This paper proposes a new theory of the relationship between the sentence processing mechanism and the available computational resources. This theory -- the Syntactic Prediction Locality Theory (SPLT) -- has two components: an integration cost component and a component for the memory cost associated with keeping track of obligatory syntactic requirements. Memory cost is

It is widely appreciated (e.g. Marr, 1982) that the difficulty of a particular computation varies according to how the input data are presented. What is less well understood is the effect of this computation/representation trade-off within familiar learning paradigms. We argue that existing learning algorithms are often poorly equipped to solve problems involving a certain type of important and widespread statistical regularity, which we call `type-2 regularity'. The solution in these cases is to trade achieved representation against computational search. We investigate several ways in which such a trade-off may be pursued including simple incremental learning, modular connectionism, and the developmental hypothesis of `representational redescription'. In addition, the most distinctive features of human cognition --- language and culture --- may themselves be viewed as adaptations enabling this representation/computation trade-off to be pursued on an even grander scale.

We present a detailed process theory of the moment-by-moment working-memory retrievals and associated control structure that subserve sentence comprehension. The theory is derived from the application of independently motivated principles of memory and cognitive skill to the specialized task of sentence parsing. The resulting theory construes sentence processing as a series of skilled associative memory retrievals modulated by similarity-based interference and fluctuating activation. The cognitive principles are formalized in computational form in the Adaptive Control of Thought–Rational (ACT–R) architecture, and our process model is realized in ACT–R. We present the results of 6 sets of simulations: 5 simulation sets provide quantitative accounts of the effects of length and structural interference on both unambiguous and garden-path structures. A final simulation set provides a graded taxonomy of double center embeddings ranging from relatively easy to extremely difficult. The explanation of center-embedding difficulty is a novel one that derives from the model’s complete reliance on discriminating retrieval cues in the absence of an explicit representation of serial order information. All fits were obtained with only 1 free scaling parameter fixed across the simulations; all other parameters were ACT–R defaults. The modeling results support the hypothesis that fluctuating activation and similarity-based interference are the key factors shaping working memory in sentence processing. We contrast the theory and empirical predictions with several related accounts of sentence-processing complexity.

Results from an English acceptability-rating experiment are presented which demonstrate that people �nd doubly nested relative clause structures just as acceptable when only two verb phrases are included instead of the grammatically required three. Furthermore, the experiment shows that such sentences are acceptable only when the intermediate verb phrase is omitted. A number of speci�c accounts of forgetting are considered. Two early proposed theories of this effect, the disappearing syntactic nodes hypothesis (Frazier, 1985) and the least recent nodes hypothesis (Gibson, 1991), are not consistent with the experimental results. The results, together with other acceptability patterns, suggest that the representations that are retained (and subsequently forgotten) in processing sentences consist of the lexical wordstrings processed thus far. Three possible accounts of the results are considered: (1) the high memory cost pruning hypothesis within the framework of Gibson (1998); (2) a recency/primacy account; and (3) a connectionist account (Christiansen & Chater, in press).

ing away from irrelevant details is a theoretical virtue, but the kinds of abstractions that module geography makes can lead to incorrect inferences from data. That such a possibility exists is clearly demonstrated by the working memory research of Just & Carpenter (1992). Briefly, Just and Carpenter have argued that some garden path effects that were previously interpreted in terms of a syntactically encapsulated module can instead be explained by individual differences in working memory capacity. Such an explanation is not considered in a theoretical framework that systematically ignores the role of memory structures in parsing. This point should be taken regardless of whether one is convinced by the current body of empirical support for this particular model---the fact remains that such an explanation could in principle account for the data, and these alternative explanations are only discovered by developing functionally complete architectures. The next few sections describes what ...

This paper presents three self-paced, word-by-word reading experiments that test for the existence of on-line syntactic storage costs in English. To investigate this issue, we compared reading times for sentence regions in which storage costs varied, keeping other factors constant. Experiment 1 manipulated the number of verbs needed to form a grammatical sentence. Experiment 2 investigated whether filler-gap dependencies incur storage costs, and Experiment 3 investigated whether prepositional phrase arguments of verbs incur storage costs. The results of all three experiments demonstrate the role of online storage costs in sentence comprehension. Taken together with other results in the literature, the results also support a theory of sentence comprehension which includes empty categories mediating filler-gap dependencies. 2

What precisely is the universal nature of the human syntactic parser, such that it copes easily with some embedded structures, yet fails so dramatically on others (e.g., classic double center-embeddings)? A theory is proposed in the form of an architecture for parsing based on two simple ideas. The first is that human short-term memory is an indexing structure which can give rise to interference effects (storage limitations) when contents overlap with respect to the indices. For parsing, the contents are syntactic structures, and the indices are potential structural relations. The second idea is that the capacity of STM is the minimum capacity required to support the basic functions of parsing. The theory successfully accounts for the contrasts between over 50 difficult and acceptable constructions from English, French, German, Hebrew, Japanese, Mandarin, and Spanish. The theory has independent psychological and computational motivation, and is a functional part of a broader cognitive ...

There is a certain tension between the role which acceptability judgements play in linguistics and the level of their scientific underpinning. Judgements of grammaticality form the

A series of arguments is presented showing that words are not stored in memory in a way that resembles the abstract, phonological code used by alphabetical orthographies or by linguistic analysis. Words are stored in a very concrete, detailed auditory code that includes nonlinguistic information including speaker’s voice properties and other details. Thus, memory for language resembles an exemplar memory and abstract descriptions (using letter-like units and speaker-invariant features) are probably computed on the fly whenever needed. One consequence of this hypothesis is that the study of phonology should be the study of generalizations across the speech of a community and that such a description will employ units (segments, syllable types, prosodic patterns, etc.) that are not necessarily employed as units in speakers’ memory for language. That is, the psychological units of language are not useful for description of linguistic generalizations and linguistic generalizations across a community are not useful for storing the language for speaker use.

computation. This paper argues that such a characterization is correct, and that fundamental properties of grammar can and should be understood in terms of restrictions on the complexity of possible grammatical computation, when defined in terms of generative capacity. More specifically, the paper demonstrates that the computational restrictiveness imposed by Tree Adjoining Grammar provides important insights into the nature of human grammatical knowledge. 2 1