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Clinical Psychology, PhD
People tend to prefer smaller-but-sooner over later-but-larger rewards, indicating the subjective value of a reward is discounted as a function of time. This phenomenon is referred to as delay discounting and represents a facet of impulsivity that is associated with reward processing. Despite the empirical literature surrounding delay discounting, the underlying mechanisms are not yet well established. The current study investigated whether delay discounting belongs more to one grouping – personality traits or cognitive functioning – than the other. Additionally, neuroimaging metrics (i.e., cortical thickness) was also examined, as it has the potential to mediate these pathways to delay discounting. Data from the Human Connectome Project was used for the current study and included behavioral and neuroimaging data on 1,051 healthy young adults. Exploratory and confirmatory factor analysis (EFA and CFA, respectively) were used to investigate proposed relationships between personality and cognitive variables and delay discounting and examine the extent that neuroimaging variables mediate the relationship. Results from the exploratory factor analysis revealed support for two separate latent constructs of cognition and personality. A progression of CFA models in structural equation modeling demonstrated evidence for the relationship between cognition and delay discounting, while personality appeared to have little explanatory power in understanding delay discounting. Results from the analysis examining cortical thickness in a selected brain region of interest did not provide evidence for a mediative relationship between cognition and delay discounting. This study helps to clarify and explain the construct of delay discounting and highlights the importance of cognition in reward-based decision-making.
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Levy, Sarah, "A Factor Analytic Examination of the Underlying Mechanisms of Delay Discounting" (2020). Psychology Department Dissertations. 9.