Studies in Hungary, Australia, and the United States indicate an impact of Kodaly music training on perceptual, cognitive, and social development. This research has the following goals: a) to determine the effects of Kodaly musical training procedues on samples of early elementary school age children (K-3), spanning all socioeconomic levels, in terms of reading, mathematical, social, and musical skills (N equals 659); b) to determine which of the components and features of Kodaly music training are responsible for the effects; and c) to determine which of these components or features could be extracted for use in conventional instructional programs at this age level. The instruments used are standard tests and tests constructed by project personnel in order to establish direct logical linkages between components of both musical and nonmusical curricula. They are: a) reading readiness and achievement tests; b) mathematics achivement test constructed with items relating to logical operations -- measurement of physical time, ordering, seriation, etc.; c) classification tasks (cognitive, social, attitudinal); d) classroom interaction measures; e) music test (auditory discrimination) constructed for prereaders and readers; f) ratings of classrooms, materials, instruction, and teachers' logs.