Linguistic Capacity: An Ontogenetic Theory with Evolutionary Implications

Abstract

In this chapter, I will present a theory on the infant’s development of language that was inspired, in part, by research on non-human primates and other animals. According to the theory, long before infants speak or even know about the existence of linguistic rules and representations they store utterances and supporting contextual information. Utterance storage is carried out primarily by the right cerebral hemisphere, which is heavily involved in the processing of vocal intonation and affect at the time storage operations commence. Many of these prosodically organized utterances are reproduced, giving listeners the impression that the infant is using language. Lexical forms accumulate at a gradual rate until a point at which — for reasons not well understood — rate of word learning accelerates. The consequent proliferation of words threatens to overload the infant’s small capacity store for intonationally or prosodically organized material. Overloading is avoided by activation of a mechanism, typically sited in the left hemisphere, that analyzes utterances into their component parts. When infants discover the patterning of these units, they learn something about the organization of the ambient sound system. Organizational learning permits infants to compute novel word forms, the first evidence of grammatical behavior. While non-human primates seem unable to analyze and compute utterances in this fashion, they may be capable of preliminary operations that in the human appear to facilitate lexical acquisition and use.

What forces propel the young child into language use? After an unprecedented surge in research over the last two decades or so we are still no nearer to providing anything even approaching a definitive answer to this question (Schaffer, 1989).