CUHK electronic theses & dissertations collection

First, although there is some evidence suggesting IOR influences nonspatial attribute-based visual search, the effects observed have been small and inconsistent, have not followed the same time course as more standard IOR, and there is some evidence that the effect may depend on presenting a "neutral attractor" between the cue and target. In Experiments 1(1a,1b) and Experiment 2(2a), participants ii demonstrated a robust color-, and shape-based inhibitory effect that, unlike previous findings, followed a time course similar to that for location-based IOR. Moreover, the effect does not seem to require the presentation of a neural attractor. Experiment 3 and Experiment 2b demonstrated that less or no attribute-based IOR appeared if the cue and target were less salient. The results showed that if the stimuli offer featural differences that are salient enough, the perceptual system uses them to encode the displays, and IOR can be applied to those features.Inhibition of return (IOR) has been reported when a target is preceded by an irrelevant stimulus (cue) at the same location: Target detection is slowed, relative to uncued locations. It is suggested that IOR is a general phenomenon that helps to provide a broad sampling of stimuli in the environment. In recent years, however, the generality of the IOR phenomenon has been questioned. Although there is considerable research demonstrating inhibition of cued locations, and a mountain of evidence for inhibition of cued objects, inhibition of cued nonspatial attributes, like color, shape and orientation, has rarely been explicitly demonstrated. Using a paradigm that has shown robust location-based IOR when relatively richer displays are presented, the present thesis addresses three noticeable gaps in the IOR literature relating to nonspatial feature visual search.Second, the nonspatial-based IOR effect does not seem to be independent of location, as it only occurs when cue and target share not only features, but location. The results suggest that attentional selection can be applied to stimulus properties such as color, shape, and orientation, but that the attentional operations are specified in location-based coordinates. Given location-based IOR appeared in all experiments, repetition of nonspatial features may reflect an additional phenomenon. When the cue and the target do not share location, they can not be the same object, indicating featural IOR is rather object based.Third, in Experiment 4, 5 and 6, when attribute discrimination tasks were required, the attribute-based IOR was gone. So far, there have been a limited number of studies examing the attribute-based discrimination research, and the results of them are mixed. Our results clearly indicated that the attribute-based inhibitory effect does not generalize to higher mental demanding tasks. We suggested that this type of cuing effects can be considered as different manifestations of attentional capture on non-spatial attributes processing, that is, under attribute-based higher demanding tasks observers allocate attestation to locations, rather than to attributes; hence IOR is predominantly location-based.To conclude, these findings shed considerable light on IOR: nonspaital attribute-based IOR can be demonstrated under certain conditions, with rich displays, and with enough stimulus salience. Critically, the effect of inhibition directed to an attribute is tied to the location of the prior stimulus. The effect also depends on the difficulty of the target processing (simple detection task vs. discrimination task).Hu, Kesong.Adviser: Agnes S.Chan.Source: Dissertation Abstracts International, Volume: 72-11, Section: B, page: .Thesis (Ph.D.)--Chinese University of Hong Kong, 2009.Includes bibliographical references (leaves 108-122).Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.Abstract also in Chinese