Computational Linguistics Colloquium

Thursday, 12 February, 16:15
Conference Room, Building C7 4

Prediction and retrieval in dependency resolution: Models and data

Resolving a head-dependent relationship a central act in online sentence comprehension; without it, comprehension is impossible. Fillers must be connected to gaps, antecedents to pronouns and reflexives, licensors to polarity items, incoming phrases with one of multiple possible attachment sites; and so on. Although such dependency resolution processes often proceed smoothly, at other times difficulty occurs: targeted items are retrieved slowly or not retrieved at all, or the wrong item is retrieved. What causes such breakdowns? Understanding the nature of online dependency resolution remains a central open problem in sentence processing research.

Prediction and retrieval based difficulty have been invoked to explain dependency resolution difficulty. Retrieval theory has argued primarily for decay and/or interference as explanatory primitives (Gibson 2000, Lewis and Vasishth 2005, Van Dyke and McElree 2007, among others), while predictive or expectation-based accounts rely on quantifying the uncertainty about the upcoming word in a sentence (some recent examples are: Hale 2001, Levy 2008, Boston, Hale, Patil, Kliegl, Vasishth 2008, Demberg and Keller 2008).

Retrieval theory and expectation-based explanations are, theoretically, orthogonal aspects of the incremental parsing process. This raises the possibility that both classes of explanation should operate more or less simultaneously to determine parse difficulty. In order to test this hypothesis, I present a scalable computational model of online parsing that delivers retrieval and prediction cost in a unified framework for arbitrary sentences (Boston et al 2009; cf. Patil et al 2009). I show how retrieval and prediction based accounts can be combined to explain a range of benchmark data gathered in my laboratory using methodologies such as self-paced reading, eyetracking and event related potentials.

Relevant references:

Boston, M.F., Hale, J.T., Kliegl, R., Patil, U., and Vasishth, S. (2008) Parsing costs as predictors of reading difficulty: An evaluation using the Potsdam Sentence Corpus. in press, Journal of Eye Movement Research, 2008.

Boston, M.F., Hale, J.T., Kliegl, R., and Vasishth, S. (2008) Surprising parser actions and reading difficulty. In Proceedings of the ACL-HLT Conference, Columbus, OH, 2008. The Ohio State University.

Boston, M.F., Hale, J.T., Vasishth, S. and Kliegl, R. (2009) Examining syntactic factors in eye fixation durations. Poster to be presented at CUNY, UC Davis.

Patil, U., Boston, M.F., Hale, J.T., Vasishth, S. and Kliegl, R. (2009) The interaction of surprisal and working memory cost during reading. Poster to be presented at CUNY, UC Davis.

Crocker, M. W., & Brants, T. (2000). Wide-coverage probabilistic sentence processing. Journal of Psycholinguistic Research, 29(6), 647-669.

Demberg, V., & Keller, F. (2008). Data from eye-tracking corpora as evidence for theories of syntactic processing complexity. Cognition.

Gibson, E. (2000). Dependency locality theory: A distance-based theory of linguistic complexity. In A. Marantz, Y. Miyashita, & W. O`Neil (Eds.), Image, language, brain: Papers from the first mind articulation project symposium. Cambridge, MA: MIT Press.

Hale, J. (2001). A probabilistic Earley parser as a psycholinguistic model. In Proceedings of the Second Meeting of the North American Chapter of the Association for Computational Linguistics (pp. 1-8). Pittsburgh, PA: Carnegie Mellon University.

Levy, R. (2008). Expectation-based syntactic comprehension. Cognition.

Lewis, R. L., & Vasishth, S. (2005, May). An activation-based model of sentence processing as skilled memory retrieval. Cognitive Science, 29, 1-45.

Lewis, R. L., Vasishth, S., & Van Dyke, J. (2006). Computational principles of working memory in sentence comprehension. Trends in Cognitive Sciences, 10(10), 447-454.

Vasishth, S., Bruessow, S., Lewis, R. L., & Drenhaus, H. (2008). Processing polarity: How the ungrammatical intrudes on the grammatical. Cognitive Science, 32(4).

Van Dyke, J., & McElree, B. (2006). Retrieval interference in sentence comprehension. Journal of Memory and Language, 55, 157-166.

Vasishth, S., & Lewis, R. L. (2006). Argument-head distance and processing complexity: Explaining both locality and antilocality effects. Language, 82(4), 767-794.

If you would like to meet with the speaker, please contact Berry Claus.