Joseph Houpt (Committee Member), Alan Pinkus (Committee Member), Valerie Shalin (Committee Member), Scott Watamaniuk (Advisor)
Doctor of Philosophy (PhD)
The current study simultaneously examined the potentiality of a magnocellular attentional advantage and the competition between top-down and bottom-up processing on attention during visual search as measured by covert and overt visual attention. Specifically, the study tested two opposing views of the competition between top-down and bottom-up processing. The contingent involuntary orienting hypothesis (Folk, Remington, & Johnston, 1992), states that goal directed search is not affected by target-irrelevant stimuli. In contrast, the distractor interference paradigm (Theeuwes, 1994), states that goal directed search can be affected by target-irrelevant stimuli if more salient than the rest of the search array. The study utilized a search array of contrast-equated orientation and spatial frequency modulated Gabor patches to preferentially activate the magnocellular and parvocellular visual streams in order to test for a magnocellular attentional advantage. Participants were asked to find a singleton target Gabor patch amongst a field of distractor Gabor patches. The results were mixed. Top-down search for a spatial frequency singleton provided support for the distractor interference paradigm while top-down search for an orientation singleton provided support for the contingent involuntary orientating hypothesis. These mixed results suggest top-down versus bottom-up search is more complicated than these two theories suggest. By demonstrating the effect of a target-irrelevant distractor on response time and accuracy, I provide that a bottom-up attentional priority exists when performing a top-down search for an orientation singleton, but not for a spatial frequency singleton. Additionally, the current study could find no evidence for a magnocellular attentional advantage.
Department or Program
Department of Psychology
Year Degree Awarded
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