Dysfunctional decision-making is characteristic of numerous psychiatric disorders including schizophrenia, mood disorders, ADHD, eating disorders, pathological gambling and substance abuse. The rodent Gambling Task (rGT) is analogous to the Iowa Gambling Task (IGT) and models risky decision-making in rodents. The rGT has unique response options that range from high probability of small rewards and lower probability of penalty to responses that result in low probability of larger reward and higher probability of penalty. Similar to the IGT, the optimal rGT strategy is exclusive choice of an intermediate reward/penalty response option. Importantly, similar baseline behavior exists between human and rodent subjects and supports the validity of the rGT in examining different behavioral phenotypes. In addition to strong face and construct validity, the rGT measures motor impulsivity and decision-making behaviors and integration- or dissociation- of these two behaviors is essential to characterizing the impact of different neurobiological or pharmacological manipulations. Due to monoamines' (dopamine, serotonin and norepinephrine) integral role in the modulation of reward assessment and impulsivity, we examined the impact of several monoaminergic-altering drugs: d-amphetamine, eticlopride, cocaine, methylphenidate (Ritalin), and bupropion (Wellbutrin). Although each drug differed in mechanism of action and affinity for specific monoamine transporters, only slight behavioral differences were observed in the rGT. Interestingly, all monoamine-enhancing drugs increased selection of the lowest risk option and significantly shifted behavior away from the optimal response. / A Thesis submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester, 2012. / March 26, 2012. / Decision Making, Monoamines, rGT / Includes bibliographical references. / Joshua S. Rodefer, Professor Directing Dissertation; Frank Johnson, Committee Member; Walter R. Boot, Committee Member.

Working memory (WM) and inhibitory control (IC) are considered related but separable executive functions (EFs) among adults and adolescents. Although available evidence seems to suggest that these two constructs have not yet diverged among preschool children, aspects of previous studies of preschool populations leave open questions regarding findings indicating a unitary factor structure. To address limitations of previous studies, this study used well-defined tasks to examine the extent to which EF in preschool children was best represented by a single factor or by separate but correlated WM and IC factors. Confirmatory factor analysis was used to test for the presence of a 2-factor structure of EF among preschool children. Additionally, two types of inhibitory tasks, conflict and suppression, were examined in an attempt to extend evidence that suppression tasks differ more from working memory tasks than do response conflict tasks. Based on evidence that WM and IC measured during preschool relate differently to a variety of academic and behavioral outcomes, it was hypothesized that a model including separate latent factors for each executive function would fit the observed data better than a single-factor model. The model that included separate but related factors for WM and IC provided a significantly better fit to the data than a single-factor model, indicating the presence of separate WM and IC factors in this sample. / A Thesis submitted to the Department of Psychology in partial fulfillment of the reqiurements for the degree of Master of Science. / Fall Semester, 2012. / September 12, 2012. / executive function, inhibitory control, preschool children, working memory / Includes bibliographical references. / Christopher Lonigan, Professor Directing Thesis; Janet Kistner, Committee Member; Michael Kaschak, Committee Member; Carol Connor Additional, Committee Member.

Reading is a critical skill that is influenced by socioeconomic factors. It is well-established that reading is influenced by genetic and environmental factors, and recent studies have suggested that genetic effects on reading may be moderated by socioeconomic factors. However, findings of such gene-environment interactions are inconsistent for reading and cognitive ability, and no known study has investigated moderating effects across the full range of reading ability in elementary-aged readers when foundational reading skills are established. The current study filled this gap in the literature by testing for moderating effects of six socioeconomic status (SES) variables on genetic and environmental influences on reading in a diverse sample of 1,709 twin pairs in third-fifth grades. Structural equation moderation models that allowed for a moderating effect of SES on the mean of reading as well as genetic and environmental variance components were fit separately for six SES variables. No significant genetic moderation was found, however, there was a pattern of moderation on shared environmental variance for four of the six SES variables. Overall, there was a trend of slightly more variance in reading in children of lower SES families and this increased variance was due to more variability in their shared environmental experiences. / A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2012. / August 7, 2012. / gene-environment interaction, reading, socioeconomic status, twin study / Includes bibliographical references. / Christopher Schatschneider, Professor Directing Dissertation; Barbara Foorman, University Representative; Jeanette Taylor, Committee Member; Richard K. Wagner, Committee Member; Carol McDonald Connor, Committee Member.

The purpose of this study was to investigate the multi-faceted nature of morphological knowledge, the relationship between morphological and vocabulary knowledge, and the relationship of these skills to reading comprehension in adults enrolled in GED-level Adult Basic Education (ABE) courses. Morphological awareness, an understanding of how words can be broken down into smaller units of meaning, has emerged as an important contributor to children and adults' reading comprehension. However, there has been a lack of research investigating the construct of morphological knowledge and its relationship with vocabulary knowledge in adults with low literacy. A series of confirmatory factor analyses (CFAs) revealed that morphological knowledge was multidimensional as evidenced by a breakdown of tasks with only real words versus tasks with only non words. Additionally, morphological knowledge, both real word and non-word, were separate, distinct factors from vocabulary knowledge. Finally, real word morphology, non-word morphology, and vocabulary knowledge accounted for a large amount of variance in reading comprehension for ABE students. The results of this study have important implications for morphological and vocabulary instruction in ABE programs. Moreover, the results of this study have practical implications for researchers assessing the construct of morphology because the findings indicate that different measures of morphological knowledge may be tapping disparate facets of the construct. / A Thesis submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / October 17, 2012. / Adult Basic Education, Morphological awareness, Reading comprehension, Vocabulary / Includes bibliographical references. / Christopher Schatschneider, Professor Directing Thesis; Carol Connor, Committee Member; Sara Hart, Committee Member; Richard Wagner, Committee Member.

The present study utilized a sample of 316 first grade students followed through fourth grade to evaluate the dynamic relations between vocabulary and reading comprehension as measured by two expressive vocabulary measures and two passage comprehension measures to determine the leading and /or lagging relations between the two variables. Using latent change score (LCS) modeling, three sets of models were fit to the repeated measurements of vocabulary knowledge and reading comprehension. In the first set of models, four competing univariate models were fit separately to the two constructs. For vocabulary, the model in which the changes-to-changes parameters were estimated was determined to be the best fitting model (Voc; χ2 (35) 50.30, p < .045; RMSEA = 0.037), and the dual change model was determined to be the best fitting model for reading comprehension (χ2 (36) = 254.56, p < .045; RMSEA = 0.037). In the second set of models, four competing bivariate models were fit jointly to the two constructs. It was determined the model with the coupling parameter (relating previous level of one variable to future changes in the other variable) estimated vocabulary to changes in reading comprehension, was the best fitting model (χ2= 362.35 df = 25, p < .001, RMSEA = 0.077). Lastly, four extensions of the bivariate DCS model were fitted to the data, and the model in which only the vocabulary changes to reading comprehension changes parameter was estimated was the best fitting model (χ2= 350.80, df = 123, p < .001, RMSEA = 0.077). These results describe a dynamic system in which yearly changes in comprehension were significantly determined by prior level of comprehension (β = -0.573) and by prior yearly changes in vocabulary (ξ = 0.434). Furthermore, there is a dynamic system such that yearly changes in vocabulary knowledge were significantly determined by previous level of vocabulary knowledge (β = -0.327). These findings suggest vocabulary instruction to be vital for future reading comprehension abilities, but further investigation of this longitudinal relationship is warranted to determine if reciprocal relations exist outside of this sample. / A Thesis submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / November 5, 2012. / latent change score modeling, longitudinal, methodology, reading comprehension, vocabulary knowledge / Includes bibliographical references. / Richard Wagner, Professor Directing Thesis; Chris Schatschneider, Committee Member; Jon Maner, Committee Member.

Comprehension is a foundational skill that is essential to learning. One often overlooked aspect of teaching and assessing comprehension is the role of the properties of the text itself. The current study investigated various indices of text features that have been found to impact the comprehensibility of texts in controlled, experimental studies. Factor analytic techniques were used to investigate the covariation among these indices on a set of 745 texts obtained from academic settings. The results of the text analysis were then applied to a sample of over 1 million students from grades 3 through 10, where both text features and overall reading comprehension ability were ascertained to investigate the relationship between factors of text cohesion and reading comprehension. Results revealed three factors of text cohesion; surface code, textbase, and situation model that consisted of measures of syntactic simplicity, word frequency, referential cohesion, semantic relatedness, and causal cohesion. Results from a two-level hierarchical model showed that factors of cohesion accounted for a significant amount of variance in comprehension above that accounted for by traditional readability measures. / A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2012. / July 19, 2012. / Coh-Metrix, Comprehension, Construction Intergration Model, Text cohesion / Includes bibliographical references. / Christopher Schatschneider, Professor Directing Dissertation; Barbara Foorman, University Representative; Richard K. Wagner, Committee Member; Jon Maner, Committee Member; Jeanne Wanzek, Committee Member.

The purpose of this study was to examine the psychometric properties of a newly designed measure of self-regulation for third grade students, The Remembering Rules and Regulation Picture Task (RRRP). Though research has shown that self-regulation is important for school success, there has been little advancement in how self-regulation is measured. An item analysis (IRT) revealed that a multidimensional model provides the best description of the data and that the RRRP is comprised of two separate factors. The second aim of this study was to determine if the RRRP predicted growth in reading and math skills. Results using hierarchical linear modeling (HLM) revealed that the RRRP was found to be significantly associated with gains in math and reading. For math, performance on the RRRP significantly predicted performance on the applied problems test in the spring. For reading, the RRRP was associated with students' scores on the picture vocabulary measure. The RRRP appears to be a promising measure of children's self-regulation skills. / A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2012. / August 8, 2012. / academic achievement, children, executive function, math, reading, self-regulation / Includes bibliographical references. / Carol Connor, Professor Directing Dissertation; Christopher Schatschneider, Professor Co-Directing Dissertation; Barbara Foorman, University Representative; Richard Wagner, Committee Member; Walter Boot, Committee Member.

This study utilized confirmatory factor analyses and latent change score analyses to model individual and developmental differences in a longitudinal study of children's writing. Participants were 158 children who completed a writing sample each year from 1st through 4th grade. At all four time points, a four-factor model of writing provided the best fit to the data. The factors were macro-organization (presence of topic sentence, number of key elements, and order of ideas), productivity (number of words and number of unique words), complexity (average number or words per sentence and number of connectives), and vocabulary (average number of syllables and average number of characters per word, and percentage of multisyllabic words). The latent change score analyses demonstrated significant relations among the intercepts of macro-organization, productivity, and complexity factors, indicating that children with higher initial levels of one skill were also likely to have higher initial levels of the other. Productivity was also identified as a leading indicator of complexity, such that higher levels of productivity predicted subsequent increases in complexity over time. / A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2012. / October 29, 2012. / elementary children, writing development, writing scoring, written language / Includes bibliographical references. / Richard K. Wagner, Professor Directing Dissertation; Barbara Foorman, University Representative; Christopher Schatschneider, Committee Member; Jon Maner, Committee Member; Young-Suk Kim, Committee Member.

Studies on the efficacy of mental health courts (MHCs), criminal courts designed to decrease the number of mentally ill offenders in the criminal justice system and limit time spent incarcerated, find a reduction in recidivism rates for participants. Unfortunately, methodological limitations diminish the conclusions drawn from these studies. Additionally, untested assumptions are made about the necessary components of an MHC (e.g., voluntariness, type of judge-defendant interaction) and the types of offenders (e.g., felons) allowed. This study examined if a novel MHC impacted recidivism in a sample of mentally ill offenders, when compared both to mentally ill offenders placed into traditional criminal court and to themselves pre-enrollment. All offenders were followed for 12 months, and data for the MHC group were also obtained for the 12 months prior to index offense. Overall, results were consistent with previous reports on the effectiveness of MHCs. The MHC sample had a lower overall rate of recidivism and a longer time to new charge than the control group, even when controlling for relevant covariates. Groups did not significantly differ on re-arrest severity. These findings largely held when examining subgroups of felony, misdemeanor, violent, and non-violent offenders. Within-subjects analyses of the MHC group suggest pre-post improvements on occurrence of re-arrest and months to re-arrest, but a tendency to increase the severity of rearrest. Within the MHC group, recidivism outcomes did not significantly differ between misdemeanor and felony offenders and between violent and non-violent offenders. Implications regarding mechanisms of change in MHCs are discussed. / A Dissertation submitted to the Department of Psychology in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2012. / July 18, 2012. / diversion, mental health court, mentally ill offender, recidivism / Includes bibliographical references. / Joyce Carbonell, Professor Directing Dissertation; William Bales, University Representative; Edward Bernat, Committee Member; Mark Licht, Committee Member; Chris Schatschneider, Committee Member.

Central glucagon-like peptide 1 receptor (GLP-1R) stimulation suppresses food intake, and hindbrain GLP-1 neurons project to numerous feeding-relevant brain regions. One such region is the nucleus accumbens (NAc), which plays a role in reward and motivated behavior. Using immunohistochemical and retrograde tracing techniques in rats, we identified a robust projection from GLP-1 neurons in the nucleus of the solitary tract to the NAc.We hypothesized that activation of NAc GLP-1Rs suppresses feeding.When injected into the NAc core of rats at doses subthreshold for effect when administered to the lateral ventricle, GLP-1 significantly reduced food intake relative to vehicle at 1, 2, and 24 h posttreatment. The same doses had no effect\ when injected into the NAc shell. NAc core treatment with ventricle-subthreshold doses of the GLP-1R antagonist exendin (9 -39) caused significant hyperphagia at 2 h posttreatment, suggesting that endogenous stimulation of NAc core GLP-1Rs plays a role in limiting food intake. It has been suggested that GLP-1 can cause nausea, but we found that NAc core administration of GLP-1 did not cause a conditioned taste aversion to saccharin, suggesting that the anorexic effect of NAc core GLP-1 is not caused by malaise. Finally, we observed that NAc core injection of GLP-1 significantly increased c-Fos expression in the NAc core. We conclude that that GLP-1Rs in the NAc play a physiologic role in food intake control, and suggest that the GLP-1 projection to NAc core may link satiation signal processing in the hindbrain with forebrain processing of food reward. / A Thesis submitted to the College of Arts and Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / August 30, 2012. / central nervous system, food intake, glucagon-like peptide 1, rat / Includes bibliographical references. / Diana L. Williams, Professor Directing Thesis; Lisa A. Eckel, Committee Member; Pamela K. Keel, Committee Member.