Biologically inspired and agent-based algorithms for music

For all of humankind’s creative achievements, we in turn were made by a more powerful creative force: biological evolution. Since Darwin and Wallace’s great revelation (Darwin, 1861), it has become widely accepted that the astonishingly beautiful and complex structure and behaviours of the living world have taken shape through a remarkable process that is mechanical, blind and purposeless. This sublime beauty has inspired art since its primitive beginnings, but whereas we have always incorporated natural form in our paintings, sculpture and music, artists working with code now draw upon processes of the natural world. The arrival of general purpose computers in the middle of the last century transformed not only science, but compositional practice in ways that are documented throughout this book. Of importance to this chapter, it enabled us to harness behaviours inspired by natural systems, formalised by biologists and computer scientists into algorithms, in order to develop, perform and compose with software instruments. We now borrow from the designs of specific biological organisms, and the properties and processes of complex natural systems, as well as from the creative mechanism of evolution itself. In this chapter we examine a range of approaches to algorithmic music making inspired by biological systems. In doing so we cover topics that are located at the intersection of contemporary music and computer science and the study of creativity: optimisation and problem-solving using evolutionary methods; emergence, self-organisation and complexity; adaptive behaviour; and autonomy and self-determination. Section 1.1 provides a brief historical context of the core intellectual, musical and social movements which influence contemporary creative practice. Section 1.2 provides a primer in the concepts and tools developed for the study of systems which are foundational to the specific approaches described in the following sections. Endeavours in this field are often hybrid and idiosyncratic and cannot be neatly categorised. Nevertheless we organise an overview of the key musical motivations, concepts and computational methods of the field under four themes which map the topics above. Section 2, Evolutionary Search, outlines the application of evolutionary computation to design issues and opportunities associated with algorithmic music. In Section 3, Multi-Agent Compositions, we look at the ways in which agent-based modelling has been used to compose emergent, self-organising music. Section 4, considers how the study of adaptive behaviour has inspired the design and realisation of Adaptive Collaborators – interactive software systems which begin to enable active electro-acoustic partnerships. Many of these ideas come together in Section 5, which describes the development of Creative Ecosystems inspired by ecological principles. We end with a discussion of some of the critical themes for future work.