Introduction: Executive functions (EFs) are a set of inter-related neurocognitive abilities, recruited for top-down, conscious control of thoughts, actions and emotions. EFs develop rapidly during the preschool period (age 3 to 6 years), which is the same time, during which the symptoms of Attention Deficit/Hyperactivity Disorder (ADHD), namely hyperactivity, impulsivity, and inattention, become evident. Furthermore, hyperactivity, inattention, and the EFs contribute to academic performance once children begin formal schooling. To clarify the interplay of these processes, this dissertation conducted 3 studies that used a longitudinal design (4 time-points) to investigate the development of EFs from age 3 to 6 years, the relations between EFs and hyperactivity across this same period of time, and their relative contributions to inattention and academic performance at 6 years of age. Study One: Children’s performance on EF tasks was examined across 4 time points, beginning at 36-48 months of age. Results indicated significant between-child variability for all EF component processes at 3 years of age, significant growth over time, and preliminary support for the theory that, among EFs, working memory may develop first. Furthermore, EF performance at 3 years of age made significant contributions to performance on complex tasks of problem solving and planning at 6 years of age. Study Two: The aim of study two was to evaluate the relations between EF, hyperactivity, and inattention. Results indicated significant between-child variability in EF task performance, with a decrease in variability from age 3 to 4.5 years. Hyperactivity at age 3 years reliably predicted hyperactivity at 6 years of age for females, who also had lower hyperactivity scores. In contrast, for males, child EF performance and parent-report of EF at age 3 years were the best predictors of hyperactivity at 6 years of age. Study Three: The aim of study three was to expand upon the relations between EF, hyperactivity, and inattention by evaluating their relative contributions to academic performance. There were limited relations between academic performance, hyperactivity, and inattention. However, EF performance at 3 years of age predicted age 6 reading and math, whereas parent-report EF only predicted reading. Furthermore, hyperactivity at 4.5 years of age moderated the relation between age 3 performance EF and age 6 academic performance, with this relation becoming stronger as hyperactivity increased. Conclusion: Together, these studies make several notable contributions to the field: (a) that initial EF abilities at 3 years of age are highly variable between children, but improve consistently over time, (b) that the relations between hyperactivity and EF appear to be different for males and females (or higher/lower levels of hyperactivity), and (c) that even in a community sample, hyperactivity moderates the EF-academic performance relation. These findings contribute to the early identification of hyperactivity and interindividual differences in EF abilities, in very young pre-schoolers, who may go on to have more difficulty in a formal schooling setting. / Graduate / 2023-08-09
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/14094 |
| Date | 16 August 2022 |
| Creators | Graves, Abigail Reid |
| Contributors | Mueller, Ulrich |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Available to the World Wide Web |
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