Naturally, alternative structures lead to alternative meanings, as the above examples show, and so structural disambiguation is essential. The problem is exacerbated by ambiguities in the meanings and discourse function even of syntactically unambiguous words and phrases, as discussed below (section 4). But here we just mention some of the structural preference principles that have been employed to achieve at least partial structural disambiguation. First, some psycholinguistic principles that have been suggested are Right Association (RA) (or Late Closure, LC), Minimal Attachment (MA), and Lexical Preference (LP). The following examples illustrate these principles: