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Biomedical subjects

D Swinney

Publications and source records attributed to D Swinney.

18 recordsLinked to original sources
PubMed1998

Gap-filling and end-of-sentence effects in real-time language processing: implications for modeling sentence comprehension in aphasia.

We present an on-line study showing different sources of lexical activation during sentence comprehension, distinguishing in this respect between reflexive syntactic and less temporarily constrained nonsyntactic sources. Specifically, we show that both the syntactic process of gap filling and a nonsyntactic end-of-sentence effect can be measurable in real time and can be temporally separated. The distinction between activation sources provides a new perspective on real-time sentence comprehension in aphasia and accounts for the disparate results reported in the literature.

Aged↗
PubMed1996

Coreference processing and levels of analysis in object-relative constructions; demonstration of antecedent reactivation with the cross-modal priming paradigm.

This paper is concerned with two related issues in sentence processing--one methodological and one theoretical. Methodologically, it provides an unconfounded test of the ability of the cross-modal lexical priming task, when used appropriately, to provide detailed evidence about the time-course of antecedent reactivation during sentence processing. Theoretically, it provides a study of the nature of the representation that is examined when a reference-seeking element is linked to its antecedent during the processing of object-relative clause constructions. In these studies, subjects heard sentences which contained a lexical ambiguity placed in a strong biasing context. In one study this ambiguous word was the "moved" or "fronted" object of the verb in an object-relative construction. A cross-modal lexical priming (CMLP) naming task was used to determine whether one or more of the meanings of the ambiguity are activated at three temporally distinct points during the sentence: (1) immediately after the lexical ambiguity (Study 1); (2) a later point that was 700 milliseconds before the offset of the main verb (Study 2); (3) immediately after this main verb (at the gap in this filler-gap construction) (Study 2). The probes in the CMLP task were controlled for potential confounds. The results demonstrate the following: At Test Point 1, all meanings of the ambiguity were activated; at Test Point 2, neither meaning of the ambiguity was (still) activated; at Test Point 3, only a single (context-relevant) meaning of the ambiguity was reactivated. It is concluded that an underlying (deep; non-surface-level) memorial representation of the sentence is examined during the process of linking an antecedent to a structural position requiring a referent, and that the CMLP task provides an unbiased measure of this reactivation. Further, it is concluded that this effect cannot be accounted for under a "compound cue" (Ratcliff & McKoon, 1994) explanation.

Humans↗
PubMed1995

Syntactic processing in aphasia.

In this report we comment upon subject selection and methodology, and we describe some recent studies of syntactic processing in aphasia. Our data show that, like neurologically intact subjects, Wernicke's patients reactivate moved constituents (instantiate coreference) at the site of their extraction (even for sentences that they do not understand). Broca's patients, by constrast, are shown not to create such syntactically governed links (even for sentences that they do understand). These data isolate the processing bottleneck in Broca's aphasia and more generally suggest that syntactic comprehension limitations can be traced to changes in cortically localizable resources that sustain lexical processing.

Aphasia, Broca↗
PubMed1995

Participant roles and the processing of verbs during sentence comprehension.

This paper explores the nature of thematic information made available when a verb is accessed during sentence comprehension. Following Shapiro, Zurif, and Grimshaw (1987), a cross-modal lexical decision (interference) task was employed to examine whether either the number of argument structures or the number of participant (thematic) roles inherent in a verb cause an increase in processing load upon access of the verb. It was determined that there was no evidence for such an increased processing load covarying with the number of argument structures of the verb, at least for those verb types examined in this study. However, there was an increase in processing load as a direct function of the number of participant roles carried by the verb. It is concluded that the participant roles (thematic roles associated with the central meaning of the verb) are stored with the representation of a verb and are made immediately available upon access of the verb for further processing during comprehension.

Female↗
PubMed1994

Functional localization in the brain with respect to syntactic processing.

This report describes some recent examinations of the ability of aphasic patients to construct syntactically governed dependency relations in real time. The data show that Wernicke's patients can link the elements of dependency relations in the same way as neurologically intact subjects, even for sentences that they do not understand. Broca's patients, by contrast, are shown to be unable to create such links, even for sentences that they do understand. These data underline the isolability of this stage of syntactic analysis and they suggest that comprehension limitations statable in syntactic terms can be traced to changes in cortically localizable processing resources.

Aphasia, Broca↗
PubMed1994

Using cross-modal lexical decision tasks to investigate sentence processing.

Recent investigations of sentence processing have used the cross-modal lexical decision task to show that the antecedent of a phonologically empty noun phrase (specifically, WH-trace) is reactivated at the trace position. G. McKoon, R. Ratcliff, and G. Ward (1994) claimed that (a) a design feature concerning the choice of related and unrelated targets is a possible confound in this work and (b) the conclusions drawn from this previous research are therefore called into question. These claims are considered in light of both McKoon et al.'s experimental findings and results of our own experiments in which we test their linguistic materials. We argue that their results may be due to the nature of their materials. Additionally, we argue that a follow-up experiment reported by G. McKoon and R. Ratcliff (1994) used a technique that is not comparable to the cross-modal lexical decision task. It is concluded that current evidence supports the claim that structural information is using during on-line sentence processing and that the cross-modal technique is sensitive to this.

Cognition↗
PubMed1993

An on-line analysis of syntactic processing in Broca's and Wernicke's aphasia.

This paper is about syntactic processing in aphasia. Specifically, we present data concerning the ability of Broca's and Wernicke's aphasic patients to link moved constituents and empty elements in real time. We show that Wernicke's aphasic patients carry out this syntactic analysis in a normal fashion, but that Broca's aphasic patients do not. We discuss these data in the context of some current grammar-based theories of comprehension limitations in aphasia and in terms of the different functional commitments of the brain regions implicated in Broca's and Wernicke's aphasia, respectively.

Acoustic Stimulation↗
PubMed1991

Real-time examinations of lexical processing in aphasics.

We argue that the lesion localizing value of disruptions to modular information processing systems emerges most clearly from on-line analyses of processing. In this respect we seek to show that left anterior (but not left posterior) damage causes slowed information access and we discuss the manner in which this slowing might yield some of the specific syntactic limitations charted in Broca's aphasia. The general possibility we raise is that the cortical area implicated in Broca's aphasia is not necessarily the locus of syntactic representations, but rather sustains particular time-based operating characteristics that in turn sustain normal real-time parsing.

Aphasia, Broca↗
PubMed1991

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.

Adult↗
PubMed1991

An evaluation of assumptions underlying the single-patient-only position in neuropsychological research: a reply.

This note challenges the position adopted by A. Caramazza and W. Badecker (1989, Brain and Cognition 10, 256-295) that, since the a priori classification of patients can only be theoretically arbitrary, the basic unit of analysis in cognitive neuropsychology must be the individual patient. We argue that even if there is no prior theory to justify patient classification, this does not preclude group studies; syndromes are what the world gives us--they constrain theory, permitting groups to be formed for research purposes. We also reexamine a particular example of group-based research that was extensively criticized by Caramazza and Badecker. We confront each of their criticisms, and, again, demonstrate the validity of group-based research.

Aphasia, Broca↗
PubMed1990

Effects of food snacks on cognitive performance in male college students.

The effects of food snacks consumed in the late afternoon on cognitive performance in college-aged men were investigated in two experiments. The effects of the snacks were tested in the same subjects after they either consumed or skipped lunch. In the first experiment, the calorie-rich snack was a confectionery product, while in the second experiment, the snack was fruit-flavored yogurt. In both experiments, performance on cognitive tasks following consumption of the calorie-rich snack was compared to performance following consumption of a very low calorie snack (lemon-lime flavored diet soda without caffeine). Four cognitive tasks were employed: digit span recall (forward and backward), arithmetic reasoning, reading, and attention. In both experiments, subjects recalled significantly more digits in the backward digit span test and responded significantly faster in the attention task when they had consumed the calorific snack than when they had consumed the diet soft drink. Additionally, in Experiment 2, subjects solved significantly more arithmetic problems and solved these problems in significantly less time after eating a fruit-flavored yogurt than after consuming the diet soft drink. Results of these experiments suggest that a late afternoon energy-containing snack can have positive effects on cognitive performance on tasks that require sustained attention.

Adult↗
PubMed1989

The role of structure in coreference assignment during sentence comprehension.

This paper examines the role of syntactic constraints on the reactivation and assignment of antecedents to explicit and implicit anaphoric elements during sentence comprehension. Evidence from on-line studies examining the time course of coreference processing supports the view that reactivation of potential antecedents is restricted by grammatical constraints when they are available. When structural information cannot serve to constrain antecedent selection, then pragmatic information may play a role, but only at a later point in processing.

Cognition↗
PubMed1979

On the relationship of hemispheric specialization and developmental dyslexia.

Hemispheric specialization for linguistic material was compared for normal and dyslexic subjects under dichotic listening (Experiment 1) and hemi-retinal presentation (Experiment 2) conditions. In both experiments, group data indicated that dyslexic subjects were, overall, less accurate in their performance than normals but that both groups showed similar right ear/visual field superiority. However, examination of individual subjects scores in both experiments indicated that the distribution of lateralization scores for dyslexic subjects was bimodal, whereas that for normal subjects was unimodal. These results suggest that the dyslexic 'population' is heterogeneous with regard to cerebral lateralization and that previous work treating it as homogeneous is most likely misleading. It appears important to both carefully examine individual subject data in such studies and to consider the consequences of there being different types of cerebral lateralization etiologies for what has been typically considered to be a homogeneous dyslexic population.

Child↗