Inhibition of Return

Inhibition of return (IOR) refers to an orientation mechanism that briefly enhances (for approximately 100-300 milliseconds (ms)) the speed and accuracy with which an object is detected after the object is attended, but then impairs detection speed and accuracy (for approximately 500-3000 milliseconds). IOR is usually measured with a cue-response paradigm, in which a person presses a button when he or she detects a target stimulus following the presentation of a cue that indicates the location in which the target will appear. Oftentimes, the cue is exogenous (or peripheral), as opposed to endogenous because endogenous cues do not tend to activate IOR. Although IOR occurs for both visual and auditory stimuli, IOR is greater for visual stimuli, and is studied more often than auditory stimuli.