43
3.2.3 The ‘Language Acquisition Device’ A classical ‘black box’ is a bounded entity, the contents of which are not specified. Writers postulate ‘black boxes’ solely in order to have something from and to which they can draw arrows. The arrows represent the sequences in which the writers think things happen, and so they serve as practical definitions of the boxes. Perhaps the best-known ‘black box’ in the study of language is the ‘Language Acquisition Device’ (LAD). The way Glucksberg and Danks (1975) introduce this metaphor to their readers is typical of how it has been treated by many other writers:
Glucksberg and Danks (1975)
cf.discussion in this chapter
‘[The] central feature of children’s speech [is that] it is systematic and rule governed.… The rules....are not taught explicitly, [but] must somehow be inferred or discovered by everyone [in learning his/her first language].
The arrow from ‘LAD’ in Glucksberg and Danks’ diagram leads to another box, marked ‘Grammar’.
For lack of an adequate understanding of how language might be learned. a mechanism for language acquisition has been postulated. This is the Language Acquisition Device.
‘a bounded entity, the contents of which are not specified’
‘[The LAD receives input from three sources.] Input 1 is the perception of the physical and social world, and input 2 represents the speech of the people of that world. Input 3 represents the child’s developing conceptual system. the LAD itself may be regarded as an integral part of that conceptual-cognitive system, or as a separate mechanism which can draw information from “cognition” and transmit information back.’ (emphasis added] ‘This description cannot be taken literally. Its only purpose is to highlight the kinds of interactions and relations involved in learning to understand and speak a language.’
(the second type of label in 3.1.3 above) Three arrows are drawn to the ‘LAD’ box.
Uncertainty on the important issue of boundaries is shown as a single, nonrectangular box around both ‘LAD’ and ‘Cognition’, with a wavy dotted line between the two areas and two arrows crossing that line, one in either direction. ‘This is a metaphor. Its purpose is to serve as a compact label for the above facts and relationships, and to add a bit to “clarity or vivacity of style.”’ (3.l.4).