What is significant is that this is essentially an elaboration of Figs. 7.1b and 7.1c: it provides a route in both directions
between sound and meaning, mediated by syntax and by the lexicon, where the lexicon is part of the interface
components.
Fig. 7.2 is of course an oversimplification. Among other things, it omits the interior tier structure of phonology, the
possible division of syntax into phrasal, morphosyntactic, and possibly grammatical function tiers, and the tiers of
conceptual structure to be motivated in Chapter 12. It also leaves open whether the interface processors are
bidirectional, or alternatively whether there is one of each for perception (left-to-right) and for production (right-to-
left)—an important issue that competence theory alone cannot decide (see Hagoort, Brown, and Osterhout 1999 for
discussion).
A crucial role in this processor is played by linguistic working memory. Some aspects of working memory were
introduced in section 3.5. In particular, several arguments were offered for why working memory must be a distinct
component, something beyond just the currently activated parts of long-term memory. In Fig. 7.2, linguistic working
memory is to be understood not just as a static storage space for linguistic material, but as a dynamic“workbench”or
“blackboard” on which processors can cooperate in assembling linguistic structures. It has three divisions or
“departments”or“buffers,”correspondingtothethreelevelsof linguisticstructure(alternatively, onecanthinkofitas
three functionally separate working memories—it is just a matter of terminology). We return to the character of this
component at several points in this chapter.
7.2 How the competence model can constrain theories of processing
Now it is possible to ask: To what extent does the logic of the competence theory dictate the logic of processing?
There may of course be constraints on processing that come from the way the processor is implemented in the
brain—and the competence theory will have nothing to say about these. Nevertheless, it is interesting to see how far
we can go by thinking about processing simply in terms of its logical structure.
In this spirit, here is a preliminary sketch of the course of language perception; we will elaborate on it as the chapter
goes on. In brief, one can think of the auditory input as“clamping”linguistic working memory at the phonological
end; the constraints then proliferate structure fro mphonology through syntax to se mantics. In slightly more detail:
The interface fro mthe auditory syste m