Kimball's parsing principles (Kimball, 1973), Frazier and Fodor's Sausage Machine (Frazier and Fodor, 1978; Fodor and Frazier, 1980) and Wanner's augmented transition network (ATN) model (Wanner, 1980) have tried to explain why certain readings of structurally ambiguous sentences are preferred to others, in the absence of semantic information. The kinds of ambiguity under discussion are exemplified by the following two sentences.

1. Tom said that Bill had taken the cleaning out yesterday.

2. John bought the book for Susan.

For sentence (1), the reading ‘Yesterday Bill took the cleaning out’ is preferred to ‘Tom spoke yesterday about Bill taking the cleaning out.’ Kimball (1973) introduced the principle of Right Association (RA) to account for this kind of preference. The basic idea of the Right Association principle is that, in the absence of other information, phrases are attached to a partial analysis as far right as possible.

For sentence (2), the reading ‘The book was bought for Susan’ is preferred to ‘John bought a book that had been beforehand destined for Susan.’ To account for this preference, Frazier and Fodor (1978) introduced the principle of Minimal Attachment (MA), which may be summarized as stating that, in the absence of other information, phrases are attached so as to minimize the complexity of the analysis.

Much of the debate about the formulation and interaction of such principles is caused by their lack of precision and, at the same time, by their being too specific. I propose a simple, precise, and general framework in which improved versions of Right Association and Minimal Attachment can be formulated.