Cultural selection for learnability: Three hypotheses concerning the characteristic structure of language

Here is a far-reaching and vitally important question for those seeking to understand the evolution of language: Given a thorough understanding of whatever cognitive processes are relevant to learning, understanding, and producing language, would such an understanding enable us to predict the universal features of language? This question is important because, if met with an affirmative answer, then an explanation for why language evolved to exhibit certain forms and not others must be understood in terms of the biological evolution of the cognitive basis for language. After all, such an account pivots on the assumption that properties of the cognitive mechanisms supporting language map directly onto the universal features of language we observe. We argue against this position, and note that the relation between language universals and any cognitive basis for language is opaque. Certain hallmarks of language are adaptive in the context of cultural transmission; that is, languages themselves adapt to survive by adapting to be learnable. Linguistics should explain why languages exhibit certain hallmarks and not others. In relation to this objective, the notion of cultural selection for learnability is far-reaching because,