1. Frazier & Fodor (1978) Goal –Explain why hard sentences are hard –And why structural ambiguities typically have the preferred resolutions they do –Entirely via the architecture of the processing system

2. Motivation for Architecture Human working memory is limited –7 +/-2 “items”? –Structural relationships among words in sentences often depend on more words than can be held unanalyzed in memory –So try to impose some phrasal chunking on words as they come in and get rid of them to make room for new words

3. Two-Stage Architecture Imposing at least some chunking helps manage demands on memory, so divide parsing over 2 stages to get some incomplete chunking done ASAP –Preliminary Phrase Packager (PPP) Can only see ~6 words at a time Tries to impose as much phrasal chunking on them as it can But may do it wrong because can’t see enough at once –Sentence Structure Supervisor (SSS) Puts phrases passed by PPP together into larger constituents Fixes mistakes made by PPP – How?

4. Example of Preferences to be Explained Tom said that Bill had taken the cleaning out yesterday. –Strong preference to attach adverb to most recent verb Tom said that Bill will take the cleaning out yesterday. –When the tense of the more recent verb makes it impossible to attach it to the more recent verb, given adverb meaning, the sentence is hard Because PPP can no longer see earlier verb by time adverb comes in

5. Another Example Joe bought the book that I had been trying to obtain for Susan. –Pref to attach PP to most recent verb –Because PPP can’t see earlier verb by then Joe bought the book for Susan. –Now pref to attach PP to more distant verb –Because can still see it, and …

6. Minimal Attachment When there’s a choice about how to attach incoming words –Choose the option that results in the simplest local structure –In Joe bought the book for Susan., That means attaching for Susan to bought rather than to the book

7. Desirable Properties Claimed for Model Elegance –Pref to attach incoming material locally is natural, inevitable consequence of PPP’s size limit –A single very general strategy, together with the size limit, explains preferences for many different examples of ambiguity Mix of bottom-up and top-down processes BUT …

8. Does it really account for all attachment preferences so simply? Tom said that Bill had taken out the cleaning yesterday. Tom said that Bill had taken it out yesterday. Tom said Bill took it yesterday. The last one should be within the PPP’s window, but there’s still a pref for the local attachment. So, NO (Wanner, 1980)

9. Fodor & Frazier (1980) Add a 2nd parsing principle to account for preferences not explained by just MA plus size limit –Late Closure = Attach words into the currently open constituent, if possible