In today’s issue of Proceedings of the National Academy of Science, BEACONite Chris Adami comments on a research article by MacCallum, Mauch, Burt & Leroy on “The evolution of music by public choice.” Much like the digital evolution techniques used by many BEACONites, the authors used a computer program to evolve musical sounds via mutation and recombination. The successful sounds that contributed to the next generation were those selected by human listeners who found the sounds pleasing. Though the “musical appeal” measurement increased significantly in the early evolutionary stages, it quickly flattened out. Two traits that contributed to the music’s appeal – rhythmic complexity and chordal clarity – were highly correlated, and sexual recombination was likely breaking up these adaptive complexes, leading to the adaptation slowdown.
Adami explains that although this experiment may not tell us much about the way music actually evolves in human societies, it demonstrates that the fitness landscape metaphor and epistatic interactions between mutations are important both for understanding evolution on artificial landscapes as well as for predicting evolution in nature – for example, the predicted evolution of drug resistance in HIV.