Ambiguity avoidance in English relative clauses

Are syntactic choices influenced by the need to avoid ambiguity? Studies of the use of that with English embedded clauses have reached negative conclusions on this point. It is argued here that these conclusions may be premature. Statistical analysis of another phenomenon of English-use of the optional relative pronoun or complementizer with object relative clauses-in written text suggests that both AMBIGUITY AVOIDANCE and ANAPHORICITY contribute to syntactic choices. Ambiguity avoidance is shown to operate at a 'strategic' level, influenced by general considerations of syntactic structure, but not by lexical distinctions or pragmatic factors.