Raluca Budiu.
The Role of Background Knowledge in Sentence Processing.
Doctoral dissertation, School of Computer Science, Carnegie Mellon
University, 2001.
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In this dissertation I describe a cognitive model of
sentence processing. The model operates at the semantic level
and can apply to verification or comprehension of metaphoric
or literal sentences, isolated or embedded in discourse. It
uses an incremental search--and--match mechanism to find a
long-term--memory referent (interpretation) for an input
sentence. The search is guided by cues such as the last few
words read or previous tentative interpretations. The process
of comprehension produces a propositional representation for
the input sentence and also keeps track of local
comprehension failures.
The model is implemented in the ACT-R framework and offers a
scalable solution to the problem of language comprehension:
its performance (in terms of speed and accuracy) is roughly
invariant to the number of facts held in the long-term
memory. Its predictions match data from psycholinguistic
studies with human subjects. Specifically, the
sentence-processing model can simulate the comprehension and
verification of metaphoric and literal sentences,
metaphor-position effects on sentence comprehension, semantic
illusions and their dependence on semantic similarity between
the distortion and the undistorted term. The products of the
sentence-processing model can explain the pattern of sentence
recall in text-memory experiments.
This dissertation also explores the modeling alternatives
faced by the design of a sentence-processing model. I show
that, to achieve comprehension speed comparable to that of
humans, a model must minimize the explicit search process and
rely on semantic associations among words. I also investigate
how the representation chosen for propositions and meanings
affects the comprehension process in a production-system
framework such as ACT-R.