PS: Introduction to Psycholinguistics Winter Term 2005/06 Instructor: Daniel Wiechmann Office hours: Mon 2-3 pm Phone: Web:

Session 5: Understanding the structure of syntax  Task: Parsing Assign syntactic structure to incoming string of words Peter gave Mary the book N V N Det N S [ NP [N] VP [V NP [N] NP [Det N]]]

Session 5: Understanding the structure of syntax  How does parsing operate?  Why are some sentences more difficult to parse than others?  What happens to the syntactic representation after parsing?  How many stages of parsing are there?

Session 5: Understanding the structure of syntax  What happens if there is a choice of possible structures at any point?  At what stage is non-structural information information used?  Is there an enclosed (autonomous) syntactic processor (module)?

Session 5: Understanding the structure of syntax  Assumptions: Our knowledge of Grammar (and, therefore, phrase structure) provides us with “templates” for sentence structure As we hear sentences, we assign incoming words to phrases and phrases to nodes in these templates

Session 5: Understanding the structure of syntax  Psycholingists usually represent the parsing process as the on-line construction of PS- trees S -> NP + VP NP -> (Det) + N VP -> V + (NP)

Session 5: Understanding the structure of syntax  Early ideas about parsing (Fodor, Bever, and Garrett, 1974) First, we identify words on the basis of perceptual data Recognition and lexical access give access to syntactic category of a given word We then use this information to build up a parse tree for each clause Finally we use parse tree to generate semantic representaion

Session 5: Understanding the structure of syntax  Incremental parsing: Language processor operates incrementally, i.e. it rapidly constructs a syntactic analysis for a sentence fragment, assigns it a semantic interpretation, and relates this interpretation to world knowledge

Session 5: Understanding the structure of syntax  Standing syntactic ambiguity I saw the Alps flying to Romania Peter said that Mary finished it yesterday

Session 5: Understanding the structure of syntax  Local syntactic ambiguity The log floated past the bridge sank The old man the boats Since Jay always jogs a mile seems like a very short distance to him

Session 5: Understanding the structure of syntax  Kimball (1973) Structures are built guided by rules that are based on that are based on psychological constraints such as minimizing memory load

Session 5: Understanding the structure of syntax  Kimball (1973): Seven principles Top-down-parsing (predict constituents) Right association New nodes Two nodes Closure Fixed structure Processing

Session 5: Understanding the structure of syntax  The sausage machine (Frazier and Fodor 1978) Two-stage model  Preliminary phrase packager (PPP)  Sentence structure supervisor (SSS) later became the garden path model (Frazier 1987) Minimal attachment  Late closure

Session 5: Understanding the structure of syntax  Garden Path model: Minimal attachment Interpret sentences as having the simplest possible sturcture Late closure Interpret incoming word as part of the node under current construction  Peter found the book in library.  Peter found the book was the best book he ever read

Session 5: Understanding the structure of syntax  Constraint-based models of parsing Processor uses multiple sources of information (syntactic, semantic, frequency-based) Construction that is most strongly supported is most activated (and is usually the only to reach the level of consciousness) Garden paths occur when the correct analysis receives little activation („The old man the boat“)