Date of Award
Doctor of Philosophy (PhD)
Michael C. Mozer
Young children often struggle to accomplish their intended goals in a self-directed way, without instructions or reminders from adults. Although it is clear that the ability to meet goals without external direction emerges slowly across development, little is known about the cognitive processes that might support these improvements, and whether certain experiences might be more effective in facilitating emerging self-direction than others. Chapters 2 and 3 in this dissertation explore relationships between children’s time in adult-structured activities, where they have fewer opportunities to decide what they will do, and their performance on a measure of self-direction in a task where few reminders are given, semantic verbal fluency (VF). Chapter 2 finds that 6- and 7-year-old children who spend more time in less-structured activities show better self-directed switching performance in VF, relative to children who spend more time in adult-structured activities. Structured activities, including adult-led lessons, homework, and chores, showed a trend-level negative association in the opposite direction, such that more time in structured activities predicted worse switching performance. Chapter 3 replicates and extends findings from Chapter 2 by investigating relationships between VF and two measures of environmental structure in a genetically-informative longitudinal twin sample. In independent phenotypic models, twins who lived in more structured homes and participated in more structured activities at ages 3 and 4 showed worse, and marginally worse VF switching performance at age 7, respectively, controlling for earlier VF ability and concurrent levels of environmental structure. At the same time, children who showed better VF performance at age 4 were more likely to participate in structured activities at age 7. These relationships persisted in models controlling for general cognitive ability, vocabulary knowledge, and socioeconomic status. Links between early structure and later VF were mediated by nonshared environmental factors (consistent with causal explanations), whereas links between early VF and later structure were mediated by nonshared and shared environmental factors, reflecting the possible influence of a passive gene-environment correlation. Chapter 4 focuses on the cognitive processes underlying production in semantic VF via the development of a computational model demonstrating how experience-dependent abstract representations may aid children’s word production. Chapter 5 concludes with a discussion of limitations, open questions, and future directions.
Barker, Jane Elizabeth, "How Do Children Begin to Engage Executive Functions in Self-directed Contexts? Modeling Environmental, Genetic, and Cognitive Processes Supporting Semantic Verbal Fluency" (2017). Psychology and Neuroscience Graduate Theses & Dissertations. 128.
Available for download on Saturday, December 21, 2019