[chilepepper]

The subcategorization rules can be assigned to the lexical component of the base in the following way. First of all, the context-free subcategorization rules can be regarded as suntactic redundancy rules, and hence assigned to the lexicon. Consider, then, the rules that introduce contextual features. These rules select certain frames in which a symbol appears, and they assign corresponding contextual features. A lexical entry may be substituted in these positions if its contextual features match those of the sumbol for which it is substituted. Obviously, the contextual features must appear in lexical items. But the rules that introduce contextual features into complex symbols can be eliminated by an appropriate reformulation of the lexical rule, that is, the rule that introduces lexical items into derivations.

So that's what's going on in an infant's brain when they are looking at their mother!