Biology, culture, evolution and the cognitive nature of sound systems

Abstract

This paper reviews the importance of the interaction between cultural evolution, biological evolution and individual cognition in understanding the cognitive nature of speech sound systems. Because of the effect of cultural evolution, typological properties of languages do not reflect individual cognitive mechanisms directly. In addition, the interaction between cultural evolution and biological evolution deeply influences what kind of cognitive adaptations to speech can evolve.Theoretical work and computer simulation have shown that at least two kinds of adaptations to speech and language can evolve. One consists of weak biases to discrete features of language (such as word order) that convey a functional advantage. The other consists of stronger adaptations involving continuous traits in which language and biology can co-evolve (the vocal tract being a possible example of such a co-evolved adaptation). Experimental work is underway to identify how exactly cultural and biological evolution interact in human speech and language, and what cognitive mechanisms (if any) may have undergone selective pressure related to speech and language.The paper reviews a number of studies that take the evolutionary perspective, focusing notably on agent-based computer simulations and on experimental work that simulates evolution in the laboratory or experimental work that investigates the interaction between individual learning behavior and cultural transmission directly. The paper argues that taking the evolutionary perspective (both cultural and biological, as well as their interaction) into account is necessary for a full understanding of the cognitive nature of language and speech.