The contribution of non-ocular response inhibition to visual inhibition of return.
Inhibition of return (IOR) refers to slowed responses to targets presented at the same location as a preceding stimulus. IOR is typically investigated using a cue-target design, in which subjects respond only to the second stimulus of a pair. In such tasks, the measurement of 'true' IOR may be confounded by the effect of non-ocular response inhibition, because the participant must suppress any tendency to respond (e.g. key press) to the first stimulus. This confound may be eliminated using a target-target design, in which responses are made to both stimuli. We assessed the contribution of non-ocular response inhibition to visual IOR, measured in a cue-target task, by testing participants on both cue-target and target-target detection tasks, with identical timings and stimuli. Significant IOR was obtained in both tasks but, at a stimulus onset asynchrony (SOA) of 1400 ms, IOR magnitude was significantly greater in the cue-target condition than in the target-target condition. However, at an SOA of 1800 ms, there was no significant difference in the magnitude of IOR between the two tasks. Thus, a proportion of the total IOR effect observed in visual cue-target tasks can be attributed to non-ocular response inhibition, but this process appears to decay more rapidly than does 'true' IOR, having dissipated by 1800 ms following cue onset.
Coward
R S
RS
Department of Psychology, University of Manchester, Coupland Street, M13 9PL, Manchester, UK.
Poliakoff
E
E
O'Boyle
D J
DJ
Lowe
C
C
D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D011930:Reaction Time / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*