Decades of visual attention research have predominantly used pictorial search paradigms that cue participants with the exact perceptual details of the target. However, in everyday life, people often search for categories rather than specific items (i.e., any pen rather than a specific pen). To study visual attention in a more realistic context, researchers can use categorical search paradigms that cue participants with text indicating the target category. In these instances, one must rely on long-term memory to retrieve categorical features of the target. Both experiments in this study were a reanalysis of experiments previously designed and collected by Schmidt and colleagues at Stony Brook University. In Experiment One, participants completed a pictorial or categorical search. Eye movements were used to assess search performance and electrophysiological data were assessed in response to the target cue and RI before search to evaluate the encoding and maintenance of the target. Although participants in the categorical condition were slower and exhibited weaker guidance, as measured by initial saccade direction (to the target, strong; to a distractor, weak), no differences in power or synchronous activity were observed when compared across target cue types. However, when the data were separated by guidance (strong or weak), categorical cues produced significantly more frontal-posterior theta synchrony before good guidance trials compared to bad guidance trials. In Experiment Two, participants were given categorical and specific text cues (i.e., the text always corresponded to a single target item). Specific text cues were expected to behave similarly to pictorial cues because participants knew the exact target features. Whereas specific text cues resulted in superior search performance across several measures, minimal neural differences were observed. The results from Experiment One implicate frontal-posterior theta synchrony as a potential neural marker of categorical information used to direct attention during visual.
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Doctor of Philosophy (Ph.D.)
College of Sciences
Psychology; Human Factors Cognitive Psychology
Length of Campus-only Access
Doctoral Dissertation (Open Access)
Phelps, Ashley, "Neural Dynamics of Categorical Representations Used for Visual Search" (2023). Electronic Theses and Dissertations, 2020-. 1635.