Context Accommodation in Human Language Processing June 2010 Jerry T. Ball Senior Research Psychologist 711 th 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 Foundations Language 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-R cognitive architecture and modeling environment 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 with context 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 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! Context Accommodation 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 Coercion – “the running of 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 boy porched the newspaper” – nonce expression (H. Clark 1983) “porched” construed as transitive action Types of Accommodation Distribution A

11 Override – Single word vs. Multi-Word Expression (MWE) “kicked…”  transitive verb – “kicked the bucket”  idiomatic expression “take…”  transitive verb – “take a hike” “take five” “take time” “take place” “take out” “take my wife, please” “take a long walk off a short pier” …  many idiomatic expressions Not possible to carry all forward in parallel Types of Accommodation Distribution A

12 Grammatical Function Shift – “he gave it to me” direct object (initial preference due to inanimacy) – “he gave it the ball” direct object (initial preference)  indirect object – “he gave her the ball” indirect object (initial preference due to animacy) – “he gave her to the groom” indirect object (initial preference)  direct object Types of Accommodation Distribution A

13 Grammatical Function Shift – “he said that…” In context of “said”, “that” typically functions as a complementizer – But subsequent context can cause a function shift from complementizer – “he said that she was happy” To nominal specifier to – “he said that book was funny” To nominal head – “he said that.” Types of Accommodation Distribution A

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

15 Modulated Projection – “the rice” vs. “rice” – “the” projects a nominal and functions as a specifier – In the context of “the” “rice” projects a head which functions as the head of the nominal – When there is no specifier, “rice” projects a nominal as well as a nominal head Types of Accommodation Nominal spec the head rice + vs. head rice Nominal “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 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 Summary of Context Accommodation Distribution A

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

20 Computational Implementation “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 singularinanimate no airspeed or altitude restrictions  Distribution A airspeed

21 Computational Implementation 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. function overriding no airspeed or altitude restrictions  Distribution A

22 Computational Implementation 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 plural (feature overriding) no airspeed or altitude restrictions  Distribution A

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

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

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

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

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

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

31 Crocker, M. (1999). Mechanisms for Sentence Processing. Garrod & Pickering (eds.), Language Processing, London: Psychology Press. References Christianson et al. (2001). Thematic roles assigned along the garden path linger. Cognitive Psychology, 42, Bever, T. (1970). The cognitive basis for linguistic structures. In J.R. Hayes (ed.), Cognition and Language Development, New York: Wiley. Gibson, E. & Pearlmutter, N. (2000). Distinguishing Serial and Parallel Parsing. Journal of Psycholinguistic Research, 29, Clark, H. (1983). Making sense of nonce sense. In G. Flores d’Arcais & R. Jarvella (Eds.), The Process of Language Understanding, New York: John Wiley. Culicover, P. & Jackendoff, R. (2005). Simpler Syntax. Oxford: Oxford University Press. Gibson, E. (1991). A computational theory of human linguistic processing: Memory limitations and processing breakdown. Unpublished doctoral dissertation, Carnegie Mellon University, Pittsburgh, PA. Biber, D., Conrad, S. & Leech, G. (2002). Student Grammar of Spoken and Written English. Essex, UK: Pearson Education Limited. Distribution A

32 References 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, 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. Huddleston, R. & Pullum G. (2002). The Cambridge Grammar of the English Language. NY: Cambridge Unversity Press. Huddleston, R. & Pullum G. (2005). A Student’s Introduction to English Grammar. NY: Cambridge University Press. Henderson, J. (2004). Lookahead in Deterministic Left-Corner Parsing. Proceedings of the Workshop on Incremental Parsing: Bringing Engineering and Cognition Together. Barcelona, Spain. Distribution A

33 References Tanenhaus, M., Spivey-Knowlton, M. Eberhard, K. & Sedivy, J. (1995). Integration of visual and linguistic information in spoken language comprehension. Science, 268, Trueswell, J. Sekering, I., Hill, N. & Logrip, M. (1999). The kindergarten path effect: studying on-line sentence processing in young children. Cognition, 73, O’Grady, William (2005). Syntactic Carpentry, an Emergentist Approach to Syntax. Mahway, NJ: LEA. 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 Hillsdale, NJ: LEA. Quirk, R., Greenbaum, S., Leech, G. & Svartvik, J. (1985). A Comprehensive Grammar of the English Language. Essex, UK: Pearson Education Limited. Distribution A