Statistical Evolutionary Laws in Music Styles

TL;DR

This paper uncovers statistical laws governing the evolution of music styles, demonstrating that an evolutionary model based on statistical learning can predict changes across different musical cultures.

Contribution

It introduces an evolutionary model that explains and predicts the statistical evolution of music styles, validated on Western classical and Japanese enka music data.

Findings

Distributions of rare musical events show increasing mean and standard deviation over time.

The model reproduces observed statistical laws of musical evolution.

The model predicts evolution patterns in different musical cultures.

Abstract

If a cultural feature is transmitted over generations and exposed to stochastic selection when spreading in a population, its evolution may be governed by statistical laws and be partly predictable, as in the case of genetic evolution. Music exhibits steady changes of styles over time, with new characteristics developing from traditions. Recent studies have found trends in the evolution of music styles, but little is known about their relations to the evolution theory. Here we analyze Western classical music data and find statistical evolutionary laws. For example, distributions of the frequencies of some rare musical events (e.g. dissonant intervals) exhibit steady increase in the mean and standard deviation as well as constancy of their ratio. We then study an evolutionary model where creators learn their data-generation models from past data and generate new data that will be socially selected by evaluators according to the content dissimilarity (novelty) and style conformity (typicality) with respect to the past data. The model reproduces the observed statistical laws and can make non-trivial predictions for the evolution of independent musical features. In addition, the same model with different parameterization can predict the evolution of Japanese enka music, which is developed in a different society and has a qualitatively different tendency of evolution. Our results suggest that the evolution of musical styles can partly be explained and predicted by the evolutionary model incorporating statistical learning, which can be important for other cultures and future music technologies.