In an era where the diagnosis of attention deficit/hyperactivity disorder (ADHD) is as high as 7% in school-aged children, the search for causes and preventions has never been more important. Current research indicates a positive relationship between bilingualism, particularly native bilingualism, and executive function in normally developing individuals. This study served to examine the potential relationship between bilingual education in a public school setting and the presence of ADHD symptoms in that school's students. This was a comparative analysis of students in a South Florida School District's two-way immersion program with the national average in terms of frequency of ADHD symptoms using the NICHQ Vanderbilt Assessment Scale and the Swanson, Nolan, and Pelham (SNAP). The results did not show any significant differences between groups in terms of language history, gender, race, or family structure.

Most children discontinue daytime napping by the age of five. This study investigated the role of nap status and gender in executive functioning of Korean four-year olds, about half of whom have transitioned out of naps. Thirty-seven children living in the Gyeonggi-do area in South Korea participated in this study. A sleep diary filled out by parents was used to identify their nap habits and their executive function was assessed using the Fish Flanker Task involving three phases (standard, reverse, mixed). Looking at speed, reaction-time analyses suggested that girls take longer to warm up on the standard flanker task compared to boys a difference that diminishes by the next phase when children encounter the reverse flanker task. Looking at accuracy, children were slow to warm up. Although there were no differences in initial exposure to the standard flanker task, children were more accurate on congruent than incongruent trials in the the mixed phase regardless of nap status or gender. When shifting from the standard flanker to the reverse flanker task, habitual nappers were more accurate on incongruent trials in the reverse-flanker task compared to non-habitual nappers. There were no statistically significant differences in duration of nighttime sleep for habitual and non-habitual nappers supporting the idea that the advantage in accuracy on incongruent trials for habitual nappers was due to the nap. The results suggest that four-year olds may still receive a cognitive benefit from habitual naps, especially when they must shift between tasks.

The cognitive aging literature contains abundant evidence of the natural vulnerability of the frontal areas of the brain and the associated impact on higher-order cognition. Namely, Executive Functions (EFs) have been repeatedly shown to decline steadily after 60 (Schaie, 2013). These age-related changes are said to impact most aspects of everyday life including quality of life (QoL; Davis et al., 2010), a key variable with regards to health, social service interventions and evidence-based clinical practices. Deepening our understanding of potential moderators of cognitive aging such as QoL is crucial to promoting well-being in the growing older adult population. The overarching aim of this study was to investigate the moderating role of QoL over age-related EFs differences. A seminal taxonomy of EFs (Miyake et. al, 2000, 2012) and the work of the World Health Organization (WHO) on QoL (Power et al., 2005) inspired this endeavor. Six tasks of EFs related to Shifting, Updating, and Inhibiting and self-reported QoL based on the WHOQOL-BREF and -OLD were utilized with 102 community-dwelling, healthy older adults (M = 73.11 years; age range: 60 - 94). A moderation analysis was used to assess if QoL (moderator) buffers the relationship between age (IV) and EFs indicators (DV). Regression and MANCOVA analyses were conducted to evaluate age-related differences in EFs and the following prominent theories: the processing speed theory (Salthouse, 1996), inhibition deficit theory of cognitive aging (Hasher & Zacks, 1988), and dedifferentiation hypothesis (Garrett, 1946). As predicted, age significantly contributed to task performance for most EFs indicators, above and beyond processing speed. As expected, statistically significant moderation interactions were found for several executive indicators and QoL domains, illustrating the buffering role of QoL over age-related differences in EFs. Specifically, QoL items related to the environment, sensory abilities, and social engagement domains, and EFs indicators related to Inhibiting, showed the most notable moderating effects. Implications for these results and the role of covariates were discussed. An emphasis was placed throughout on the importance of investigating QoL variables and other moderating factors of cognitive aging, for the development of prevention and intervention endeavors with older adults. / Graduate

Few studies have researched writing difficulties in individuals with Autism Spectrum Disorder (ASD) and the factors responsible for such difficulties. The current study sought to examine writing difficulties in individuals with ASD and the contribution of working memory (WM) difficulties. The investigation consisted of five youth formally diagnosed with ASD (under DSM-IV-TR, higher functioning Autistic Disorder or Asperger’s Disorder), and five youth with no formal diagnosis. Participants completed a counterbalanced battery of tests that assessed their written expression and WM abilities. Due to challenges in recruiting enough participants for purposes of quantitative research, the study mainly used a case-study analysis. The study showed that participants with ASD (group with ASD) had more difficulty with writing and WM tasks than participates without ASD (traditionally developing [TD] group). Nonparametric analyses revealed that writing and WM were not related; however, these findings are cautionary due to very low participation numbers in the investigation. Case-study analysis showed that the group with ASD had underdeveloped writing skills notably in the areas of word count, vocabulary, spelling and grammar. Regarding WM abilities, the group with ASD showed variable patterns of difficulty; some had strengths in verbal WM while others did not. Unfortunately, the study could not determine if writing difficulties were specific due to WM or other causes, although it does provide useful information for further investigation. Additional studies investigating the relationship between writing and WM, particularly in individuals with ASD, are encouraged. / Graduate

Psychopharmacological studies have implicated the mesolimbic dopamine (DA) system in the mediation of cost/benefit evaluations about effort-related costs associated with larger rewards. However, the role of DA in risk-based decision making remains relatively unexplored. The present study investigated how systemic manipulations of DA transmission affect risky choice assessed with a probabilistic discounting task. Over discrete trials, rats between two levers; a press on the “small/certain” lever always delivered one reward pellet, whereas a press on the other, “large/risky” lever delivered four pellets, but the probability of receiving reward decreased across the four trial blocks (100%, 50%, 25%, 12.5%). In separate groups of well-trained rats we assessed the effects of the DA releaser amphetamine, as well as receptor selective agonists and antagonists. Amphetamine consistently increased preference for the large/risky lever; an effect that was blocked or attenuated by co-administration of either D₁ (SCH23390) or D₂ (eticlopride) receptors antagonists. Blockade of either of these receptors alone induced risk aversion. Conversely, stimulation of D₁ (SKF81297) or D₂ (bromocriptine) receptors also increased risky choice. In contrast, activation of D₃ receptors with PD128,907 induced risk aversion. Likewise, D₃ antagonism with nafadotride potentiated the amphetamine-induced increase in risky choice. Blockade or stimulation of D₄ receptors did not reliably alter patterns of choice. These findings indicate that DA plays a critical role in mediating risk-based decision making, where increased activation of D₁ and D₂ receptors biases choice towards larger, probabilistic rewards, whereas D₃ receptors appear to exert opposing effects on this form of decision making. / Arts, Faculty of / Psychology, Department of / Graduate

Introduction: The cognitive benefits of physical activity and sport on executive function are of interest to researchers, especially considering the subsequent interventions that could be implemented. However, researchers frequently use different approaches to conceptualize and measure executive function, often using only a few computerized tasks. My Master’s thesis, therefore, aims to investigate the associations between executive function and physical activity and sport through two different studies to obtain a robust evaluation of executive function: 1) A quantitative study examining physical activity, sport and concussion history in university students and their effect on executive function, and 2) A qualitative study exploring the executive functions engaged during a game from elite university athletes’ experiences. Methods: Quantitative Study. Canadian university students (n=247) completed an online study with nine computerized executive function tasks and a behavioural self-report of executive function, as well as questions assessing weekly physical activity, athletic status, and concussion history. Structural equation modelling and linear regression were conducted to predict executive function based on age, sex, physical activity, athletic status and concussion history. Qualitative study. Canadian university athletes (n=19) participated in semi-structured interviews via Zoom to determine the executive functions engaged during a game. Thematic analysis was used to analyze the interview transcripts. Results: Quantitative Study. The three-factor model of executive function had an overall good fit: χ2 = 66.38, df = 51, p = 0.07, CFI = 0.95, TLI = 0.93, RMSEA = 0.04 [90% CI: 0.00–0.06], SRMR = 0.05. No direct relationship was found between the factors and age, physical activity, concussion history, or athletic status. Sex was significantly related to inhibition, b = 0.52, p = 0.02, such that males had greater inhibition. Physical activity (b = 0.09, p < .01), concussion history (b = 3.29, p < .05) and athletic status (b = -4.01, p < .05) were found to be significant predictors in the regression predicting self-reported executive functioning. Qualitative study. Three themes were generated: 1) Engaging in pre-play or pre-game planning, organization and decision making, 2) Engaging in mid-play problem solving and purposive action and 3) Engaging in post-play or post-game information processing, emotional control and effective performance. Conclusions: The quantitative study found that physical activity, athletic status and concussion history were predictive of subjective but not objective executive function. The qualitative study determined that athletes engage many executive functions that are dependent on the timing of both the play and the game (pre-, mid- or post-). Real-life behavioural manifestations of executive functioning are more challenging to assess and measure but may be better predicted by and relate to life factors such as physical activity and sport participation. The results of my thesis provide support for future research to utilize and develop more unique and ecologically valid methods of measuring EF in the field of physical activity and sport. / Graduate

Learner mobility and active school travel (AST) has been proposed to improve school attendance and academic performance. In South Africa, approximately 86% of learners have been reported as walking to and from school. AST in Africa is becoming less common in urban areas, and this may be a contributing factor to the increased risk and frequency of noncommunicable diseases due to decreased physical activity. The aim of this wait-list controlled evaluation was to assess the physiological and cognitive changes of access to a bicycle versus walking on adolescents. Specifically, changes adolescent's physical activity levels and executive function in a South African low-income community. Two schools were recruited, with the evaluation school receiving bicycles and the control a school who were yet to receive bicycles. Significant differences were observed across the physiological and executive function assessments. Most notably in the executive function tests, the evaluation group showed significant time to completion decreases across all three tests (N-Back, Arrow Flanker, WCST: p< 0.001). The results from this study are significant, as they are the first to assess anthropometric, physiological and executive function in South African adolescents from low-socioeconomic regions. It is evident that there are potential improvements in working memory, inhibition and shifting due to cycling as a mode of AST or during leisuretime. Further research needs to determine the specific mechanisms associated with these improvements.

While Attention-deficit/hyperactivity disorder (ADHD) is one of the most common psychological disorders diagnosed during development, adult ADHD remains vastly under recognized and undertreated. In an effort to better understand current issues with adult ADHD assessment, this study examined the relationship between symptoms, impairment, and executive functioning. Results indicate that among individuals who screened negative for ADHD, those higher in executive function reported experiencing significantly less impairment than those lower in executive function. Executive function was shown to have a negative relationship with impairment and ADHD symptomology was shown to have a positive relationship with impairment. Additionally, impairment was significantly predicted by ADHD symptoms and executive function, and there was a significant interaction between executive function and ADHD symptoms in predicting impairment. Understanding the relationship between executive function, ADHD symptoms, and impairment is critically important in better understanding adult ADHD.

Autism Spectrum Disorder (ASD) is a complex neurologically based developmental disorder that can affect an individual’s thinking, feeling, language development and social interactions. The prevalence of ASD in the United States continues to rise and today is identified in approximately 1 in 68 children. The symptoms of ASD interfere with and limit everyday functioning (Centers for Disease Control, 2015), which results in the majority of individuals with ASD remaining dependent on caregivers in the areas of education, habitation, and recreation (Billstedt, Gillberg, and Gillberg, 2005 & 2011). There is growing evidence that executive dysfunction may contribute to the social, cognitive and functional deficits observed in individuals with ASD; however, there is a significant lack of evidence based interventions that address executive functioning skills for emerging adults with ASD. The EFFECT program was developed to address this identified need. It is an 8-week comprehensive program based on research, that facilitates activities of daily living and instrumental activities of daily living by addressing underlying executive functioning skills. A thorough literature review, methods for program implementation, funding, dissemination and program evaluation are described. / 2018-03-03T00:00:00Z

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