Mechanism (biology)

Gene

Linguistics

Demography

Philosophy

Bayesian probability

Biology

Analogy

Extinction (optical mineralogy)

Language evolution

Selection (genetic algorithm)

Computer science

Evolutionary biology

Cognitive science

Paleontology

Genetics

Genetic diversity

Psychology

Epistemology

Population

Sociology

Artificial intelligence

Genetic drift

Rule-based machine translation

Allele

Genetic variation

Natural selection

Proceedings of the Royal Society B Biological Sciences

Scientists studying how languages change over time often make an analogy between biological and cultural evolution, with words or grammars behaving like traits subject to natural selection. Recent work has exploited this analogy by using models of biological evolution to explain the properties of languages and other cultural artefacts. However, the mechanisms of biological and cultural evolution are very different: biological traits are passed between generations by genes, while languages and concepts are transmitted through learning. Here we show that these different mechanisms can have the same results, demonstrating that the transmission of frequency distributions over variants of linguistic forms by Bayesian learners is equivalent to the Wright–Fisher model of genetic drift. This simple learning mechanism thus provides a justification for the use of models of genetic drift in studying language evolution. In addition to providing an explicit connection between biological and cultural evolution, this allows us to define a ‘neutral’ model that indicates how languages can change in the absence of selection at the level of linguistic variants. We demonstrate that this neutral model can account for three phenomena: the s-shaped curve of language change, the distribution of word frequencies, and the relationship between word frequencies and extinction rates.

Words as alleles: connecting language evolution with Bayesian learners to models of genetic drift