Two Forms of Inhibition of Return Dissociated by Reflexive Oculomotor Engagement

Abstract

Inhibition of return (IOR) is usually viewed as an inhibitory aftermath of visual orienting typically seen in the form of slower responses to previously cued targets. Arguments have been posed for ‘attentional’ and ‘motoric’ components to this effect, as well as ‘space’ and ‘object’ distinctions. Taylor and Klein (2000) suggested that there may be two dissociable forms of IOR - one with its effect closer to the input end of the information processing continuum, and one effect closer to the output end of this continuum. This thesis will explore various boundary conditions on this dissociation in order to reconcile discrepancies between the ‘two forms’ account of inhibitory cueing and other theoretical frameworks for these phenomena. We conclude that there are two forms of inhibition of return: an input form that operates as a bias against previously attended objects, and an output form that operates as a spatial bias against orienting.