A Labelled Analytic Theorem Proving Environment for Categorial Grammar

We present a system for the investigation of computational properties of categorial grammar parsing based on a labelled analytic tableaux theorem prover. This proof method allows us to take a modular approach, in which the basic grammar can be kept constant, while a range of categorial calculi can be captured by assigning different properties to the labelling algebra. The theorem proving strategy is particularly well suited to the treatment of categorial grammar, because it allows us to distribute the computational cost between the algorithm which deals with the grammatical types and the algebraic checker which constrains the derivation.Comment: 11 pages, LaTeX2e, uses examples.sty and a4wide.st

Syntactic and semantic mismatches in English number agreement

In English, it is possible for a morphologically singular collective noun like government to control both singular (syntactic) agreement and plural (semantic) agreement in the same sentence (e.g. The government has praised themselves). It has been claimed that sentences with the opposite pattern of agreeing elements are ungrammatical (e.g. *The government have praised itself), and there is a corresponding asymmetry in corpus frequencies of these two configurations. Across two acceptability judgement experiments, we show that the acceptability contrast is affected by the relative order of the two agreeing elements, with degraded acceptability in the case where the first agreeing element shows plural agreement and the second shows singular agreement, relative to the opposite configuration. This pattern is found both when the agreeing verb precedes the reflexive, and when the reflexive precedes the verb. Overall, the results suggest that the initial formation of a semantic agreement dependency between an agreement target and a collective controller makes subsequent morpho-syntactic agreement with the same controller less accessible. We argue that any theoretical account of these results would require an important role for incremental processing. &nbsp

Retrieval interference and semantic interpretation

Similarity-based interference has played an important role in motivating cue-based models of memory retrieval during language comprehension. One example of interference comes from illusions of grammaticality, where ungrammatical sentences are perceived as grammatical (e.g. ‘the key to the cabinets were rusty’). While such effects indicate interference influences perception of sentence grammaticality, less is known about how interference influences the semantic interpretation assigned to a sentence. We report two reading experiments that manipulated sentence plausibility, rather than grammaticality, as a diagnostic of interference. In both experiments, although reading times were longer for implausible sentences, this plausibility effect was reliably attenuated when a distractor item partially matched the cues at retrieval. We interpret these results as being compatible with the predictions of cue-based parsing. The illusions of plausibility that we report indicate that similarity-based retrieval interference has a potent influence on the semantic interpretation that is assigned to a sentence during processing

The real-time status of strong and weak islands

In two eye-tracking reading experiments, we used a variant of the filled gap technique to investigate how strong and weak islands are processed on a moment-to-moment basis during comprehension. Experiment 1 provided a conceptual replication of previous studies showing that real time processing is sensitive to strong islands. In the absence of an island, readers experienced processing difficulty when a pronoun appeared in a position of a predicted gap, but this difficulty was absent when the pronoun appeared inside a strong island. Experiment 2 showed an analogous effect for weak islands: a processing cost was seen for a pronoun in the position of a predicted gap in a that-complement clause, but this cost was absent in a matched whether clause, which constitutes a weak island configuration. Overall, our results are compatible with the claim that active dependency formation is suspended, or reduced, in both weak and strong island structures

Illusions of plausibility in adjuncts and co-ordination

Illusions of grammaticality, where ungrammatical sentences are misperceived as grammatical (e.g. The key to the cabinets were rusty), have been widely studied during language comprehension. Such grammatical illusions have been influential in debate surrounding so-called representational and retrieval-based accounts of linguistic dependency resolution. Whether analogous illusions of plausibility occur at the level of semantic interpretation has only recently begun to be examined, and thus far, these illusions have been restricted to a narrow range of linguistic phenomena. In two eye-tracking during reading experiments (n = 48 in each) and two self-paced reading experiments (n = 192 in each) we examined the possibility of semantic illusions during the processing of adjuncts and co-ordination. Across experiments, our results suggest illusions of plausibility during dependency resolution, though interference effects were clearer in adjuncts than co-ordination. We argue that our findings are more compatible with retrieval-based rather than representational accounts of linguistic dependency resolution