer the input end of the information processing continuum affecting the quality of inputs and the other nearer the output end affecting responding. The type of effect that is manifest is contingent upon the activation state of the reflexive oculomotor system at the time the effect is generated. However, early work assessing the perceptual effects of IOR using temporal order judgments (TOJ; Posner, Rafal, Choate & Vaughan, 1985; Maylor, 1985; Klein, Schmidt & Muller, 1998) showed no effect on arrival time judgments, suggesting IOR was, in these studies, acting at a post-perceptual information processing stage. We examined this theoretical and empirical inconsistency in a TOJ task, wherein participants were required to make either a prosaccade (output form) or antisaccade (input form) in response the onset a spatially uninformative peripheral cue, and subsequently execute a TOJ or speeded colour identification response. We found inhibited perceptual processing for the first time affecting TOJs when the input form was generated, but no inhibitory effect on perception when the output form was generated. These findings support the theory that there are two forms of IOR: an input effect influencing perception, and an output effect influencing responding.