<p>I examined the development of sensitivity to two fundamental aspects of Western musical pitch structure, key membership and harmony, which can be acquired without formal training. In Chapter 2 (Experiment 1), I describe the novel and engaging behavioural task that I designed in order to study a younger age group than in previous research. On each trial, children watched videos of puppets playing unfamiliar piano melodies and chord sequences, in which one puppet’s music conformed to Western pitch structure and the other’s did not. Children judged which of the two puppets played the best song. Five-year-olds demonstrated sensitivity to key membership but not harmony, whereas 4-year-olds demonstrated sensitivity to neither. However, event-related potential (ERP) responses to a subset of the stimuli (Experiment 2) showed evidence of implicit sensitivity to both key membership and harmony in 4-year-olds. These components differed from the typical response elicited in older children and adults, but were consistent with other studies showing similar immature components in young children. In Chapter 3, I found that 4- and 5-year-old children demonstrated behavioural sensitivity to both key membership and harmony in a less demanding task than was used in Chapter 2, specifically, in a familiar song. In Chapter 4, I compared children who were or were not taking music lessons and found that musical experience accelerated enculturation to musical pitch structure. Together, these findings indicate that under some circumstances even 4-year-old children demonstrate behavioural sensitivity to Western musical pitch structure, that implicit processes show sensitivity to Western musical pitch structure before this knowledge is demonstrated behaviourally, and that intensive musical experience accelerates musical acquisition.</p> / Doctor of Philosophy (PhD)