Charting the time-course of language processing.
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Brain↗
Biomedical subjects
L P Shapiro
Publications and source records attributed to L P Shapiro.
The temporal unfolding of local acoustic information and sentence context.
The purpose of this study was to investigate the temporal unfolding of local acoustic information and sentence context using both cross-modal interference (CMI) and word-monitoring tasks. The timing of sentence context effects have important theoretical implications for models of language processing (e.g., initial context independence vs. initial interaction). Yet, different tasks tend to yield different results. For both experiments, stimuli from an acoustically manipulated "goat-to-coat" continuum were embedded in sentences whose interpretation was biased toward either "goat" or "coat." In experiment 1 (CMI), the primary task was listening to sentences for comprehension; the interference task was a word/nonword decision to an unrelated visual probe that appeared at one of three positions within the sentence. Results showed immediate effects of the acoustic manipulation, but only delayed effects of sentence context. These results were interpreted to indicate that phonological processing is initially context-independent but is followed by rapid context integration. Experiment 2 used a word-monitoring task: Response times were significantly longer when sentence context was incongruent with the monitoring target, showing an immediate effect of context. The apparently contradictory results of the two experiments together support an account of language processing in which phoneme categorization is initially independent of sentence context unless an explicit judgment about the identity of the target is required.
Adult↗
Categorization of ambiguous sentences as a function of a changing prosodic parameter: a dynamical approach.
The present study investigates the dynamics of changes in interpretation of ambiguous sentences. The sentences used had alternative interpretations with different surface structures (bracketing). Continua were created by systematic manipulation of prosodic cues (relative foot duration), resulting in stimulus sentences that spanned the range between the two interpretations. Continua were presented to subjects who were requested to indicate as quickly as possible which meaning they perceived. The pattern of responses and response times revealed the presence of hysteresis. That is, when the values of prosodic parameters are congruent with both interpretations, the individual's recent history decides which meaning will be perceived. Thus, we can treat this categorization process as a transition from an initially stable meaning that loses stability with variations in prosody (our control parameter). The same underlying dynamics have been observed in studies of perception of syllables and aspects of visual perception. Apart from demonstrating the same characteristics of pattern formation at various levels of cognition, the study points to the usefulness of the dynamical approach in the investigation of language understanding.
Cognition↗
The role of syntactic complexity in training wh-movement structures in agrammatic aphasia: optimal order for promoting generalization.
This study examined the postulate that training production of syntactically complex sentences results in generalization to less complex sentences that have processes in common with treated structures. Three agrammatic aphasic patients were trained to produce wh-movement structures, object clefts and/or object extracted who-questions, while generalization between these structures was tested. One NP-movement structure, passive sentences, also was tested for control purposes. Wh-movement occurs from the direct object position to specifier position in the complementizer phrase [SPEC, CP] for both wh-movement structures. In who-questions movement occurs in the matrix sentence, whereas, in object clefts movement occurs within an embedded relative clause, rendering them the most complex. Results showed robust generalization effects from object clefts to matrix who-question for 1 participant (D.L.); however, no generalization was noted from who-questions to object clefts for another (F.P.), and 1 participant (C.H.) showed acquisition of who-questions, but not object clefts, during the baseline condition without direct treatment. As expected, none of the participants showed improved production of passives. These findings supported those derived from our previous studies, indicating that generalization is enhanced not only when target structures are related along dimensions articulated by linguistic theory, but also when the direction of treatment is from more to less complex structures. The present findings also support proposals that projections of higher levels in the syntactic treatment are dependent on successful projection of lower levels. For our participants, training movement within CP in a lower (embedded) clause resulted in their ability to project to CP at higher levels.
Adult↗
"How to milk a coat:" the effects of semantic and acoustic information on phoneme categorization.
This study examined the effect of sentence context and local acoustic structure on phoneme categorization. Target stimuli from a 10-step GOAT-COAT continuum, differing only on a temporal cue for voice onset time (VOT), were embedded in carrier sentences that biased interpretation toward either "goat" or "coat." While subjects listened to the sentences they also responded as quickly as possible to a visual probe by indicating whether the probe matched the target stimulus they heard. Results showed that the interaction of VOT and sentence context significantly affected both identification and RT for stimuli near the perceptual boundary; the identification function showed a boundary shift in favor of the biased context and peak response times for each context reflected the shifted identification boundaries. In addition, response times were faster for identification of stimuli near the category boundary when responses were congruent, rather than incongruent with the sentence context. The response time differences for congruent versus incongruent responses in the boundary region are interpreted as depending on the results of initial phonological analysis; potentially ambiguous categorizations may be subject to additional evaluation in which a context-congruent response is both preferred and available earlier.
Humans↗
Training and generalized production of wh- and NP-movement structures in agrammatic aphasia.
The present research examines production of "complex" sentences, which involve movement of noun phrases (NPs), in 2 agrammatic aphasic subjects. According to linguistic theory (Chomsky, 1991, 1993), such sentences are derived using one of two movement operations, either wh- or NP-movement, subsumed under the general rule "move alpha." In this experiment recovery of both wh- and NP-movement derived sentences was investigated using a treatment research paradigm. Subjects were sequentially trained to produce either wh-movement (i.e., who questions, object clefts) or NP-movement (i.e., passives, subject-raising structures) derived sentences. Throughout training, generalization to untrained sentences relying on both types of movement was tested. The influence of training on aspects of narrative discourse also was examined. Results showed generalization patterns constrained to type of movement. Training wh-movement structures resulted in generalized production of untrained wh-movement structures without influencing production of NP-movement structures. Similarly, training of NP-movement structures resulted in generalization only to other sentence types also relying on NP-movement. Aspects of sentence production in narrative contexts also was improved with treatment. These data indicate that movement to an argument (A) position as in NP-movement is distinct from movement to a non-argument (A-bar) position, required in wh-movement. The site where movement terminates in the s-structure of noncanonical sentences appears to influence sentence production. These findings show that linguistic properties of sentences influence sentence production breakdown and recovery in aphasia.
Aphasia, Broca↗
Tutorial: an introduction to syntax.
This paper is intended as an introduction to syntax. Borrowing from Chomsky's Government & Binding and Principles & Parameters frameworks (Chomsky, 1986, 1992, 1995), various aspects of syntactic theory are described. These include lexical, functional, and phrasal categories and how they are put together into clauses and sentences, how words are represented in the mental lexicon, how lexical properties project to the syntax, and how noun phrases are assigned structural and semantic information. Additionally, how sentences that are not canonically ordered are derived and represented, how and to what do pronouns refer, and the principles that connect all these theoretical notions to form knowledge of language are described. The paper concludes with a summary of work in normal and disordered language, including treatment of language disorders, that has exploited aspects of the syntactic theory described in this paper.
Humans↗
Training wh-question production in agrammatic aphasia: analysis of argument and adjunct movement.
The present research utilized aspects of the Principles and Parameters Approach (P&PA; Chomsky, 1991, 1993) in linguistic theory as well as findings from the psycholinguistic literature as a basis for examining sentence production in aphasic individuals. We examined the production of particular wh-movement constructions--wh-questions requiring movement of an argument noun phrase (i.e., who and what questions) and those which require adjunct movement (i.e., when and where questions). Using a single-subject experimental treatment paradigm, subjects were sequentially trained to produce these wh-questions and, throughout training, generalization to untrained wh-questions relying on similar wh-movement processes was tested. As well, the influence of training on aspects of narrative and conversational discourse was examined. Seven agrammatic aphasic subjects who evinced difficulty producing (and comprehending) "complex" sentences (e.g., passives, object relative clauses, wh-questions)--sentences that involve movement of noun phrases (NPs) out of their canonical positions, leaving behind a "trace" of that movement or "gap"--participated in the study. Subjects were trained to produce wh-questions by taking them through a series of steps emphasizing the lexical and syntactic properties (e.g., thematic role assignment, movement processes, and proper selection of wh-morpheme) of declarative sentence counterparts of target sentences. Results revealed improved sentence production abilities in all subjects under study in both constrained sentence production and, importantly, in discourse tasks. The argument/adjunct distinction was observed in the sentence production recovery patterns noted in six of the seven subjects. Three of the subjects evinced correct argument movement across trained and untrained question structures when wh-questions relying on argument movement were trained; similarly, for these subjects, training structures relying of adjunct movement resulted in improved adjunct movement. Three of the remaining four subjects who required additional treatment to alleviate their wh-morpheme selection deficits, too showed covariance between argument and adjunct movement structures with each type of movement emerging across structures in temporal sequence. We discuss these data in terms of the operations necessary to produce wh-questions, the importance of considering linguistic and psycholinguistic data when designing treatment programs for language disordered patients, and the contribution that detailed recovery data can make both to understanding the nature of sentence production deficits and to issues regarding normal sentence production.
Adult↗
Prosodic influences on the resolution of temporary ambiguity during on-line sentence processing.
We present three experiments designed to investigate the role of prosody during sentence processing. The first investigated the question of whether an utterance's prosodic contour influences its comprehension on-line. We spliced the beginning and end portions of direct object and embedded clause sentences and observed the consequent effects on comprehension using a dual-task procedure to measure processing load. Our second experiment sought to determine whether the constituent structure of these sentences could be reliably predicted using prosodic information. We found that the duration and F0 contour associated with the main-clause verb and the following NP reliably distinguished between the direct object and embedded clause constructions. In the final experiment, we manipulated the duration of the main-clause verb and found that subjects used this information to guide their initial parse during on-line sentence comprehension. The need for a model of sentence processing that addresses the use of prosodic information is discussed.
Cognition↗
Electrophysiological indices of lexical processing: the effects of verb complexity and age.
To further investigate the effects that argument structure can have on language processing, reaction-time (RT) and event-related potential (ERP) data were collected for 14 younger subjects (M = 23 years) and 13 older subjects (M = 66 years). A cross-modal lexical decision (CMLD) task, involving online processing of high- and low-complexity verbs embedded in sentences, was used. Results of a baseline nonlinguistic visual ERP task indicated that the older group of subjects demonstrated significantly longer P300 latencies and significantly lower P300 amplitudes than the younger subjects. In the sentence task, younger subjects exhibited significantly higher P300 amplitudes when processing high- versus low-complexity verbs, with a similar pattern noted for the older subjects. P300 latencies were significantly shorter for the older group than the younger group. Neither P300 latencies nor RTs were significantly related to verb complexity, although medium to large effect sizes were present. Overall, these findings support earlier notions of argument structure effects.
Adult↗
Training sentence production in agrammatism: implications for normal and disordered language.
This paper presents an overview of our work concerned with treatment of sentence production deficits seen in agrammatic (Broca's) aphasic individuals. Using a single-subject experimental research paradigm, we examined emergent sentence production patterns in a subset of Broca's subjects who evinced sentence production (and comprehension) deficits involving "complex" sentences in which noun phrases (NPs) have been moved out of their canonical positions. We used aspects of Chomsky's Principles and Parameters approach of Government Binding (GB) Theory (Chomsky, 1986, Chomsky & Lasnik, 1991), as well as findings from the psycholinguistic and neurolinguistic literature as a basis for selecting sentences entered into our experiments and for designing our intervention approach, in general. Subjects were trained to produce sentences which rely on NP-movement (i.e., passives) or WH-movement (i.e., wh-questions, object clefts)--sentences formed by applying the rule "Move-alpha" in which moved constituents leave behind a "trace" or "gap" of their movement. Training emphasized the lexical and syntactic properties (e.g., thematic role assignment, NP-movement) of target sentences. Throughout this training we carefully measured generalization to untrained sentences relying on similar movement operations and error patterns were examined as they evolved over time. Results of our work indicated not only improved sentence production abilities in all subjects under study, but also--in many cases--generalization of sentence production across linguistic lines. That is, training WH-movement structures (e.g., object clefts) improved production of untrained WH-movement constructions (e.g., wh-questions) that are very different in their s-structure representation; however, no effect of this training on NP-movement structures occurred. In addition, within the class of wh-questions, generative production across questions relying on argument (direct object NP) movement (i.e., what- and who-questions) occurred in the absence of generalization to wh-questions requiring movement from adjunct position (i.e., where- and when-questions) for some subjects. For others, generalized production occurred only when wh-morphemes were the focus of treatment, indicating that at least two processes must be completed for successful wh-question production to take place: movement of the wh-item itself and control of sublexical features that determine wh-morpheme selection. These data are discussed in terms of the contribution that detailed recovery data, controlled for lexical and syntactic properties of sentence production, can make both to understanding the nature of sentence production deficits and to issues regarding normal sentence production.
Aphasia, Broca↗
Lexical properties, prosody, and syntax: implications for normal and disordered language.
This paper is primarily about sentence processing in neurologically intact subjects--but carries with it the underlying message that though both grammatical and on-line analyses of agrammatism have borne considerable fruit, there is much about the efforts from normal psycholinguistics that has yet to find its way into investigations of aphasia. We describe some of our psycholinguistic work and show how it has influenced our work in aphasia. This work involves three different kinds of information that the human sentence processing system appears to exploit: (1) lexical properties, particularly those having to do with verbs; (2) syntactic operations that connect one position in the sentence to another, nonadjacent position; and (3) prosody, which is often overlooked but which may turn out to be crucial to accounts of both normal and disordered sentence processing. Finally, we suggest that lexical properties interact with prosody to help the parser in its initial analysis.
Aphasia, Broca↗
On-line comprehension of VP-ellipsis: syntactic reconstruction and semantic influence.
We describe two experiments that explored the on-line processing of coordinated (e.g., The policemen defended himself and the fireman did [e] too, according to someone who was there) and subordinated VP-ellipsis (e.g., The policeman defended himself because the fireman did [e], according to someone who was there). Such constructions have two possible interpretations: The "sloppy" reading is that the fireman defended himself, where himself corefers with the fireman. The "strict" reading is that the fireman defended him, where him corefers with the policeman. In our experiments we examined the strict reading, and found different time courses of processing the coordinated and subordinated structures. In coordination we found immediate reaccess of the nonlocal subject at the gap. In subordinated structures we found the reaccess effect only downstream from the gap. We interpret these patterns as reflecting the automatic nature of gap filling in coordinated ellipsis, but in subordinated ellipsis a causal relation must be computed between the two clauses, " drawing out" reaccess of the filler.
Humans↗
Prosody and the processing of filler-gap sentences.
This study was designed to explore the effects of linguistic prosody on the processing of "filler-gap" sentences. We designed two experiments to determine first whether the sentence processor uses information contained in the prosodic contour of an utterance during on-line processing, and second the form that information may take. In Experiment 1, we found that prosody apparently influences when listeners posit gaps on-line. In Experiment 2, we obtained acoustic evidence that gaps are represented in the prosodic contour of an utterance. The results of this study support a view in which prosody contributes very early to on-line structure building mechanisms during sentence processing.
Cognition↗
Verb-argument structure processing in complex sentences in Broca's and Wernicke's aphasia.
We describe three experiments that explore the real-time access of verb-argument structures in a group of normal control subjects, a group of Broca's aphasic patients, and a group of Wernicke's aphasic patients. Specifically, we examine whether our subjects exhaustively access the thematic representations of verbs in active, passive, cleft-subject, and cleft-object sentences. We find that our normal control subjects and Broca's aphasic patients are sensitive to the thematic properties of verbs, regardless of sentence type. Our Wernicke's aphasic patients do not show on-line sensitivity to this lexical property. We discuss these results in terms of multiple resources dedicated to specific sentence processing devices, a possible semantic deficit in Wernicke's aphasia, and a double-dissociation between the operation of accessing a verb's thematic properties and the operation of computing the trace-antecedent relation.
Aged↗
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.
Alcohol Amnestic Disorder↗
Lexical argument structure representations and their role in translation across cognitive domains.
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Attention↗
Verb effects during sentence processing.
We describe a study that explores how the properties of a verb's lexical entry contribute to on-line sentence processing. Schmauder (1991) has recently suggested that the verb-processing effects shown previously by Shapiro and his colleagues (Shapiro & Levine, 1990; Shapiro, Zurif, & Grimshaw, 1987; 1989) are not generalizable and may have been artifacts precipitated by experimental design factors. In this paper we logically analyze such a possibility and then present experiments that systematically investigate the design differences between the Shapiro et al. studies cited above and the Schmauder study. These analyses and experiments provide further evidence that verb effects during sentence processing are real, are to be expected given the architectures of recent parsing models, and are replicable using a dual task that is modified in reasonable ways.
Humans↗