The cultural evolution of distortion in music

Evolutionary theories of the origins and functions of music often fail to explain the remarkable diversity in music traditions around the world. Musical behaviour is the product of a multicomponent collection of abilities, some possibly evolved for musical behavior, but most derived from traits evolved for nonmusical reasons. Cultural evolution has stitched together these systems, generating variable normative practices across cultures and musical genres. Here, we describe the cultural evolution of musical distortion, a noisy manipulation of instrumental and vocal timbre that emulates nonlinear phenomena (NLP) present in the vocal signals of many animals. We suggest that listeners’ sensitivity to NLP has facilitated technological developments that have enhanced musical sound through specific distorted sonic manipulations, which further evolved culturally via the need for groups to both coordinate internally and differentiate themselves from other groups. To support this idea we present an agent-based model of norm evolution illustrating possible dynamics of continuous traits such as timbral distortion in music, dependent on i) a functional optimum, ii) intra-group cohesion and inter-group differentiation, and iii) groupishness for assortment and social learning. Overall we offer a preliminary account of how cultural transmission dynamics can lead to diversity in musical sounds and genres.