Date of Award




Document Type


Degree Name

Doctor of Philosophy (PhD)


Department of Psychology


Clinical Psychology

Content Description

1 online resource (viii, 100 pages) : illustrations (some color)

Dissertation/Thesis Chair

Mitchell Earleywine

Committee Members

Sharon Danoff-Burg, Drew Anderson


Assessment, Cannabis, Effort, Motivation, Neuropsychology, Substance abuse, Cognition disorders, Motivation (Psychology)

Subject Categories

Clinical Psychology | Cognitive Psychology


Prior research of the neuropsychological functioning of cannabis users has yielded mixed results, in that some studies identified differences compared to non-users, while others found no group differences at all. A meta-analysis revealed a small effect of cannabis use on the cognitive domains of learning and forgetting, while domains such as attention and processing speed yielded no effect (Grant et al., 2003). However, none of the previous studies assessed the participants' motivation to perform well on the assessment, which may have influenced the results. The present study sought to determine whether motivation is differentially demonstrated in cannabis users compared to non-users, and whether greater motivation can be induced in participants with a motivational statement prior to testing. We also sought to evaluate whether examiner expectancy effects impacted neuropsychological and motivational performance. For two groups of participants, cannabis users and non-users, either a motivational or a neutral statement was administered prior to neuropsychological and motivational testing. The results demonstrated that non-users in the motivational and neutral conditions did not differ in performance, while users in the motivational condition performed significantly better on a test of verbal learning and memory than users in the neutral condition. Additionally, although 68% of users and 67% of non-users were accurately identified by examiners, there were no significant differences in neuropsychological performance between those judged as users and those judged as non-users. The implications and future directions of this research are discussed.