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 they detect a target stimulus following the presentation of a cue that indicates the location in which the target will appear. The cue can be exogenous (or peripheral), or endogenous. Inhibition of return results from oculomotor activation, regardless of whether it was produced by exogenous signals or endogenously. Although IOR occurs for both visual and auditory stimuli, IOR is greater for visual stimuli, and is studied more often than auditory stimuli. 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 they detect a target stimulus following the presentation of a cue that indicates the location in which the target will appear. The cue can be exogenous (or peripheral), or endogenous. Inhibition of return results from oculomotor activation, regardless of whether it was produced by exogenous signals or endogenously. Although IOR occurs for both visual and auditory stimuli, IOR is greater for visual stimuli, and is studied more often than auditory stimuli. IOR was first described in depth by Michael Posner and Yoav Cohen, who discovered that, contrary to their expectations, reaction times (RT) to detect objects appearing in previously cued locations were initially faster to validly cued location (known as the validity effect), but then after a period of around 300 ms, response times to a previously cued location were longer than to uncued locations. Specifically, IOR was described as 'an inhibitory effect produced by a peripheral (or exogenous) cue or target.'