The aim of this dissertation was to explore whether preschoolers understand that preferences differ over time and between people. The first goal was to determine if 3-, 4-, and 5-year-olds could appreciate that their future or “grown-up” preferences may differ from their current ones (self-future condition). This understanding was compared to children’s understanding of the preferences of a grown-up (adult-now condition), or the grown-up preferences of a same-aged peer (peer-future condition). Results from 3 experiments (N = 240) suggest that these types of reasoning develop substantially over the preschool years, and that children are generally proficient by 5 years of age. Results also indicate that thinking about one’s own future preferences is more difficult than thinking about the (future) preferences of others. The second goal of this dissertation was to explore the relations between reasoning about preferences and theory of mind (ToM) and executive function (EF) abilities. Correlational analyses revealed that children’s reasoning about their future preferences and those of others was associated with EF skills, but not with ToM. These findings provide a timely contribution to the expanding research on children’s future-oriented cognition. Implications for theories about perspective-taking abilities, more broadly, and future research are also discussed.

The capacity to mentally project the self into the future or, what has recently been termed “episodic foresight” is an emerging topic of study in developmental psychology. The aim of this dissertation was to review available research on this topic and explore its development in two groups of children: typically-developing preschoolers and children with autism spectrum disorder (ASD). This dissertation had two main goals. The first goal was to explore whether tasks thought to measure episodic foresight in children are related and whether, as has been hypothesized, they were related to theory of mind (ToM) and executive function (EF). Study 1 showed that after controlling for age and language ability, episodic foresight tasks were not intercorrelated, nor were they individually related to ToM or EF tasks. Importantly, however, an episodic foresight composite score was related to several EF tasks. Specifically, the results suggested a significant relation between episodic foresight and inhibitory control. The second goal of this dissertation was to explore the development of episodic foresight in children with ASD. Specifically, I tested whether children with ASD would perform more poorly on a series of episodic foresight tasks than a mental-age matched group of typically-developing children. Study 2 revealed significant group differences on several episodic foresight tasks, suggesting that children with ASD showed impairments in thinking about themselves in the future. These results are a timely contribution to the research on episodic foresight and will hopefully aid in the further development of tasks that adequately measure this important cognitive ability in children.

Previous research has shown that alcohol abuse may cause a deficit in frontal lobe functioning, specifically, areas of the frontal lobe that are related to executive function. Additionally, problems with executive function have been related to increased difficulty in managing cravings to addictive substances. The current study explored the relationship between alcohol use and performance on measures of executive functioning in a sample of 121 traditional college students. Students were given 5 measures of executive function designed to explore mental set shifting, updating, inhibition, sustained attention, and planning. These measures were used to examine the relationship between executive function and craving as measured by the Obsessive Compulsive Drinking Scale. Levels of alcohol use were also examined using the Alcohol Use Disorders Identification Test in relation to executive function performance and family history of alcohol abuse.

Background: Children with chromosome 22q11.2 deletion syndrome (22q11.2DS) exhibit nonverbal learning disability that may manifest in part because of working memory (WM) deficits. 22q11.2DS is a complex developmental disorder with serious physical, learning, cognitive, and psychiatric symptoms including a risk of developing schizophrenia 30 times that of the general population. WM impairment likely contributes to and exacerbates learning difficulties, school problems, existing neuropsychological disorders such as attention deficit hyperactivity disorder (ADHD); and a poor WM may be a biological risk marker for future mental illness. WM impairment is established in this population, but less is known about its neurological origins. Frontoparietal cortical development and function are key to WM processing. In the neurotypical developing brain, studies indicate activation associated with WM shifts from parietal to frontal regions with age. However, in children with 22q11.2DS, activation is restricted to the frontal cortex, and volumes are reduced in parietal regions where abnormal tractography abides. The overarching aim of this study was to determine the neural origins of WM impairment in people with 22q11.2DS. Methods: We measured WM in children and adolescents with (n = 29) and without (n = 27) 22q11.2DS using the WISC-IV and a computer-based spatial working memory task (SWMT) task. Participants’ brains were scanned using high-resolution magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). Focusing on brain morphometry and structural connectivity within frontoparietal networks, we investigated neural underpinnings of WM processing in 22 children with 22q11.2DS and 19 typically developing (TD) controls ages 7 to 16 (M = 12.13 ± 2.41). A connectome mapping network involved in WM processing was constructed by superimposing cortical segmentations on white-matter tractography. Results: Children with 22q11.2DS had impaired working memory performance. Individuals’ performance on our SWMT moderated the association between diagnosis and gray and white matter macro and microstructure. Children with 22q11.2DS with better working memory had larger lateral orbitofrontal volumes, greater axial diffusivity in the left superior frontal to superior parietal tract, and smaller volume in the right superior frontal to lateral orbitofrontal tract. Poorer performance in children with 22q11.2DS was associated with smaller right superior parietal and superior frontal cortical volumes. Conclusions: Children with 22q11.2DS performed worse on measures of working memory. Their performance was related to regional cortical volume differences and white matter microstructure abnormalities in the frontal and parietal lobes. These are brain regions consistently implicated in WM processing.

The purpose of the study was to identify the effect of a single bout of moderately intense aerobic exercise on measures of executive function in young adults with ADHD. Thirty-two young adults between the ages of 18 and 25 years old were randomly assigned to either an acute exercise group or a control group. The exercise protocol was designed to address the methodological shortcomings in the exercise and executive function literature, and involved cycling on a stationary bike at moderate intensity for 30 minutes. Participants completed executive function tasks related to set shifting, working memory, and inhibition prior to and immediately following the treatment session. Results of the study reveal that acute exercise facilitated performance on the Stroop Color-Word task when compared to sedentary controls. However, unlike previous research on healthy adults, no improvements on the other measures of executive function were observed. These findings suggest that young adults with ADHD may specifically benefit from acute exercise on aspects of executive function related to the Stroop Color-Word measure. In conclusion, further research on this topic should continue to investigate this population, as well as consider the relationship between acute exercise and additional neuropsychological measures of inhibition, set shifting, and working memory in order to better determine the effects on each construct.

Controversy surrounds the idea that bilingualism leads to enhanced executive function (EF) and brain volume changes, potentially leading to delays in cognitive decline and dementia onset. The purpose of this research was to explore these claims in a sample of elderly monolinguals and bilinguals. This study explored gray matter volume (GMV) in 214 monolinguals and bilinguals (Mage = 71.21, SD = 7.53) who were cognitively normal (CN) or diagnosed with Mild Cognitive Impairment (MCI) or dementia. Neuropsychological performance was also examined between CN and MCI monolinguals and bilinguals (N = 153) across two visits. Scores from the Digit Span Backwards, Stroop interference, Trail Making Test A minus Trail Making Test B, and category fluency average scores were used. Magnetic Resonance Imaging (MRI) brain regions associated with memory, language, and EF were selected. Additionally, the study examined how a Bilingualism Index (BI) and the age of acquisition of English could predict GMV and EF in Spanish/English bilinguals whose native language was Spanish. Lastly, the initial age of cognitive decline across language groups was compared. Results suggested higher GMV in language and EF regions in bilinguals, but differences were not found in memory regions. Furthermore, neuropsychological performance over time did not vary across language groups; however, bilinguals exhibited reduced Stroop interference as well as lower scores on Digit Span Backwards and category fluency. The age of acquisition of English did not predict GMV or EF scores, while the BI predicted category fluency, with lower scores associated with a higher degree of balanced bilingualism. Overall, the influence of bilingualism appears to be reflected in increased GMV in specific language and EF regions relative to neuropsychological performance. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

Given the pathophysiology associated with the Human Immunodeficiency Virus (HIV) and the reported predilection for frontal circuitries and deep white matter, one might expect that executive dysfunction forms part of the neurocognitive profile of people living with HIV. However, such deficits have mainly been reported for adults living with HIV. Adolescence is a period where significant growth and refinement of executive functioning occurs and therefore specific research focused on HIV-positive adolescents is needed. Adolescence is also a developmental period where poor adherence to Antiretroviral Therapy (ART) persists despite marked increases in the national roll out of ART in South Africa, which has significantly decreased HIV-related morbidity and mortality rates. Poor adherence is not only a threat to the efficacy of ART but is also linked to the emergence of drug-resistant HIV strains and identified as a key contributor in the persistence of some cognitive impairments among people living with HIV. Studies show that executive dysfunction can undermine adherence to ART particularly in adolescents, whose frontal lobes are still developing. The first aim of this study was to compare the executive function profile of a group of HIV positive adolescents with that of a matched HIV negative control group. Using P. Anderson's (2002) model, executive functions were considered along the four subdomains: attentional control, processing speed, cognitive flexibility and goal setting. A second aim of the study was to investigate the relationship between executive function and levels of adherence to ART amongst the HIV positive adolescents in the sample. This cross sectional, between-groups study used a comprehensive neuropsychology test battery which was sorted into composite domains to investigate differences in executive functioning between the two study groups of adolescents aged between 14 to 16 (n = 22 in each group) using t-tests. Correlation coefficients were further computed to establish association between adherence and executive functioning. Apart from processing speed (p = 0.42, after the removal of outliers), there were no significant between-group differences in executive functioning outcomes that emerged between the HIV-positive and HIV-negative groups. The neuropsychological test scores for both groups were largely in the borderline range. Correlations between adherence and executive functioning outcomes did not yield any significant associations for each of the executive function domains. The lack of significant between-group differences may be explained by the mitigating effects of ART in the CNS in the HIV-positive group. However, consideration should be given to social factors as these may be important mediators of cognition and may therefore confound neuropsychological performance outcomes for both groups. Although the findings in the current study did not conclusively provide evidence for the role of executive functions in adherence, given the noted limitations, further studies with larger samples should confirm such outcomes.

The present study evaluated the associations between direct measures of aerobic fitness and executive functioning in pre-adolescent children aged 8 to 12 years. To evaluate these associations, the study employed a cross-sectional design and a series of three step hierarchical regressions were conducted. Results suggest that after controlling for age, sex, and BMI percentile, heart rate measures of aerobic fitness did not independently predict executive function. These findings provide preliminary evidence that contradicts a growing body of research within the adult literature demonstrating an association between aerobic fitness and executive function.

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Preschool years are an important period for executive function (EF) development. The two common ways of assessing EF in preschoolers are performance-based (PB) and rating measures. One of the most commonly used rating scales for preschoolers is the Behaviour Rating Inventory of Executive Function – Preschool Version (BRIEF-P). The current study explored the longitudinal relationship between three PB measures (Grass/Snow, Shape School, Self-ordered Pointing) and corresponding BRIEF-P scales (Inhibit, Shift, Working Memory) in typically developing preschoolers. There were three assessments in six-month intervals. Participants included 101 children at Time 1, with 86 and 75 in subsequent assessment time points. Using a latent variable approach, longitudinal measurement invariance was tested, supporting partial strong invariance. Results showed a lack of direct correlations between PB measures and corresponding BRIEF-P scales across time. These findings were interpreted in the context of existing literature, yielding a more nuanced understanding of what these two types of measures assess. Specifically, it is proposed that BRIEF-P measures children’s subjective, average level of EF, while PB tasks measure their objective, in-the-moment EF. / Graduate