A computer-assisted composition tool for investigating the application of
evolutionary techniques in the composition of music is presented. The nature
of such an application is examined in terms of defining the possible
mechanisms that provide a means for automated creativity. These mechanisms
take inspiration from processes found in Darwinian-based evolution theory,
genetic algorithm theory and similar aesthetically based uses of a genetic
search heuristic in the visual arts. A formal model of ‘musical
evolution’ is proposed, with particular emphasis placed on the ways
in which a genetic algorithm can be used to effectively manipulate a
variety of compositional structures within a hierarchical and generative
grammar-based model of musical composition. The result is a prototype
Windows MIDI application called GeNotator that allows composers to
experiment with a range of musical structures by interactively
‘evolving’ them through a familiar and comprehensive graphical
user interface.