Indeterminacy in language acquisition: the role of child directed speech and joint attention

Language acquisition represents one of the great learning achievements in human cognitive development. Perhaps, this process takes place in a relatively automatic manner in which, simply through exposure to language input, the child configures her language organ to coincide with the structure of the maternal language. In this context, the problem of the vast uncertainty between speech input and its external referent, related to the more general notion of the ‘poverty of the stimulus’ problem, takes on a significant importance, and motivates the nativist suggestion that language is already essentially preprogrammed, and acquisition consists of setting the parameters for the target language based on limited exposure. What if, however, the acquisition process was not so automatic, but rather was controlled by the operation of mechanisms that could direct the attention of the child to specific aspects of the sentence and its external referent? In this case, external and internal control of attention could significantly reduce the referential uncertainty, thus reducing the requirement for preprogrammed language. The current paper outlines evidence for this second scenario, in which child directed speech guides the child’s attention to important aspects of the speech signal, and Joint Attention focuses his attention on the relevant aspects of the referential world, significantly reducing the poverty of the stimulus problem. Results from recent simulation studies are briefly reviewed that indicate how these mechanisms could then allow a relatively non-specific learning mechanism to acquire initial knowledge of grammatical constructions in the first steps of language acquisition. q 2003 Elsevier Ltd. All rights reserved.