By Maryna Mullerman ‘20

A conventional view that humans acquired language skills solely through biological evolution was challenged by Bart de Boer and Bill Thompson, researchers from the Max Planck Institute for Psycholinguistics in the Netherlands. Their study proposed a mathematical model in which biology and culture played important roles in language acquisition within finite populations. This alternative view argued that biological adaptation changes varied with population size and cultural change rates.

The model analyzed an abstract biological population with the ability to acquire a cultural trait. Bart de Boer’s model was based on the Moran process that illustrated change in finite populations with two competing variants. The population was assumed to have generalists, individuals with the ability to acquire either language equally well, and specialists, individuals that could acquire one language better than the other. The preferred cultural state was the one in which specialists were better. The researchers analyzed the likelihood of the shift and its speed in generalist population dynamics with an introduction of a single mutant specialist. The model focused on the rate of cultural change and the amplification of cultural evolution.

A culture with two alternating states lowered the probability that specialists could take over a generalist population. The amplifying forces affecting the dynamics were the specialist proportions and the time spent in the preferred cultural state. The proposed co-evolution model suggested that once specialists were introduced, the community would spend more time in the preferred state, giving fitness advantages to specialists. This would affect fixations of biological adaptation to culture.

Bart de Boer and Bill Thompson introduced a new model that enhanced the understanding of the role of biological and cultural co-evolution in human language acquisition. The researchers showed that in a finite population with a fluctuating culture, biological adaptations to culture can become fixed, amplified by an increasing socialist presence. This model is relevant to studies in linguistics and sociobiology, but it does not account for many aspects of diversity in real linguistic populations. Future research can focus on specific cultural evolution factors that help humans acquire language skills.

References:

1. B. de Boer, et al., Biology – Culture co-evolution in finite populations. Scientific Reports 8, (2018). doi: 10.1038/s41598-017-18928.
2. Image retrieved from: https://pixabay.com/en/school-board-languages-blackboard-1063556/