Verb processing during sentence comprehension: Contextual impenetrability

This paper examines verb processing during sentence comprehension. We describe two experiments that assess the interaction between verb complexity and the structural information contained in a sentence. Verb complexity is defined in terms of a verb's possible argument structure arrangements—linguistic information arrayed against a verb's entry in the mental lexicon. Normal subjects had to perform a secondary task presented in the immediate vicinity of the verb while listening to a sentence for meaning. Reaction times to this secondary task show that all of a verb's possible argument structures are momentarily and exhaustively activated in the vicinity of the verb, even in sentences that are structurally biased toward one particular argument structure. We thus argue that verb processing in sentences involves a contextually impenetrable subcomponent of the language comprehension system.Program in Linguistics and Cognitive Science, Department of Psychology, Brandeis University.     

The case against the case against group studies

We challenge the position that only the analysis of single patients can allow us to infer normal function from impaired performance. We claim that the focus on group vs. single case studies is unprofitable and that a more useful question is how best to form abstractions of relevance to cognitive theory. In this context, we consider issues concerning the category of "agrammatism."     

Real-Time Processing Implications of Enriched Composition at the Syntax–Semantics Interface

This study reports results on the real-time consequences of aspectual coercion. We define aspectual coercion as a combinatorial semantic operation requiring computation over and above that provided by combining lexical items through expected syntactic processes. An experiment is described assessing whether or not parsing of a string requiring coercion—in addition to syntactic composition—is more computationally costly than parsing a syntactically transparent counterpart, a string that provides for an interpretable representation via syntactic composition alone. The prediction of a higher computational cost for this process is borne out by the results.     

Repetition in the transcortical aphasias

Transcortical aphasic patients were assessed on a repetition task comprised of both well-formed and deviant sentences. The patients faithfully repeated those sentences that were factually incorrect but grammatically well formed, and those sentences that were ungrammatical because of selection restriction violations. In contrast, presented with sentences featuring only minor syntactic violations (e.g., lack of number agreement), the patients spontaneously, and without awareness, resisted exact repetition; moreover, the resultant changes most often served to correct the syntactic deviations. Repetitions of sentences of this latter type also revealed a difference between the patients as a function of level of comprehension. The transcortical motor aphasic patient was influenced by semantic factors in his alterations of the minor syntactic violations, while the transcortical sensory aphasic was not. These findings are discussed in relation to the notion of autonomous syntactic processing. They are taken to suggest that syntactic facts such as number agreement are represented at a level in the processing chain that is distinct from that of semantic representation.     

The appreciation of antonymic contrasts in aphasia

To secure information on the ability of aphasic patients to comprehend antonymic relations, the kinds of confusions typically made, and the extent to which antonymic sensitivity depends upon mode of presentation and task demands, three linguistic and nonlinguistic tests were administered to aphasic patients, right hemisphere-damaged patients, and non-neurological controls. Although difficulty with antonymous relations was found among all the organic patients, the kinds of problems evidenced and the relative profile of difficulties differed across populations. Among the principal findings were the generally preserved sensitivity to antonymy found among anterior (particularly Broca's) aphasics; a surprising insensitivity to antonymy and a preference for synonyms, found among right hemisphere patients, particularly on the nonlinguistic tasks; a relative preservation of sensitivity to antonymy on nonlinguistic tasks, coupled with a loss of such sensitivity on linguistic tasks, found among posterior (particularly Wernicke's) aphasics; a proclivity toward stereotypical correct responses among the organic patients; and an absolutely worse performance by right hemisphere patients on tasks involving antonymic relations in pictures and abstract designs.     

The time course of automatic lexical access and aging

This study addresses the issue of cognitive slowing in the elderly by examining the time course of automatic lexical access. College-aged subjects typically show a brief rise time (300-500 msec) for lexical access. In the present study, we examine whether there are changes in rapid, automatized access routines with age. Elderly and college-aged subjects performed a lexical decision task wherein semantically related words embedded in a continuous list were presented one at a time with a varying (300-1500 msec) inter-word interval. The use of a continuous list, a repeated word, and a very short inter-stimulus interval allowed automatic lexical access to be straightforwardly examined. The elderly subjects showed an onset of automatic lexical access that was similar in time frame to that for college-age subjects. These findings suggest that wherever the locus of age-related slowing may be, it is not in the early, language-specific processing devices that mediate lexical access.     

Semantic operations in aphasic comprehension: implications for the cortical organization of language.

We provide data on the neurological basis of two semantic operations at the sentence level: aspectual coercion and complement coercion. These operations are characterized by being purely semantic in nature; that is, they lack morphosyntactic reflections. Yet, the operations are mandatory (i.e., they are indispensable for the semantic well formedness of a sentence). Results indicate that, whereas Broca's patients have little or no trouble understanding sentences requiring these operations (performance was above chance for all conditions), Wernicke's patients performed at normal-like levels only for sentences that did not require these operations. These findings suggest that sentence-level semantic operations rely very specifically on the integrity of the cortical area associated with Wernicke's aphasia, but not on the region corresponding to Broca's aphasia. In the context of other findings from lesion and imaging studies, this evidence allows a view of the cortical distribution of language capacity that is drawn along a linguistic line, one which distinguishes syntactic from semantic operations.     

Modularity in locating Wh-gaps

In this paper we report our finding that the parsing routine responsible for locating the deep-structure position of a wh-phrase operates independently of semantic/pragmatic knowledge, suggesting a modular organization of the human sentence processor. Specifically, wh-phrases that were semantically implausible as a direct object of the matrix verb were nonetheless reactivated in that position. Further, reactivation of the wh-phrase was observed despite the fact that the matrix verbs were three-place predicates (e.g.,remind) — a class of verbs which, some experiments suggest, allow interactive effects (e.g., Tanenhaus, Boland, Garnsey, & Carlson, 1989). We argue that this disparity in findings is due to the difference between the cross-modal lexical priming (CMLP) task used in the present study, and the tasks used by Tanenhaus et al.We gratefully acknowledge Penny Prather, Catherine Stern, and David Swinney for their technical assistance, and also Brian Hickok. This work has also benefitted from helpful discussions with Michael Tanenhaus and Stephen Crain, as well as from the comments of two anonymous reviewers.     

Processing complexity and sentence memory: evidence from amnesia.

This study examines sentence memory as a function of linguistic processing complexity in amnesic patients. Sentence length as well as lexical and syntactic complexity were manipulated in two sentence repetition experiments. It was found that the amnesic patients performed considerably worse than the control subjects and that performance decreased: (1) when sentence length was increased by the addition of adjuncts compared to arguments of the verb; (2) when the verb selected more thematic frames; and (3) when sentences involved "empty" argument positions that must be linked to antecedents, particularly across clausal boundaries. These data showed how linguistic complexity affects sentence memory and implied that the amnesic deficit did not involve a generalized difficulty for materials of similar length, rather, the deficit was specific to certain representational types and processing routines.