4.5 Language and communication

Language is the most distinctive human trait and a prime candidate for a complex adaptation. The evidence that it is an evolved instinct — rather than a mere cultural invention — is strong and worth examining carefully.

The language instinct

Noam Chomsky argued, and Steven Pinker popularized, that language is an instinct: a species-typical, specialized capacity that develops on a predictable schedule with minimal explicit teaching. Children acquire grammar rapidly, in a fixed sequence, and generate novel sentences they have never heard — making errors (like "goed" and "foots") that reveal they are extracting rules, not just imitating.

The poverty of the stimulus

A central argument is the poverty of the stimulus: the language children hear is too sparse and error-ridden to account for the rich, rule-governed grammar they acquire. The gap implies the child brings innate structure — a universal grammar — to the task. Learning fills in parameters; it does not build the system from scratch.

Design features and honest communication

Language has hallmarks of designed communication: it is digital (discrete words combined by rules), generative (infinite expressions from finite means), and displaced (it can refer to the absent, the past, and the hypothetical). But communication poses an evolutionary puzzle — why be honest? Signaling theory and the policing of reputation help explain why language is reliable enough to be useful.

A grounding example

Studies of creolization show language structure emerging in a single generation. When children are exposed to a pidgin — a makeshift, grammarless contact language thrown together by adults with no common tongue — they spontaneously transform it into a creole, a full language with consistent grammar, complete with tense, agreement, and word order that the pidgin lacked. Derek Bickerton documented this in plantation communities, and Judy Kegl observed it as deaf Nicaraguan children, given only crude home signs, generated a fully grammatical sign language on their own. Children do not just learn language; given impoverished input, they create its missing structure — exactly what an innate language faculty predicts.