Context Accommodation in Human Language Processing June 2010

1. Context Accommodation in Human Language Processing June 2010 Jerry T. Ball Senior Research Psychologist 711th HPW / RHAC Air Force Research Laboratory DISTRIBUTION A. Approved for public release; distribution unlimited.

2. Theoretical Alignment • Cognitive Linguistics • No autonomous syntax • Grammatical categories are semantically motivated • Construction Grammar • Constructions at multiple levels of idiomaticity • No sharp distinction between lexicon and syntax • X-Bar Theory • Prior to introduction of functional heads • Simpler Syntax • Flat syntax trees Distribution A

3. Theoretical FoundationsLanguage Representation and Processing • Double R Grammar • Cognitive Linguistic theory of the grammatical encoding of referential and relational meaning • Double R Process • Psycholinguistic theory of the processing of English text into Double R Grammar based representations • Double R Model • Computational implementation using the ACT-Rcognitive architecture and modeling environment www.DoubleRTheory.com Distribution A

4. Research Goals Develop models of Human Language Processing… • Functional • Use in real applications • Synthetic Teammate prototype • Cognitively Plausible • Adhere to well-established cognitive constraints • Don’t use computational techniques that are not cognitively plausible • tokenize  tag part of speech  syntax processing  semantic processing  … Distribution A

5. Constraints on Human Language Processing • Visual World Paradigm (Tanenhaus et al. 1995) • Subjects presented with a visual scene • Subjects listen to auditory linguistic input describing scene • Immediate determination of meaning • Subjects look immediately at referents of linguistic expressions, sometimes before end of expression • Incremental processing • Interactive processing (Trueswell et al. 1999) • Ambiguous expressions are processed consistent with scene “the green…” “put the arrow on the paper into the box” Distribution A

6. Cognitively Plausible Mechanism • Pseudo-deterministic, serial processing mechanism withcontext accommodation operating over a parallel, probabilistic constraint mechanism • Parallel, probabilistic constraint mechanism proposes best alternative given current context • Processor proceeds as though it were serial and deterministic, but accommodates the subsequent input as needed • Integrates the advantages of parallel processing with an essentially serial processing mechanism Distribution A

7. Pseudo-Deterministic HLP • Presents the appearance and efficiency of a serial, deterministic processor, but… • Relies on parallel, probabilistic constraint mechanism for making the best choice at each choice point • Relies on non-monotonic context accommodation mechanism to make modest adjustments to the evolving representation given the current context • Limited lookahead, delay and underspecification • Limited parallelism within serial mechanism • No backtracking Distribution A

8. Context Accommodation • If current input is unexpected given the prior context, then accommodate the input • Adjust the representation • Override • Block • Function Shift • Coerce the input into the representation • Head of nominal need not be a noun! • Head of clause need not be a verb! Distribution A

9. Context Accommodation • Related to Lewis’s notion of Limited Repair Parsing • “The putative theoretical advantage of repair parsers depends in large part on finding simple candidate repair operations” (Lewis, 1998) • “Lightweight” repair – may be no additional cost relative to processing without accommodation • Part and Parcel of normal processing – not reanalysis • Non-monotonic Distribution A

10. Types of Accommodation • Coercion • “therunningof the bull” – head of nominal • “running” construed objectively, arguments not expressed (“of the bull” functions as a modifier) • “a Bin Laden supporter” • Proper Noun functions as modifier • “the newspaper boyporchedthe newspaper” – nonce expression (H. Clark 1983) • “porched” construed as transitive action Distribution A

11. Types of Accommodation • Override • Single word vs. Multi-Word Expression (MWE) • “kicked…”  transitive verb • “kickedthe bucket”  idiomatic expression • “take…”  transitive verb • “takea hike”“takefive”“taketime”“takeplace”“takeout”“takemy wife, please”“takea long walk off a short pier” …  many idiomatic expressions • Not possible to carry all forward in parallel Distribution A

12. Types of Accommodation • Grammatical Function Shift • “he gaveitto me” • direct object (initial preference due to inanimacy) • “he gaveitthe ball” • direct object (initial preference) indirect object • “he gaveherthe ball” • indirect object (initial preference due to animacy) • “he gaveherto the groom” • indirect object (initial preference)  direct object Distribution A

13. Types of Accommodation • Grammatical Function Shift • “he saidthat…” • In context of “said”, “that” typically functions as a complementizer • But subsequent context can cause a function shift from • complementizer • “he saidthatshe was happy” • Tonominal specifierto • “he saidthatbook was funny” • Tonominal head • “he saidthat.” Distribution A

14. Types of Accommodation • Grammatical Function Shift • “pressure” vs. “pressurevalve” vs. “pressure valveadjustment” vs. “pressure valve adjustmentscrew” vs. “pressure valve adjustment screwfastener” vs. “pressure valve adjustment screw fastenerpart” vs. “pressure valve adjustment screw fastener partnumber” • Serial nouns (and verbs) incrementally shift from head to modifier function as each new head is processed • Functions like lookahead, but isn’t limited Distribution A

15. Types of Accommodation • Modulated Projection • “the rice” vs. “rice” • “the” projects a nominaland functions as a specifier • In the context of “the” “rice” projects a headwhich functions as the head of the nominal • When there is no specifier, “rice” projects a nominalas well as a nominal head Nominal Nominal + vs. spec head head head rice rice the “the rice” “rice” Distribution A

16. Types of Accommodation • Grammatical Feature Blocking and Overriding • “A few books” = indefinite + plural • A (sing, indef) few (plural) books (plural, indef) • “The books” = definite + plural • The (def) books (plural, indef) override block Distribution A

17. Types of Accommodation • Grammatical Feature Blocking and Unsetting • “He has given me the book” = active + perfect • He has (active) given (passive, perfect) me the book • “He has been given the book” = passive + perfect • He has (active) been (de-act, perfect) given (passive, perfect) the book block unset Distribution A

18. Summary of Context Accommodation • Context Accommodation is part and parcel of normal processing • Non-monotonic • Not reanalysis • Processor proceeds as though it were deterministic, but accommodates the input as needed • Gives the appearance of parallel processing in a serial, pseudo-deterministic mechanism Distribution A

19. Computational Implementation no airspeed or altitude restrictions  no negative “no” projects an object referring expression and functions as the specifier of the object referring expression Distribution A

20. Computational Implementation no airspeed or altitude restrictions  singular inanimate airspeed “airspeed” is integrated as head of the object referring expression projected by “no” – in parallel an object-head is projected to support a more complex object referring expression Distribution A

21. Computational Implementation no airspeed or altitude restrictions  function overriding The processing of “or” is delayed until the word after “or” is processed. In the context of “or” and “airspeed”, “altitude” is conjoined with “airspeed” into a conjoined object head. The conjoined object-head overrides the previous head. Distribution A

22. Computational Implementation no airspeed or altitude restrictions  plural (feature overriding) function shifting In the context of an object head, the previous head is shifted into a modifier function so that “restrictions” can function as the head Distribution A

23. Computational Implementation his… book Two referring expressions projected! distinct bind indexes his hisprojects poss-obj-spec and higher level obj-refer-expr hisis reference point for higher level obj-refer-expr Distribution A

24. Computational Implementation his book… book bookintegrated as head of higher level obj-refer-expr Distribution A

25. Computational Implementation Compare – I like his I like her her… books Only one referring expression projected! herprojects obj-refer-expr (not poss-obj-spec) her Distribution A

26. Computational Implementation her books… Second referring expression is projected! books booksintegrated as head of higher level obj-refer-expr Distribution A

27. Computational Implementation Head of higher level object referring expression is implied Number of higher level referring expression is unspecified! hers… hers is nice hers are nice implied hers Distribution A

28. Conclusions • Context accommodation, combined with parallel, probabilistic selection of alternatives, makes a serial, deterministic processor feasible • HLP is Pseudo-Deterministic • Serial, deterministic (incremental), but… • Non-monotonic (context accommodation) • Depends on highly context sensitive, parallel, probabilistic constraint mechanism (interactive) Distribution A

29. Questions?

30. Questions? Ball, J. (2007a). A Bi-Polar Theory of Nominal and Clause Structure and Function. Annual Review of Cognitive Linguistics. Ball, J. (2007b). Construction-Driven Language Processing. Proceedings of the 2nd European Cognitive Science Conference. Ball, J., Heiberg, A. & Silber, R. (2007). Toward a Large-Scale Model of Language Comprehension in ACT-R 6. Proceedings of the 8th International Conference on Cognitive Modeling. Heiberg, A., Harris, J. & Ball, J. (2007). Dynamic Visualization of ACT-R Declarative Memory Structure. Proceedings of the 8th International Conference on Cognitive Modeling. Distribution A

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32. References Henderson, J. (2004). Lookahead in Deterministic Left-Corner Parsing. Proceedings of the Workshop on Incremental Parsing: Bringing Engineering and Cognition Together. Barcelona, Spain. Huddleston, R. & Pullum G. (2005). A Student’s Introduction to English Grammar. NY: Cambridge University Press. Huddleston, R. & Pullum G.(2002). The Cambridge Grammar of the English Language. NY: Cambridge Unversity Press. Lewis, R. (1998). Reanalysis and Limited Repair Parsing: Leaping off the Garden Path. In Fodor, J. & Ferreira, F. (eds). Reanalysis in Sentence Processing. Boston: Kluwer Academic. Lewis, R. (2000). Falsifying serial and parallel parsing models: Empirical conundrums and an overlooked paradigm. Journal of Psycholinguistic Research, 29, 241-248. Marcus, M. (1980). A Theory of Syntactic Recognition for Natural Language. Cambridge, MA: The MIT Press. MacDonald, Pearlmutter & Seidenberg (1994). The lexical nature of syntactic ambiguity resolution. Psychological Review, 101, 676–703. Distribution A

33. References O’Grady, William (2005). Syntactic Carpentry, an Emergentist Approach to Syntax. Mahway, NJ:LEA. Quirk, R., Greenbaum, S., Leech, G. & Svartvik, J. (1985). A Comprehensive Grammar of the English Language. Essex, UK: Pearson Education Limited. Trueswell, J. & Tanenhaus, M. (1994). Toward a lexicalist framework for constraint-based syntactic ambiguity resolution. In C. Clifton, K. Rayner & L. Frazier (Eds.), Perspectives on sentence processing, pp. 155-180. Hillsdale, NJ: LEA. Tanenhaus, M., Spivey-Knowlton, M. Eberhard, K. & Sedivy, J. (1995). Integration of visual and linguistic information in spoken language comprehension. Science, 268, 632-634. Trueswell, J. Sekering, I., Hill, N. & Logrip, M. (1999). The kindergarten path effect: studying on-line sentence processing in young children. Cognition, 73, 89-134. Distribution A