Learnability and feedback.
Peter C. Gordon · Developmental Psychology · 1990
Bohannon and Stanowicz (1988) have claimed that contrary to popular belief, children do receive negative evidence about the ungrammaticality of their utterances in the form of recasts, expansions, and repetitions. Bohannon and Stanowicz argue that given such negative evidence, learnability theory shows that natural languages can be learned and that there is no need to postulate innate knowledge based on such arguments. The present article establishes what exactly the claims of learnability theory really entail, and demonstrates that because Bohannon and Stanowicz have shown only partial negative evidence, the results have no bearing on existing formal proofs of learnability; also, the learnability proofs proposed by Gold (1967) actually tell us very little about what may or may not be innate. Finally, it is pointed out that there are cases of language acquisition in which feedback does not appear to occur.