Peripheral stimuli generate different forms of inhibition of return when participants make prosaccades versus antisaccades to them

Inhibition of return (IOR) is usually viewed as an inhibitory aftermath of visual orienting typically seen in the form of slower responses to targets presented in a previously oriented to location. As shown by Taylor and Klein ( 2000 . Journal of Experimental Psychology: Human Perception and Performance, 26 , 1639–1656), the nature of the inhibitory effects resulting from an uninformative cue seem to be contingent on the activation state of the oculomotor system. Here we contrast target discrimination performance following either a prosaccade or antisaccade in the spatial cueing paradigm. Our findings suggest that the level of activation of the reflexive oculomotor system determines the dynamics of the inhibitory effect, wherein an effect nearer to the input end of processing is observed when the reflexive oculomotor system is actively suppressed, and an effect nearer to the output end of processing is observed when the reflexive oculomotor system is actively engaged. These effects interact differently with the Simon effect—providing converging evidence that they are dissociable inhibitory phenomena.