Dissertations, Theses, and Capstone Projects

Date of Degree

9-2023

Document Type

Dissertation

Degree Name

Ph.D.

Program

Psychology

Advisor

Anjali Krishnan

Committee Members

Elizabeth Chua

William Esber

Natalie Kacinik

Matthew Crump

Subject Categories

Behavior and Behavior Mechanisms | Cognitive Neuroscience | Cognitive Psychology | Cognitive Science | Experimental Analysis of Behavior | Neurosciences | Psychological Phenomena and Processes | Systems Biology

Keywords

Autism Spectrum Disorder, Typicality Gradient, Categorization, Category-based inference, fMRI

Abstract

Individuals diagnosed with Autism Spectrum Disorder (ASD) often encounter challenges in assimilating atypical exemplars into their categorical prototypes, a cognitive hurdle that can impact their interpretative and integrative capacities. Addressing this problem, the present research sought to develop a robust methodological approach to reduce the effect of this disparity. We examined the elements embedded within the category's internal structure, with the intention of experimentally attenuating the pronounced typicality effect, which is often exaggerated in ASD.

Across four experiments, the thesis investigated the cognitive and neural underpinnings that shape the access to the typicality gradient intrinsic to a category's structure. The first three experiments centered on deciphering the influence of hierarchical inclusion, to understand interrelation with typicality effects and categorization knowledge. Findings from Experiment 3 revealed that hierarchical inclusions, though essential, were insufficient in isolation to mitigate the typicality effect in ASD individuals.

Experiment 4 combined hierarchical information with specific exemplar properties. This integrated approach demonstrated the potential to diminish the typicality effect. Behaviorally, across neurotypical individuals (labeled as healthy controls in figures to match previous literature), those manifesting Autistic Traits, and those self-attesting as ASD, showed attenuated typicality effect when category membership and exemplar property association were explicitly primed, especially for atypical exemplars. Complementing the behavioral data, fMRI investigations mapped the neural network activated during the differential processing of atypical exemplars, revealing regions that have been previously implicated in language, deductive reasoning, and critical thinking such as the supramarginal gyrus, frontal pole, and middle frontal gyrus.

In summary, this research presents a novel approach to addressing a cognitive challenge in ASD with respect to the categorization of atypical exemplars. By assimilating this methodology into pedagogical strategies tailored for ASD, there is a promising potential to expand categorical boundaries, thus fostering a more inclusive cognitive environment for neurodivergent individuals.

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