The field of sentence parsing is currently blessed with intriguing theories of human sentence processing and with theorists who defend their theories with enthusiasm and dedication. This is far better than it was at the beginning of serious research into sentence parsing. The theory of derivational complexity was the best thing going, but it was a constantly moving target, whipping from one position to another as linguistic theory changed, and it always seemed possible to shoot it down wherever it went (see Gough & Diehl, 1978).

Things didn't get much better in the early 1970s, with the development of detective models of human sentence parsing (Fodor, Bever, & Garrett, 1914). Parsing theory was reduced to a list of “clues” that the parser might search for, and from which it might, in an associationistic fashion, project what kind of sentence it might be processing. Experimental research was dull, little more than the demonstration that this or that surface feature of sentences had something to do with comprehension (see Clark & Clark, 1977).

A turn for the better came in the mid-1970's with Kimball's principles (Kimball, 1973). Here were some explicit, economical statements of parsing preferences and decision rules that might have some broad applicability – something better than “look for a noun phrase after a transitive verb.” Frazier (1979) brought this approach to a new maturity with her proposal that a pair of strategies could account for a wide range of the phenomena that had previously been accounted for in only an ad hoc fashion.