Motivated Learning: The Influence of Reinforcers
Extant research suggests a number of systems, including reinforcement and attentional systems, contribute to learning. The overall goal of this dissertation is to expand our understanding of how reinforcement systems contribute to learning. Chapters 1 and 2 use a task-irrelevant learning paradigm, which has been used to study the role of reinforcement systems in learning. To first understand how reinforcement systems influence learning, Chapter 1 tests the hypothesis that task-irrelevant learning is mediated by the norepinephrine reinforcement system, by using pupillometry as an indirect measure of norepinephrine system activity. Consistent with this hypothesis results indicate an increased change in pupil size accompanying learning. Chapter 2 investigates how emotion stimuli, which are thought to activate distinct reinforcement systems than the norepinephrine system, influence learning. Consistent with this hypothesis, results indicate that learning, found to be influenced by the norepinephrine system, is moderated by emotion stimuli. Chapter 3 used a task-switching training task manipulating explicit feedback (i.e. points), to investigate how reinforcement systems influence learning in the executive function domain. Consistent with the hypothesis that reinforcement systems ‘tag’ task-relevant brain states, results indicate that feedback schedules which favored speeded responses, biased response strategies to sacrifice accuracy for speed. In conclusion, this dissertation furthers our understanding of the role of reinforcement systems in learning by providing a method of measuring norepinephrine reinforcement system activity during learning as well as provides a novel framework to understand how multiple reinforcement systems contribute to learning.