Subject-Verb Agreement in Children and Adults: Serial or Hierarchical Processing?

Two processes, serial and hierarchical, are generally opposed to account for grammatical encoding in language production. In a developmental perspective, the question addressed here is whether the subject-verb agreement during writing is computed serially, once the words are linearly ordered in the sentence, or hierarchically, as soon as the number features are determined in a hierarchical frame. Adults and children from 3rd to 5th grades were requested to listen to sentences with built-in prepositional phrases or relative clauses and to transcribe them as quickly as possible. A serial hypothesis assumes that subject-verb agreement errors should be equally frequent with both preambles because each has the same length separating the subject head noun and the main verb. Conversely, according to a hierarchical view, errors should be more frequent with a prepositional phrase because the syntactic distance between the subject and the verb is greater than with a relative clause. The results revealed a main effect of the preamble manipulated in 5th graders and adults, but not in 3rd graders. These data were in favor of a hierarchical processing in older writers and a serial one in younger children. However, in 3rd grade, we assumed that the potential serial account was a result of the resource constraint on writing more than of a real serial processing of the agreement.     

Assessing resource demands during sentence processing in Parkinson's disease

Patients with Parkinson's disease (PD) have sentence comprehension difficulty, but it is unclear whether this is due to a deficit in grammatical processing or to an executive resource limitation. To assess grammatical processing in PD while minimizing task-related demands, PD patients and healthy control subjects performed a word detection procedure that assesses sensitivity to grammatical agreements in sentences in an "on-line" fashion. With this technique, we found that control subjects and PD patients are equally sensitive to grammatical agreement violations in sentences. A traditional, resource-demanding measure of sentence comprehension was also administered to the same PD patients. In comparison to healthy controls, PD patients were significantly impaired in their relative comprehension of sentences containing object-gap subordinate clauses compared to subject-gap subordinate clauses. Performance on several executive resource measures was also impaired in PD, and this correlated with their comprehension performance. Sensitivity to grammatical agreements with the word detection procedure, in the context of sentence comprehension difficulty on a traditional measure, suggests that PD patients' executive resource limitations contribute to their sentence comprehension difficulty.     

The retrieval of sentences from memory: A speed-accuracy study

A speed-accuracy tradeoff method was used to study the retrieval dynamics for recognition memory of parts of sentences. All sentences contained a subject, verb, object, location, and time. Recognition accuracy increased from chance at a processing time of about 0.5 sec to asymptotic accuracy at about 3 sec. The asymptotic accuracy levels for subject-verb, subject-object or verb-object recognition probes exceeded those of pair probes containing times or locations. This result suggests that the former may be more closely associated in semantic memory. The only difference among speed-accuracy curves was in asymptotic accuracy. The chance intercept and the rate of increase in accuracy were similar for all pair probes. A second finding was that the speed-accuracy curves for triple probes (e.g., subject-verb-object) were virtually identical to those of the comparable pair probes. These results appear to contradict a serial search hypothesis for the access of information from semantic memory. They support a parallel, direct-access hypothesis.     

Effects of Local and Global Context on Processing Sentences with Subject and Object Relative Clauses

An eye tracking study investigated the effects of local and global discourse context on the processing of subject and object relative clauses, whereby the contexts favored either a subject relative clause interpretation or an object relative clause interpretation. The fixation data replicated previous studies showing that object relative clause sentences were more difficult to process than subject relative sentences. Crucially, however, the reading difficulty asymmetry between subject and object relative clause sentences disappeared when the sentences were presented with a local or a global discourse context that favored the objects in the object relative clauses. These findings demonstrate that the evidence for a syntax-based account of sentence processing is found when sentences are presented in isolation. However, if sentences are placed more naturally, in context, discourse factors outweigh the initial structural assignment.     

Relative Clause Gap-Filling in Children with Specific Language Impairment

Children with Specific Language Impairment (SLI) have been observed to have production and perception difficulties with sentences containing long-distance dependencies, but it is unclear whether this is due to impairment in grammatical knowledge or in processing mechanisms. The current study addressed this issue by examining automatic on-line gap-filling in relative clauses, as well as off-line comprehension of the same stimulus sentences. As predicted by both knowledge impairment and processing impairment models, SLI children showed lack of immediate gap-filling after the relative clause verb, in comparison to a control group of typically developing children. However, on the off-line measure of comprehension of the same stimuli sentences, SLI children and TD children did not differ qualitatively. This finding is incompatible with knowledge impairment. We interpret the results to show that SLI children have impaired processing mechanisms (such as temporally delayed gap-filling) but are not impaired in their grammatical knowledge.     

The role of nonlinguistic stimuli and semantic relations in children's acquisition of grammatical utterances

Eighteen children, randomly assigned to one of six conditions, were trained in the use of two-word subject-verb (e.g. “mommy go”) utterances. The groups differed in (1) the number of different semantic relations theoretically underlying the subject-verb utterances on which the children were trained, and (2) the extent to which these semantic relations were associated with nonlinguistic events. The results indicated that the children acquired the subject-verb utterance forms more readily when they were also exposed to the events to which the utterances actually referred. Provided that the subject-verb utterances were related to ongoing events, the number of relations “underlying” these utterances did not appear critical. These results suggest that the child's acquisition of novel and grammatical utterances describing nonlinguistic stimuli highly similar to those in his natural environment are amenable to experimental control.     

The effect of noun animacy on the processing of unambiguous sentences: evidence from French relative clauses

Two experiments, one using self-paced reading and one using eye tracking, investigated the influence of noun animacy on the processing of subject relative (SR) clauses, object relative (OR) clauses, and object relative clauses with stylistic inversion (OR-SI) in French. Each sentence type was presented in two versions: either with an animate relative clause (RC) subject and an inanimate object (AS/IO), or with an inanimate RC subject and an animate object (IS/AO). There was an interaction between the RC structure and noun animacy. The advantage of SR sentences over OR and OR-SI sentences disappeared in AS/IO sentences. The interaction between animacy and structure occurred in self-paced reading times and in total fixation times on the RCs, but not in first-pass reading times. The results are consistent with a late interaction between animacy and structural processing during parsing and provide data relevant to several models of parsing.     

Processing Italian Relative Clauses: Working Memory Span and Word Order Effects on RTs

In this study, the authors aim to clarify whether the subject–object asymmetry in relative clause comprehension is due to the use of parsing strategies (Active Filler Theory) or to a greater memory load generated by object sentences. Two experiments investigate how individual differences in working memory span may influence the reading times of relative sentences in Italian, a language characterized by a flexible structure. The results of Experiment 1 indicate that object extraction is more complex than subject extraction when sentences have a canonical structure. Furthermore, low-span participants have particular difficulties with object relative sentence comprehension. The results of Experiment 2 show that subject-relative clauses with uncanonical structures are more complex to understand than object-relative clauses, and low-span participants have more difficulties than high-span participants in elaborating both subject and object relative clauses. These data seem to be coherent with the Active Filler Theory.     

Linguistic structures and mental operations

The internal representations and mental operations used in verifying a sentence against a pictorial referent are examined in an experiment where the location of the false constituent (subject, verb, or object) varied. The latencies for false sentences were ordered: verb, grammatical subject, grammatical object, with verb mismatches being detected the fastest. An information-processing analysis indicated that both comparison and search operations are employed, and that sentences are represented, in general, as a list of propositions with case-relational information. Context and task demands impose order on the list and lead to different operations on these structures. The depth of processing sentences varies from simple lexical comparisons up to full encoding and usage of syntactic and semantic features and case relations.     

Attentional resource and processing speed limitations during sentence processing in Parkinson's disease

Several studies have suggested that patients with Parkinson's disease (PD) have sentence comprehension difficulty in part because of their limited executive resources. However, these assessments confound the executive resources contributing to sentence comprehension with the resources needed for task performance. In the present study, we used a word detection technique that minimizes task demands in order to evaluate attentional and processing speed resources during the comprehension of simple sentences without subordinate clauses and sentences containing subject-relative and object-relative center-embedded subordinate clauses. We found that PD patients have poor sensitivity to phonetic errors embedded in unbound grammatical morphemes, regardless of the clausal structure of the sentence, suggesting difficulty attending to grammatical morphemes. We also found that PD patients are significantly slowed in their sensitivity to phonetic errors in content words embedded in object-relative center-embedded sentences. Slowed sensitivity to content words in object-relative sentences was correlated with timed executive measures of planning. On a traditional measure of comprehension, these PD patients were impaired for sentences containing object-relative center-embedded clauses compared to sentences with subject-relative center-embedded clauses, and comprehension of object-relative sentences was correlated with executive measures. Our findings are consistent with the claim that limited executive resources for strategic attention and processing speed contribute to the sentence comprehension difficulties of PD patients.     

The development of complex sentence interpretation in typically developing children compared with children with specific language impairments or early unilateral focal lesions

This study compared sentence comprehension skills in typically developing children 5-17 years of age, children with language impairment (LI) and children with focal brain injuries (FL) acquired in the pre/perinatal period. Participants were asked to process sentences 'on-line', choosing the agent in sentences that varied in syntactic complexity (actives, passives, subject clefts and object clefts), and in the presence or absence of a subject-verb agreement contrast. Results revealed that accuracy and processing speeds vary with syntactic complexity in all groups, reflecting the frequency and regularity of sentence types. Developmental changes continued throughout childhood, as children became faster and more accurate at processing more complex sentence structures. Children with LI and children with FL were quite profoundly delayed, displaying profiles similar to, or more impaired than those of younger children, but there was no evidence in the FL group for a disadvantage in left- vs. right-hemisphere-damaged children. Children with LI showed one unique pattern: higher than normal costs (reflected in reaction times) in using converging information from subject-verb agreement, in line with studies suggesting special vulnerabilities in grammatical morphology in this group. Results are discussed in terms of the Competition Model, a theory of language processing designed to account for the statistical changes in performance that are observed during development, and the probabilistic deficits in children with language impairments.     

Processing relative clauses varying on syntactic and semantic dimensions: An analysis with event-related potentials

Event-related potentials were used to study how parsing of German relative clauses is influenced by semantic information. Subjects read well-formed sentences containing either a subject or an object relative clause and answered questions concerning the thematic roles expressed in those sentences. Half of the sentences contained past participles that on grounds of semantic plausibility biased either a subject or an object relative reading; the other half contained past participles that provided no semantic information favoring either reading. The past participle elicited an N400 component, larger in amplitude for neutral than for semantically biased verbs, but this occurred only in the case of subject relative clauses. More specific effects were obtained only for a subgroup of subjects, when these were grouped into fast and slow comprehenders on the basis of their questionanswering reaction times. Fast comprehenders showed larger N400 amplitudes for neutral than for semantically biased past participles in general and larger N400s for the latter when there was a bias for an object relative reading as opposed to a subject relative reading. Syntactic ambiguity resolution, indicated by an auxiliary in sentence final position, was associated in this subgroup with a positive component (P345), larger in amplitude for auxiliaries indicating an object relative reading than for those indicating a subject relative reading. The latter component was independent of semantically biasing information given by a preceding past participle. Implications of these findings for models of language comprehension are considered.     

Structural characteristics of clause-containing sentences and imitation by children and adults

Children of ages 4, 6, and 8 years and college students attempted to imitate sentences containing combinations of nested and self-embedded relative clauses. Asymmetries in performance predicted from extensions of previous research were obtained at all ages. The hypothesis that these differences might be attributable to two structural characteristics of clause-containing sentences was supported by correlational analyses.This report is based on a doctoral dissertation submitted to the University of Washington.     

Producing simple utterances: Details of the planning process

Subjects produced subject-verb sentences of prespecified structure, such asThe man is kicking, in response to pictures. The amount of information required to identify the pictured actor or action and to retrieve a name for the actor was varied. The following results, based on subject response latencies, were obtained. Experiment I demonstrated that only some initial amount of verb information processing occurs before and delays the initiation of such subject-verb sentences. Experiment II demonstrated that verb information processing is initiated only after the subject of the sentence has been identified. Finally, Experiment III demonstrated that verb information processing is initiated in parallel with the retrieval of the name for the subject of the sentence.This article is based on a Ph.D. dissertation submitted to New York University.     

Extralinguistic control of language comprehension and production in the nonfluent child

The study investigated (1) the developmental progression postulated to exist between comprehension and production of sentences having the same grammatical form, and (2) the effects of syntactic, semantic, and extralinguistic variables on comprehension and production in nursery-school children. Comprehension trials required choices among four puzzle piece alternatives for which (a) both subject and object pieces differed (Phase I) or (b) only grammatical subject pictures differed (Phase II). During production trials children were asked to label preconstructed puzzles. Results indicated the comprehension-production relationship to vary as a function of age, sentence prepositions, and phases. Differential effects of semantic and extralinguistic variables during comprehension were found primarily for the youngest children, suggesting that logical relations among agent-actor-object were not sole controllers of language comprehension. Nonsyntactic control of production responses was not found.     

汉语口语句子产生的语法编码计划单元

语法编码的计划单元作为口语句子产生领域的一个重要命题,近年来备受心理语言学者的关注。本研究利用词图干扰范式下的语义效应,通过两个行为实验探讨了汉语口语句子产生中的语法编码计划单元。实验中要求被试用介词短语做主语的句子或者并列名词短语做主语的句子来命名两个竖直排列的图片,并视觉呈现干扰词。结果表明,对于两个句式而言,在第二个名词上都没有潜伏期的语义干扰效应,只有错误率上的语义干扰效应,而且这个结果并没有随着SOA(目标图片和干扰词开始呈现的时间间隔)的改变(0、150或300ms)而改变。当干扰词与图片同时呈现时(SOA=0)在并列名词短语做主语的句子中,第二个名词上出现了潜伏期的语义促进效应。这些结果说明,语法编码的说法较为宽泛,应具体描述为:词汇选择是严格递进的,而概念激活的计划单元可能是功能短语。     

Sentence comprehension and working memory limitation in aphasia: a dissociation between semantic-syntactic and phonological reactivation

The relation between working memory (WM) limitation and sentence comprehension was assessed in Hebrew-speaking aphasics, three conduction aphasics and three agrammatics. The study compared sentences that required different types of reactivation-syntactic-semantic reactivation, in relative clauses, and word form/phonological reactivation, in sentences with reanalysis of lexical ambiguity. The effect of phonological memory load, manipulated by number of words intervening between the activation and the reactivation, on comprehension of the two sentence types was examined. The findings were that agrammatic aphasics failed in the comprehension of object relatives but not on subject relatives irrespective of their antecedent-gap distance. Conduction aphasics, on the other hand, who showed severe WM limitation, comprehended well all types of relative clauses and were unaffected by antecedent-gap distance. The conduction aphasics failed to understand the sentences that required phonological reactivation when the phonological distance was long. These results suggest that the type of reactivation required by the sentence, as well as the type of memory overload are crucial in determining the effect of WM limitation on sentence comprehension.     

Judgments of grammaticality of sentences with a differing number of arguments: a comparison of English and Japanese speakers

This study explored native speakers' linguistic intuition as revealed in judging the grammaticality of sentences. Speakers of English (n = 36) and Japanese (n = 57) judged the relative grammaticality of sentences involving a verb which occurred together with one, two or three arguments. Findings showed that English speakers were more affected by the number of arguments in sentences. They judged sentences having three arguments as grammatical most often and ones having one or two arguments as grammatical less often. However, Japanese speakers gave rather similar and more grammatical judgments regardless of the number of arguments in sentences. The findings indicate a difference in tightness of argument structure in the two languages even when the sentences judged are simple sentences and they are given without any sentential context.