Evolving Four Part Harmony Using a Multiple Worlds Model

This application of the Multiple Worlds Model examines a collaborative fitness model for generating four part harmonies. In this model we have multiple populations and the fitness of the individuals is based on the ability
of a member from each population to work with the members of other populations. We present the result of two experiments: the generation of compositions, given a static voice line, both in a constrained and unconstrained
harmonic framework. The remaining three voices are evolved using this collaborative fitness function, which looks for a number of classical composition rules for such music. The evolved music is found to meet with
the requirements placed on it by musical theory. Using the data obtained while running our experiments we observe and discuss interesting qualities of the solution space.