Sentence Processing III Language Use and Understanding Class 12

Announcements Coming up: Coming up: Wed: Development of Procesing Abilities Wed: Development of Procesing Abilities Next Mon: Rules vs. Probabilistic approaches Next Mon: Rules vs. Probabilistic approaches Next Wed: Midterm Next Wed: Midterm Midterm will be all short answer/ essay Midterm will be all short answer/ essay You’ll get a superset of questions to study from on Wednesday You’ll get a superset of questions to study from on Wednesday

Previous models of parsing Garden Path model Garden Path model Encapsulated syntactic parser Encapsulated syntactic parser Choose the simplest syntactic structure when input is ambiguous Choose the simplest syntactic structure when input is ambiguous Make decisions based ONLY on category information from words, no plausibility information Make decisions based ONLY on category information from words, no plausibility information Referential Hypothesis Referential Hypothesis Try to pick a unique referent in context when available Try to pick a unique referent in context when available Otherwise pick simplest structure Otherwise pick simplest structure

Constraint-based models (MacDonald et al., 1994; Tanenhaus and Trueswell, 1994) Information from multiple sources impacts parsing decisions Information from multiple sources impacts parsing decisions Referential information Referential information Lexical information Lexical information What subcategorization frames are more frequent? What subcategorization frames are more frequent? Plausiblity information Plausiblity information Choices in syntactic frames involve choices in thematic (subcategorization) frames. Which frame allows a plausible thematic role for a given referent? Choices in syntactic frames involve choices in thematic (subcategorization) frames. Which frame allows a plausible thematic role for a given referent?

All models Sentence processing is incremental Sentence processing is incremental Garden-path model: you pick one structure early on, later have to revise if it isn’t the right one Garden-path model: you pick one structure early on, later have to revise if it isn’t the right one Referential model: use pre-existing context if available Referential model: use pre-existing context if available Constraint-based model: use constraints that are availble at the time of a parsing decision Constraint-based model: use constraints that are availble at the time of a parsing decision In no case is it proposed that the parser waits to solve indeterminacies In no case is it proposed that the parser waits to solve indeterminacies

Tanenhaus et al Referential Context Put the apple on the towel in the box. Put the apple on the towel in the box goal referent garden-path goal

Put the apple on the towel in the box. Sensitivity and time course in sentence processing:

Put the apple (that’s) on the towel in the box. Multiple referents eliminate the goal garden-path

Put the apple (that’s) on the towel in the box. 1.0 One-Referent Context Ambiguous Unambiguous Proportion of Trials with Eye Movements to Incorrect Goal Instruction Multiple referents eliminate the goal garden-path

Put the apple (that’s) on the towel in the box. One-Referent Context Ambiguous Unambiguous Proportion of Trials with Eye Movements to Incorrect Goal Instruction Two-Referent Context No garden-path with two potential referents

The influence of non- syntactic information Plausibility Plausibility The historian read the manuscript The historian read the manuscript …during the trip. …during the trip. …had been destroyed in the fire. …had been destroyed in the fire. How likely is it for a manuscript to be the object of read? How likely is it for a manuscript to be the object of read? How likely is it for a manuscript to be the subject of another clause? How likely is it for a manuscript to be the subject of another clause?

The influence of non- syntactic information Verb subcategorization Verb subcategorization Read: He read the book. He read Read: He read the book. He read He read that it had rained. He read that it had rained. Which is more frequent? Which is more frequent?

Garnsey et al. Verb bias: DO-biased verbs (direct object): read SC-biased verbs (sentential complement): accepted EQ-biased verbs (both): regretted The senior senator regretted (that) the decision had ever been made public. The senior senator regretted (that) the reporter had ever seen the report.

Models What does a two-stage model predict? What does a two-stage model predict? What does lexical filtering predict? What does lexical filtering predict? What does the constraint-based model predict? What does the constraint-based model predict?

Discussion The authors repeatedly discuss how verb bias may be the generally more effective constraint (as opposed to plausibility), as it is more readily accessible, and/or based on more experience, and/or more constraining. If this is so, would this affect the set up of the model? Obviously the model would still be interactive and constraint-based, but if it could be conclusively shown that verb bias is always the more important constraint, would it alter the model (i.e. having plausibility play a less central role, or not until slightly later on in the process)?