Date of Award

5-6-2009

Document Type

Dissertation

Degree Name

Doctor of Psychology (PsyD)

Department

Psychology

First Advisor

Donald U. Robertson, Ph.D.

Second Advisor

David J. LaPorte, Ph.D.

Third Advisor

Dr. Derek R. Hatfield

Fourth Advisor

Derek R. Hatfield, Ph.D.

Abstract

This study investigated the concepts of sense of time, inhibition and working memory in college-aged students. Barkley’s Theory of Attention-Deficit/Hyperactivity Disorder (ADHD) (1997a) identifies hierarchical relationships between inhibition, working memory and sense of time. However, other research has hypothesized that sense of time is not related to working memory, but is instead related to deficits in an internal, cognitive clock. Based on these competing theories, this experiment tested the hypothesis that sense of time is related to inhibition above and beyond working memory. Fifty college-age participants completed tasks measuring inhibition, verbal working memory, visuospatial working memory and sense of time. Two facets of sense of time were measured. Participants completed a time reproduction task; however, because time reproduction tasks confound sense of time with a motor response, participants also completed a time discrimination task. Finally, self-report measures were used to assess for symptoms of ADHD, trait anxiety and the Behavioral Inhibition System. Inhibition was not related to time reproduction or time discrimination. In addition, time reproduction was not related to working memory, ADHD or trait anxiety. However, time discrimination was related to working memory, self-report symptoms of ADHD and trait anxiety. Subsequent analyses showed that visuospatial working memory predicted above and beyond verbal working memory. When tested in a stepwise fashion, self-report measures of ADHD and trait anxiety both predicted significant variance in time discrimination ability above and beyond working memory. Further analyses showed that, although participants were able to solve medium level time discrimination items using working memory, as the level of difficulty increased and exceeded the capacity of working memory, participants were forced to rely more on their sense of time. The results of this study provide evidence that symptoms of ADHD and anxiety are related to “purer” deficits in sense of time as related to an internal clock.

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