Date of Award




Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Psychology


Cognitive Psychology

Content Description

1 online resource (vii, 52 pages) : illustrations (some color)

Dissertation/Thesis Chair

Gordon G Gallup

Committee Members

Ralph Noble


attentional capture, singleton distractor, visual attention, visual interference, Searching behavior, Optical data processing, Visual perception

Subject Categories

Cognitive Psychology


Visual search research investigates whether attentional capture is driven by topdown processes, that is, experimental goals and directives, or by bottom-up processes, that is, the properties of the items within a search display. Some research has demonstrated that participants cannot avoid attending to a task-irrelevant salient item,such as a singleton distractor, even when the identity of the target item is known.Research has also shown that repeating the target feature across successive search displays will prime the visual pop out effect for a unique target (Priming of Pop Out). However, other research has shown that participants can strategically guide their attention and may either locate a target based on its uniqueness (a singleton search mode) or based on knowing and searching for the target feature (a feature search mode). When using the feature search mode experimental participants are attuned to the specific target feature and are less susceptible to singleton distractor interference than when using the singleton search mode. Recent research has compared singleton distractor interference for targets that are variable and uncertain to targets that are constant and certain across search displays. When the target is constant participants can use a feature search mode and should theoretically demonstrate less singleton distractor interference than when targets are variable and they must use a singleton search mode. Indeed, variable targets have historically demonstrated greater singleton distractor interference than constant targets, even when the target feature has been repeated. However, the current experiments found that singleton distractor interference was no greater for variable targets than for constant targets when targets and nontargets did not share shapes across search displays.