Learning to categorize visual stimuli is a fundamental cognitive skill underlying both everyday functioning and professional competencies in domains such as radiology and airport security screening. Categories may be very simple or highly complex, with accurate categorization dependent on multiple interacting features. General recognition theory (GRT) models uniquely allow examination of feature dimension interactions, but basic questions remain about the applicability of such models and the 2x2 categorization tasks (four-alternative forced choice) employed in studies which use them. Findings in several studies that factorially combine 2 levels of 2 stimulus dimensions indicate a common pattern of perceptual advantage for the category that is high on both dimensions, despite examining stimuli as diverse as simulated human faces, baggage x-rays, and mammograms. Because of the ambiguous ground truth of these applied studies, their conclusions are limited by the inability to rule out the influence of task artifacts on their results. The present work fills this gap in the literature and seeks to disambiguate such findings by examining the contributions of task artifacts such as response mapping and assessing the sensitivity of the modeling paradigm using simple stimuli. Participants learned categories of simple two-dimensional stimuli produced by various manipulations of a basic category construction, and GRT-wIND models were fit to their responses. Results indicate that the model is sensitive to manipulations of the perceptual space and category structures. Further, the previously observed pattern advantaging one of four categories is observed here despite the absence of such a relationship between the feature dimensions in the objective category constructions. The effect is largely mitigated, however, by altering the response locations such that they are no longer orthogonally mapped to their corresponding categories. These findings further evidence the utility and sensitivity of the GRT-wIND model and suggest updates to best practices in applying the four-alternative forced choice task.
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Doctor of Philosophy (Ph.D.)
College of Sciences
Psychology; Human Factors Cognitive Psychology
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Killingsworth, Clay, "Modeling the Relationship between Perceptual and Stimulus Space in Category Learning" (2021). Electronic Theses and Dissertations, 2020-. 958.