Search

In the process of searching for targets, our visual system not only prioritizes target-relevant features, but can also suppress nontarget-related features. Although this template for rejection has been well demonstrated, whether the features (i.e. the objects) or locations are suppressed remains unresolved due to the experimental paradigms in previous studies: in particular, object-based templates for rejection were confounded with location-based inhibition in visual search paradigms. The present study examined an object-based template for rejection by introducing search arrays comprised of two overlapping shapes with search items distributed along the shape's contours. To discourage location-based inhibition, the two shapes were spatially intermingled (Experiment 1), rotated (Experiment 2), or jiggled (Experiment 3). Participants identified the colour of a target cross. The pre-cue indicated the shape in which the target would appear (positive cue condition), the shape in which only distractors would appear (negative cue condition), or the shape that was irrelevant to the current search array (neutral cue condition). In all three experiments, the reaction times for the negative cue condition were shorter than those for the neutral cue condition, which is a hallmark of the object-based template for rejection effect, even under conditions in which location-based inhibition was discouraged. [ABSTRACT FROM AUTHOR]

The human visual system can actively prioritize task-relevant features to search for a target. Recent studies have reported cases in which the system may suppress irrelevant features by using a template for rejection. However, in those studies, the templates used for rejection were limited to the color domain, and they have yielded mixed results. Our literature review identified three differences among studies that may be responsible for such mixed results: differences in the spatial segmentation of items (i.e., segregated or intermixed across the display), differences in how features are defined and reported (i.e., combined or separate), and differences in cue lead times (short or long). Participants searched for a target-line segment in a shape and identified its orientation from among non-target line-shaped compound shapes that were preceded by one of three cue displays. Positive cues indicated that the target segment would appear in a shape, and negative cues that it would not appear in a shape. Neutral cues indicated that a particular shape would not appear in the current search display. The results demonstrated that reaction times were faster under the negative-cue condition than the neutral-cue condition, reflecting the effect of a shape-based template for rejection (Experiment 1). Experiment 2 replicated the absence of the effect in the shape domain. Experiment 3 indicated that the template-for-rejection effect occurred only when the cue lead time was relatively long, suggesting that time is required (approximately 2,400 ms or longer) for the visual system to form rejection templates. Experiment 4 excluded the possibility that a confound in the target-defining/reporting feature was involved. These results indicated that apparent inconsistencies in research on the template-for-rejection effect can be explained in terms of the time required for templates to be configured. [ABSTRACT FROM AUTHOR]