Constituency: heads and dependents
As we saw in Chapter 17, heads are described as profile determinants in Cognitive Grammar and the head-dependent relation is characterised in terms of conceptual autonomy and dependence. This view is consonant with the formal view in a number of ways. In particular, both models hold that the head or profile determinant lends its features to the phrase that contains it. The difference, of course, is that in Cognitive Grammar the features of the head relate to its schematic meaning (e.g. PROCESS or THING), while in formal approaches the features of the head relate to its grammatical category (e.g. V or N), which, as we have seen, is defined in structural rather than semantic terms. A second similarity between Cognitive Grammar and the formal approach relates to the metaphor of ‘dependency’ relations. In both models, the relationships between the component parts of a phrase are modelled in terms of dependence. Again, the difference lies in the fact that the Cognitive Grammar view of dependence relates to conceptual dependence, whereas the formal view relates to categorial selection. Of course, formal models also posit semantic selection in order to ensure, for example, that a verb like love selects an animate subject, but this process often operates independently of the grammatical component. This means that in the formal model of syntax, a head is entirely ‘autonomous’ within its phrase, in the sense that it selects all its dependents, some obligatorily (e.g. complement) and others optionally (e.g. modifiers). The Cognitive Grammar view is rather different: a head can be conceptually dependent on its ‘dependents’ if they elaborate some aspect of its structure. As we saw in Chapter 17, the head-complement construction illustrates this prototypical dependence relation. A further important difference follows from points that we have already discussed: in the cognitive model, constituency emerges from the properties of constructions, which are primitive. In the formal model, constructions emerge from ‘words and rules’, which are primitive.
