The ERP Study On Object-based Inhibition Of Return

Inhibition of Return (inhibition of return, IOR) is a suppression mechanismfound within the field of exogenous spatial selective attention that helps to improvethe efficiency of human attention to search. Since Posner and Cohen found this effectfor the first time in1984, IOR has became the focus of attention study in the field ofcognitive psychology and cognitive neuroscience. As the number of researches ofspatial-based inhibition of return was growing, Object-based inhibition of return wasfirst discovered by Tipper et al in1991. This effect is a phenomenon that attention toreturn to the object previously cued is restrained, and this inhibition will follow theobject to a new location. The researchers developed different experimentalparadigms. Both the static paradigm and the dynamic paradigm are used to explorethe mechanism of Object-based IOR.There are considerable differences between the researchers aboat the essence ofobject-based inhibition of return. Some behavior evidences support the hypothesis ofinhibiting object representation, whereas some others support the hypothesis of spacedynamic updating. As the limitation of the experimental paradigms, the behaviorresults obtained in static and dynamic paradigms are difficult to integrate. What’smore, the studies of object-based inhibition of return are short of direct evidence ofERPs, and fMRI findings show that the mechanism of object-based IOR iscontroversial in the neural level. Therefore this study designs two experiments, inorder to further prove the separation of object-based and space-based inhibition ofreturn, as well as to revesl the cognitive neural mechanisms of the object-based IOR.In experiment1which is a behavioral research, we used the typical cue-targetparadigm. We regulate the relationship of cue and target (the same position in thesame object, different position in the same object, corresponding to the position indifferent objects), and change the time interval between cue and target onset (StimulusOnset Asynchrony, SOA), to investigate how time course influence the space-basedand the object-based inhibition of return. As a result, main effects of both the cuedlocations and SOA are significant. when SOA is500ms, both object and spaceinhibition of return achieve the largest amount of suppression. As the rising of SOA,the inhibition effect reduced. This restlts provide a evidence for separation of thespace-based and the object-based inhibition of return.Based on the results of experiment1, in Experiment2that SOA is selected 500ms We investigated object IOR and space IOR evoked ERP component amplitudedifferences by event-related potentials. The results of Experiment1was repeated onthe behavioral level. The the ERPs results showed that cued location (target and cueappear in the same location in the same object) evoked greater N1and P3amplitude.What’s more, the difference waves that reflected object-based and space-based IORware significantly different.The results of the two experiments indicate that in the static paradigm object-based inhibition of return are found both in behavior level and in EEG levels. And thishas verified the separation of object-based inhibition of return and space-basedinhibition of return. The results support the hypothesis of inhibition of objectrepresentations.