Syntactic complexity does not necessarily make sentences harder to understand

Researchers studying language comprehension have assumed that, all else being equal, more complex sentence constructions will take longer to process. However, results from experiments, such as the one presented in this paper, which use reading rates as the dependent measure suggest that it is the interaction of specific types of deep structure representations with their surface structure forms that accounts for fluctuations in readers' on-line processing of various sentence types. In particular, those sentences in which the deep structure direct object immediately precedes the verb in the surface structure sequence are easier for comprehenders to process. These data support a dual, parallel processing model of sentence comprehension in which lexical and morphological/relational information are processed independently.Johns Hopkins University.     

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.The work reported in this paper was supported in part by NTH grant DC00494.     

眼动分析技术在句子理解研究中的应用*

句子理解是阅读研究中的一个重要部分。研究者采用了不同的手段和任务对这一问题进行了长期的研究,其中,眼动分析技术是一种行之有效的手段。本文从句子理解的三个阶段(视觉信息的提取,句子中的词汇识别和句子整合),探讨了眼动分析技术在句子理解研究中的优势作用。在此基础之上,提出了未来使用眼动分析技术进行句子理解研究需要注意的几个问题。     

句子理解中颜色信息的心理表征

采用混合实验设计、实时和事后的句子-图片匹配范式, 以隐含物体典型颜色和非典型颜色信息的句子为实验材料, 以被试对图片的反应时间和阅读时间为因变量指标, 通过不同时间间隔的设置以及不同的实验程序, 探讨了句子理解中静态和动态颜色信息心理表征的特点。结果表明：(1)在加工时间有限的情况下, 两个加工任务是否竞争相同的认知资源是造成句-图范式下匹配易化和不匹配易化的关键因素。(2)对于句子隐含的静态颜色信息, 大脑对典型颜色信息的心理表征具有即时性和局部性, 而对非典型颜色信息的心理表征还具有非局部性的特点。(3)对于句子隐含的动态颜色信息, 大脑不能对其进行即时的心理表征, 这种动态颜色信息的心理表征是在句子阅读晚期发生的。     

Direct Evidence of Memory Retrieval as a Source of Difficulty in Non‐Local Dependencies in Language

Linguistic dependencies between non‐adjacent words have been shown to cause comprehension difficulty, compared with local dependencies. According to one class of sentence comprehension accounts, non‐local dependencies are difficult because they require the retrieval of the first dependent from memory when the second dependent is encountered. According to these memory‐based accounts, making the first dependent accessible at the time when the second dependent is encountered should help alleviate the difficulty associated with the processing of non‐local dependencies. In a dual‐task paradigm, participants read sentences that did or did not contain a non‐local dependency (i.e., object‐ and subject‐extracted cleft constructions) while simultaneously remembering a word. The memory task was aimed at making the word held in memory accessible throughout the sentence. In an object‐extracted cleft (e.g., It was Ellen whom John consulted…), the object (Ellen) must be retrieved from memory when consulted is encountered. In the critical manipulation, the memory word was identical to the verb's object (ELLEN). In these conditions, the extraction effect was reduced in the comprehension accuracy data and eliminated in the reading time data. These results add to the body of evidence supporting memory‐based accounts of syntactic complexity.     

Language comprehenders mentally represent the shapes of objects

We examined the prediction that people activate perceptual symbols during language comprehension. Subjects read sentences describing an animal or object in a certain location. The shape of the object or animal changed as a function of its location (e.g., eagle in the sky, eagle in a nest). However, this change was only implied by the sentences. After reading a sentence, subjects were presented with a line drawing of the object in question. They judged whether the object had been mentioned in the sentence (Experiment 1) or simply named the object (Experiment 2). In both cases, responses were faster when the pictured object's shape matched the shape implied by the sentence than when there was a mismatch. These results support the hypothesis that perceptual symbols are routinely activated in language comprehension.     

Sentence Comprehension Deficits in Alzheimer''s Disease: A Comparison of Off-Line vs. On-Line Sentence Processing

Two studies explored whether sentence comprehension impairments in Alzheimer's disease (AD) are due to deficits in syntactic processing or memory. Study 1 used a picture-pointing sentence comprehension task to measure the final outcome of comprehension in an off-line fashion. It showed the comprehension of 30 patients with AD to be impaired, but suggested that the deficits could not be attributed solely to syntactic impairments. Study 2 investigated the effects of memory on sentence comprehension by comparing off-line (grammaticality judgment) with on-line (cross-modal naming) language processing in 11 AD and 9 control subjects. The results revealed impaired performance in the off-line task but normal performance in the on-line task using the same sentences. Performance on the off-line task correlated with independent measures of verbal working memory. These data are used to argue that sentence comprehension impairments are related to verbal working memory deficits in AD.     

The thematic hierarchy in sentence comprehension: A study on the interaction between verb class and word order in Spanish

Linking is the theory that captures the mapping of the semantic roles of lexical arguments to the syntactic functions of the phrases that realize them. At the sentence level, linking allows us to understand “who did what to whom” in an event. In Spanish, linking has been shown to interact with word order, verb class, and case marking. The current study aims to provide the first piece of experimental evidence about the interplay between word order and verb type in Spanish. We achieve this by adopting role and reference grammar and the extended argument dependency model. Two different types of clauses were examined in a self-paced reading task: clauses with object–experiencer psychological verbs and activity verbs. These types of verbs differ in the way that their syntactic and semantic structures are linked, and thus they provide interesting evidence on how information that belongs to the syntax–semantics interface might influence the predictive and integrative processes of sentence comprehension with alternative word orders. Results indicate that in Spanish, comprehension and processing speed is enhanced when the order of the constituents in the sentence mirrors their ranking on a semantic hierarchy that encodes a verb's lexical semantics. Moreover, results show that during online comprehension, predictive mechanisms based on argument hierarchization are used rapidly to inform the processing system. Our findings corroborate already existing cross-linguistic evidence on the issue and are briefly discussed in the light of other sentence-processing models.     

A Computational Evaluation of Two Models of Retrieval Processes in Sentence Processing in Aphasia

Can sentence comprehension impairments in aphasia be explained by difficulties arising from dependency completion processes in parsing? Two distinct models of dependency completion difficulty are investigated, the Lewis and Vasishth (2005) activation-based model and the direct-access model (DA; McElree, 2000). These models' predictive performance is compared using data from individuals with aphasia (IWAs) and control participants. The data are from a self-paced listening task involving subject and object relative clauses. The relative predictive performance of the models is evaluated using k-fold cross-validation. For both IWAs and controls, the activation-based model furnishes a somewhat better quantitative fit to the data than the DA. Model comparisons using Bayes factors show that, assuming an activation-based model, intermittent deficiencies may be the best explanation for the cause of impairments in IWAs, although slowed syntax and lexical delayed access may also play a role. This is the first computational evaluation of different models of dependency completion using data from impaired and unimpaired individuals. This evaluation develops a systematic approach that can be used to quantitatively compare the predictions of competing models of language processing.     

A study of syntactic processing in aphasia II: neurological aspects

This paper presents the results of a study of the effects of left hemisphere strokes on syntactically-based comprehension in aphasic patients. We studied 42 patients with aphasia secondary to left hemisphere strokes and 25 control subjects for the ability to assign and interpret three syntactic structures (passives, object extracted relative clauses, and reflexive pronouns) in enactment, sentence-picture matching and grammaticality judgment tasks. We measured accuracy, RT and self-paced listening times in SPM and GJ. We obtained magnetic resonance (MR) and 5-deoxyglucose positron emission tomography (FDG PET) data on 31 patients and 12 controls. The percent of selected regions of interest (ROIs) that was lesioned on MR and the mean normalized PET counts per voxel in ROIs were calculated. In regression analyses, lesion measures in both perisylvian and non-perisylvian ROIs predicted performance. Patients who performed at similar levels behaviorally had lesions of very different sizes, and patients with equivalent lesion sizes varied greatly in their level of performance. The data are consistent with a model in which the neural tissue that is responsible for the operations underlying sentence comprehension and syntactic processing is localized in different neural regions in different individuals.     

The temporal structure of spoken sentence comprehension in Chinese

Three experiments with 60 native Chinese speakers were conducted to examine the temporal structure of spoken sentence comprehension in Chinese. In the two sentence-gating experiments, listeners heard sentence fragments of various sizes, either successively or individually, and decided on the agent role of the sentence. In the agent-naming experiment, listeners repeated aloud the sentence agent upon hearing the sentence. Converging evidence was derived from these experiments indicating the usefulness of sentence gating in tapping into the temporal structure of comprehension and in evaluating listeners’ comprehension on the basis of partial information. Results from these experiments show that partial sentence information plays a very important role in Chinese sentence comprehension, and that Chinese listeners integrate incomplete and ungrammatical sentence fragments by reference to complete and grammatical models in the language. It is argued that these processing characteristics reflect properties of the Chinese language in which few morphological, grammatical, and syntactic constraints are placed on the relationships between sentence constituents.     

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.     

Embodiment Effects and Language Comprehension in Alzheimer's Disease

It has been shown that when participants are asked to make sensibility judgments on sentences that describe a transfer of an object toward or away from their body, they are faster to respond when the response requires a movement in the same direction as the transfer described in the sentence. This phenomenon is known as the action compatibility effect (ACE). This study investigates whether the ACE exists for volunteers with Alzheimer's disease (AD), whether the ACE can facilitate language comprehension, and also whether the ACE can still be produced if the order of the two events is inverted, that is, whether overt movement can prime comprehension of transfer sentences. In Study 1, participants with AD, younger, and older adults were tested on an adaptation of the ACE Paradigm. In Study 2, the same paradigm was modified to include an arm movement that participants had to perform prior to sentence exposure on screen. In Study 1, young, older adults, and individuals with AD were faster to respond when the direction of the response movement matched the directionality implied by the sentence (ACE). In Study 2, no traditional ACE was found; participants were faster when the direction of the movement immediately preceding the sentence matched the directionality of the sentence. It was found that compatibility effects generated a relative advantage, that transfer schemata are easier to process, and that an ACE‐like effect can be the result of mutual priming between language and movement. Results suggested preservation in AD of the neural systems for action engaged during language comprehension, and conditions under which comprehension in AD can be facilitated in real life may be identified.     

汉语句子理解中物体隐含颜色心理模拟的ERPs研究

当前研究采用事件相关电位(ERPs)技术,同时沿用经典的句图匹配范式,考察句子理解中物体典型颜色与非典型颜色的心理加工过程在脑电活动上的反映。实验中被试先阅读句子再判断句子后呈现的图片物体是否在句子中出现过,句子中隐含的物体颜色或是关键物体的典型颜色或是非典型颜色。实验结果发现,典型颜色句子版本下句图不匹配条件比句图匹配条件引发了更大的N400效应;而非典型颜色句子版本下两者N400差异不显著。研究结果表明,人们在汉语句子理解过程中会实时对隐含的物体颜色信息进行心理模拟。并且,句子隐含物体颜色的典型性是造成匹配易化或不匹配易化的关键因素之一。     

暂时句法歧义句认知加工初探

研究通过两个实验探讨了汉语句子理解中的直接宾语（DO）／句子补语（SC）类暂时句法歧义句的认知加工特征。实验一采用自定速移动视窗技术,发现歧义句和无歧义句解歧区的阅读时间存在显著差异。实验二增加了论题适合性因素以探讨非句法信息在句子理解加工中的影响,发现论题适合性信息影响歧义区和解歧区的阅读时间。实验结果表明：在汉语句子加工中存在DO／SC暂时句法歧义效应;论题适合性信息即时参与对句子的加工,并对句法歧义效应产生影响。     

句子理解的关键——对句法和语义关系的再探讨

对于句子理解中句法和语义的关系,传统的模块化观点认为,句法信息优先于语义信息,句法加工支配着句子的理解过程。近期,这种强调句法优先的理论受到了一系列ERP（Event-related potentials）研究结果的挑战,这些研究从不同角度论证了语义信息对句法加工及句子整合加工的重要作用。基于这些研究发现,研究者提出句子理解过程中句法和语义的关系并非一成不变：一些情况下可能是句法支配语义加工,而另一些情况下则可能是语义引导句法加工     

Agrammatic Broca's aphasia is not associated with a single pattern of comprehension performance

One influential hypothesis posits that the brain regions implicated in Broca's aphasia are responsible for specific syntactic operations that are necessary for the comprehension and production of sentences (Grodzinsky, 1986, 1990, in press). The empirical basis of this hypothesis is the claim that Broca's aphasics have no difficulty understanding sentences in the active voice (and other "canonical" sentence types, such as subject relatives and clefts with negative predicates), but perform at chance level with passive voice constructions (and other "noncanonical" sentences such as object-gap relatives and object clefts). In the face of well-established results indicating that Broca's aphasics can exhibit several different performance patterns on these sentence types, Grodzinsky, Pi?ango, Zurif, and Drai (1999) argued that these conflicting results do not challenge the theory when the data are analyzed appropriately. They carried out a creative statistical analysis of the comprehension performance of published cases of Broca's aphasia and concluded that all of these cases are in agreement with the predicted pattern: chance on passives and 100% correct on actives. Here we show that the statistical reasoning adopted by Grodzinsky et al. (1999) is flawed. We also show that the comprehension performance of a substantial number of the Broca's aphasics in their own sample does not conform to the pattern required. Rather, contrary to these authors' claim, Broca's aphasia is not associated with a consistent pattern of sentence comprehension performance, but allows for a number of distinct patterns in different patients.     

Click monitoring revisited: An on-line study of sentence comprehension

Spoken sentence comprehension is based upon rapid and complex psychological processes, yielding a constantly fluctuating cognitive load. The aim of this study was to evaluate on-line click monitoring, a classical but poorly exploited experimental method, which should allow for an easy measurement of processing load at any chosen point of experimental sentences. In Experiments 1 and 2, we obtained longer latencies to clicks located at the boundary of reversible object relative clauses than to clicks identically located in subject relatives and to clicks located earlier within object relatives. Experiment 3 further revealed that this effect of syntactic type was specific to transposed object relatives and did not occur with normal object relatives. In Experiment 4, we observed longer latencies with semantically reversible than with irreversible sentences, but no difference between actives and passives. These results were obtained under strict control of potential lexical and phonological biases, and suggest that on-line click monitoring may be one useful tool in the study of sentence comprehension.     

A study of syntactic processing in aphasia I: behavioral (psycholinguistic) aspects

This paper presents the results of a study of syntactically based comprehension in aphasic patients. We studied 42 patients with aphasia secondary to left hemisphere strokes and 25 control participants. We measured off-line, end-of-sentence, performance (accuracy and reaction time) in two tasks that require comprehension--enactment and sentence-picture matching--and in grammaticality judgment, with whole sentence auditory presentation. We also used sentence-picture matching and grammaticality judgment as tasks in two self-paced listening studies with the same patients to measure on-line performance. In each task and presentation format, we presented sentences that tested the ability to assign and interpret three structural contrasts chosen to examine different basic syntactic operations: actives and passives, subject and object extracted relative clauses, and reflexive pronouns and matched sentences without these elements. We examined these behavioral data to determine patterns of impairment in individual patients and in groups of patients, using correlational analyses, factor analyses, and analyses of variance. The results showed that almost no individual patients had stable deficits referable to the ability to interpret individual syntactic structures, that a variety of structural features contributed to sentence processing complexity both on-line and off-line, that correct responses were associated with normal on-line and errors with abnormal performance, and that the major determinant of performance is a factor that affected performance on all sentence types. The results indicate that the major cause of aphasic impairments of syntactically based comprehension are intermittent reductions in the processing capacity available for syntactic, interpretive, and task-related operations.