Memory for narrative and expository text: independent influences of semantic associations and text organization

The author examined memory for text in terms of the independent influences of semantic knowledge associations and text organization. Semantic associations were operationalized as the semantic relatedness between individual text concepts and the text as a whole and assessed with latent semantic analysis. The author assessed text organization by simulating comprehension with the construction integration model. Text organization consistently accounted for unique variance in recall. Semantic associations strongly predicted expository recall and predicted narrative recall significantly but to a lesser extent, even when the familiarity of the narrative content was manipulated. Results suggest that prior semantic associations and novel associations in the text structure influence memory independently, and that these influences can be affected by text genre.     

Influences of semantic and syntactic context on open- and closed-class words

Event-related potentials (ERPs) were recorded as subjects read semantically meaningful, syntactically legal but nonsensical and random word strings. The constraints imposed by formal sentence structure alone did not reduce the amplitude of the N400 component elicited by open-class words, whereas semantic constraints did. Semantic constraints also eliminated the word-frequency effect of a larger N400 for low-frequency words. Responses to closed-class words exhibited reduced N400 amplitudes in syntactic and congruent sentences, indicating that formal sentence structure placed greater restrictions on closed-class words than it did on open-class words. However, unlike the open-class results, the impact of sentence context on closed-class words was stable across word positions, suggesting that these syntactic constraints were applied only locally. A second ERP component, distinct from the N400, was elicited primarily by congruent closed-class words.     

Semantic Processing in Children and Adults: Incongruity and the N400

Semantic processing in 10-year-old children and adults was examined using event related potentials (ERPs). The N400 component, an index of semantic processing, was studied in relation to sentences that ended with congruent, moderately incongruent, or strongly incongruent words. N400 amplitude in adults corresponded to levels of semantic incongruity with the greatest amplitude occurring to strongly incongruent sentences at all midline electrodes. In contrast, children’s N400s were greater for both moderately and strongly incongruent sentences but did not differ between these levels of incongruity. This finding suggests that semantic processing may differ in adults and children.     

Event-related potential and reaction time evidence for inhibition between alternative meanings of ambiguous words

We investigated the effects of two primes that converged onto the same semantic target representation (e.g., LION-STRIPES-TIGER) or diverged onto different semantic target representations (e.g., KIDNEY-PIANO-ORGAN). Balota and Paul (1996) showed that the RT effects of two related primes in naming and lexical decision are additive, both for unambiguous and ambiguous words. Only in a relatedness judgment task ambiguous words showed underadditivity, whereas unambiguous words again showed additivity. This underadditivity was interpreted to reflect inhibition of alternative meanings of ambiguous words. In this article we tested whether inhibition occurs for N400, assumed to index postlexical integration. In lexical decision, we found additive N400 and RT effects for unambiguous and for ambiguous words. In a relatedness judgment task we observed differences between measures: (1) for unambiguous words overadditivity for N400 vs. additivity for RT; (2) although, for ambiguous words underadditivity occurred for N400 and RT, the effects were different. For RT, the alternative meaning was only less available, whereas for N400 the alternative meaning appeared completely unavailable. Our results have implications for our understanding of inhibitory processes in the processing of ambiguous words and for the functional significance of N400.     

基于语义错觉效应的句子加工探索

“语义错觉效应”是指读者在加工某些语义违例句子时,会暂时性地产生语义合理错觉,而只有通过继续加工或者再加工才能辨别出错误的现象,在脑电成分上表现为没有出现N400效应,却出现P600效应。“语义错觉效应”对传统的句子加工理论模型以及N400和P600的特异性功能意义提出了质疑。研究者在讨论此效应的基础上提出了多个句子加工模型,各模型对语义和句法加工的过程进行了探索,对语义和句法通道的关系做出了新的阐述,并对N400和P600的功能意义做出了新的解读。目前研究对N400功能的解释存在语义整合观和词汇激活观的分歧,而对P600功能的解释则从传统的句法功能转换到了更宽泛的加工过程。未来研究应关注词汇语义关系和跨语言差异,以期进一步揭示句子加工的认知及神经机制。     

Differences in the perception and time course of syntactic and semantic violations

A reading time and an ERP experiment conducted in Italian investigated the parser's responses to a syntactic violation (subject-verb number agreement) and to a semantic violation (subject-verb selectional restriction), examining the time course of comprehension processes until sentence end. The reading-time data showed that the syntactic violation was detected earlier than the semantic one and that the two violations differed in the time-course. The ERP data fully supported the reading time data: Syntactic anomalies elicited a left anterior negativity (LAN) and a P600. Semantic anomalies elicited a N400 centred on the parietal sites which started 90 ms later (latency 430 ms) than the LAN. Furthermore, the N400 evoked by the words that followed the target word continued and increased until sentence end. The results are discussed with respect to the hypotheses that the parser constructs distinct syntactic and semantic analyses of a sentence and that this characteristic holds cross-linguistically. The appropriateness of different methodologies to the study of sentence processing is also evaluated.     

The N400 and the fourth grade shift

While behavioral and educational data characterize a fourth grade shift in reading development, neuroscience evidence is relatively lacking. We used the N400 component of the event‐related potential waveform to investigate the development of single word processing across the upper elementary years, in comparison to adult readers. We presented third graders, fourth graders, fifth graders, and college students with a well‐controlled list of real words, pseudowords, letter strings, false font strings, and animal name targets. Words and pseudowords elicited similar N400s across groups. False font strings elicited N400s similar to words and letter strings in the three groups of children, but not in college students. The pattern of findings suggests relatively adult‐like semantic and phonological processing by third grade, but a long developmental time course, beyond fifth grade, for orthographic processing in this context. Thus, the amplitude of the N400 elicited by various word‐like stimuli does not reflect some sort of shift or discontinuity in word processing around the fourth grade. However, the results do suggest different developmental time courses for the processes that contribute to automatic single word reading and the integrative N400.     

Gender Electrified: ERP Evidence on the Syntactic Nature of Gender Processing

The central issue of this study concerns the claim that the processing of gender agreement in online sentence comprehension is a syntactic rather than a conceptual/semantic process. This claim was tested for the grammatical gender agreement in Dutch between the definite article and the noun. Subjects read sentences in which the definite article and the noun had the same gender and sentences in which the gender agreement was violated. While subjects read these sentences, their electrophysiological activity was recorded via electrodes placed on the scalp. Earlier research has shown that semantic and syntactic processing events manifest themselves in different event-related brain potential (ERP) effects. Semantic integration modulates the amplitude of the so-called N400. The P600/SPS is an ERP effect that is more sensitive to syntactic processes. The violation of grammatical gender agreement was found to result in a P600/SPS. For violations in sentence-final position, an additional increase of the N400 amplitude was observed. This N400 effect is interpreted as resulting from the consequence of a syntactic violation for the sentence-final wrap-up. The overall pattern of results supports the claim that the on-line processing of gender agreement information is not a content driven but a syntactic-form driven process.     

高功能孤独症者非字面语义理解缺陷：隐喻视角的ERP研究

研究采用事件相关电位技术从隐喻语义理解角度考察了高功能孤独症成人非字面语义理解中的行为特点及脑半球参与模式。行为结果显示：高功能孤独症成人对新异隐喻句的反应时最长,两类隐喻句的反应时均长于普通成人,但错误率上两组被试间无差异。脑电结果显示：高功能孤独症组对新异隐喻句的N400波幅最大,未出现半球偏侧化现象,传统隐喻句在左半球的N400波幅大于右半球,两类隐喻句的N400波幅均大于正常被试。结论：高功能孤独症成人具备隐喻理解能力,并对新异隐喻的理解做出更多努力,但右脑功能异常仍旧存在,左右半球在总体功能或神经联通性上仍旧弱于常人。     

On the locus of the semantic satiation effect: Evidence from event-related brain potentials

The present study sought to determine whether semantic satiation is merely a by-product of adaptation or satiation of upstream, nonsemantic perceptual processes or whether the effect can have a locus in semantic memory. This was done by measuring event-related brain potentials (ERPs) in a semantic word-detection task involving multiple presentations of primes and critical related and unrelated words in three experiments involving visual (Experiment 1) and auditory (Experiments 2A and 2B) stimuli. Primes varied in their type case (Experiment 1) or pitch (Experiment 2B) in order to discourage sensory adaptation. Prime satiation and relatedness of the primes to the critical word had interacting effects on ERP amplitude to critical words, particularly within the time-window of the N400 component. Because numerous studies have indicated a role for the N400 in semantic processing, modulation of the N400 relatedness effect by prime satiation (with little or no contribution from perceptual adaptation) suggests that semantic memory can be directly satiated, rather than the cost to semantic processing necessarily resulting from impoverishment of perceptual inputs.     

多媒体学习中图文加工的认知神经机制

多媒体学习的认知理论和图文理解整合模型指出, 多媒体学习中图片和文字在早期阶段的加工遵循双通道假设, 在晚期不同表征的信息进行整合完成知识建构。理论上的探讨得到了神经科学实证研究的支持。脑成像研究发现, 图、文加工在早期的前语义阶段存在差异, 但晚期的信息整合阶段共享了同一语义系统。事件相关电位研究也发现在早期图片诱发了独特的N300成分, 而晚期图、文均诱发了N400效应。尽管现有研究已经明确了图、文共享同一语义系统, 但是信息是如何在这一系统中进行整合的还需要进一步的研究。     

语篇语境对句子理解的影响：来自N400的证据

N400作为语义违反的特异性ERP组分,其波幅反映了语义整合加工过程的难度,因此可将其作为研究语篇语境意义建构过程的一项重要指标。语篇语境可分为语言语境和非语言语境。前人一系列基于语篇水平的N400研究表明,从语义的角度上看,语言语境对句子理解具有制约和协调作用,其机制涉及词汇语义启动、场景适宜性、文字内容信息以及因果推理等方面;非语言语境对句子理解具有制约和补充作用,但其机制尚不明确。两种不同来源的语义信息在实时理解中是同时得到加工的     

Iconic gestures prime related concepts: An ERP study

To assess priming by iconic gestures, we recorded EEG (at 29 scalp sites) in two experiments while adults watched short, soundless videos of spontaneously produced, cospeech iconic gestures followed by related or unrelated probe words. In Experiment 1, participants classified the relatedness between gestures and words. In Experiment 2, they attended to stimuli, and performed an incidental recognition memory test on words presented during the EEG recording session. Event-related potentials (ERPs) time-locked to the onset of probe words were measured, along with response latencies and word recognition rates. Although word relatedness did not affect reaction times or recognition rates, contextually related probe words elicited less-negative ERPs than did unrelated ones between 300 and 500 msec after stimulus onset (N400) in both experiments. These findings demonstrate sensitivity to semantic relations between iconic gestures and words in brain activity engendered during word comprehension.     

A comparison of semantic and syntactic event related potentials generated by children and adults

The present study employs event related potentials (ERPs) to verify the utility of using electrophysiological measures to study developmental questions within the field of language comprehension. Established ERP components (N400 and P600) that reflect semantic and syntactic processing were examined. Fifteen adults and 14 children (ages 8-13) processed spoken stimuli containing either semantic or syntactic anomalies. Adult participants showed a significant N400 in response to semantic anomalies and P600 components in response to syntactic anomalies. Children also show evidence of both ERP components. The children's N400 component differed from the adults' in scalp location, latency, and component amplitude. The children's P600 was remarkably similar to the P600 shown by adults in scalp location, component amplitude, and component latency. Theoretical implication for theories of language comprehension in adults and children will be discussed.     

Automatic and volitional semantic processing in aphasia.

The present study investigated the status of semantic information in aphasia by comparing the performances of aphasic and nonaphasic subjects on two tasks: an automatic semantic facilitation task and a volitional task of relatedness judgment. Both the aphasic and nonaphasic groups evidenced a semantic facilitation effect, in an on-line task of semantic processing. However, those aphasics with severe comprehension and naming disturbances (termed low comprehension aphasics) demonstrated considerable difficulty in judging the relatedness between a pictured object and members of that object's semantic field, the severity of the impairment being greater for those pictures that the low comprehension aphasics were unable to name. The pattern of results can best be explained by supposing the structural integrity of the store of semantic information in aphasia, and in particular in low comprehension aphasia: information that is retrieved and manipulated in judgment-mediated tasks with considerable difficulty.     

An electrophysiological investigation of semantic and phonological processing in skilled and less-skilled comprehenders

The most prominent theories of reading consider reading comprehension ability to be a direct consequence of lower-level reading skills. Recently however, research has shown that some children with poor comprehension ability perform normally on tests of lower-level skills (e.g., decoding). One promising line of behavioral research has found semantic processing differences between good and poor comprehenders and suggests that impoverished semantic ability may be linked to poor comprehenders' difficulties. In the current study, we used event related potentials (ERP) to compare adult skilled and less-skilled comprehenders on a set of semantic and phonological processing tasks. The results revealed that the N400 component of the ERP and the P200 component were sensitive to differences between skilled and less-skilled comprehenders during a semantic processing task. Importantly, skilled and less-skilled comprehenders showed no differences in their ERP response during a phonological processing task. These findings provide neurophysiological support for the hypothesis that less-skilled comprehenders have a weakness in semantic processing that may contribute to their comprehension difficulties.     

语言理解中语义整合的神经机制

语义整合是语言阅读理解中非常重要的环节。随着认知神经科学技术的广泛应用,当前关于语义整合的研究取得了长足进步,各种模型层出不穷。但是不同模型对于语义整合的功能定位及其内在机制却存在较大的争议。本文首先介绍当前关于语义整合的主要模型,然后对当前不同理论模型之间关于语义整合的界定,以及语义整合的功能定位是在额下回还是颞叶的争论进行了分析。我们认为,关于语义整合的实质、语义整合的功能网络将是未来研究的主要方向,相关的研究对于语言理解理论的发展将具有重要的启示。     

Semantic neighborhood effects on the recognition of ambiguous words

The effect of semantic neighborhood on the processing of ambiguous words was examined in two lexical decision experiments. Semantic neighborhood was defined in terms of semantic set size and network connectivity. In Experiment 1, the variables of semantic set size, network connectivity, and ambiguity were crossed. An ambiguity advantage was observed only within small-set low-connectivity words. In Experiment 2, the effect of network connectivity on the processing of words of high and low meaning relatedness was examined. Participants responded more rapidly to words of high meaning relatedness, relative to words of low meaning relatedness, but only within high-connectivity words. These results are interpreted within a framework in which both semantic feedback processes and meaning-level competition can affect the recognition of semantically ambiguous words.     

Effects of additional tasks on language perception: an event-related brain potential investigation

The authors investigated effects of task and overlapping processing load on semantic processing. In 3 experiments the brain potential component N400 was elicited by synonymous and nonsynonymous spoken noun pairs that were to be classified according to semantic relatedness. The time course of the N400 component to the nouns was delayed, and its amplitude was reduced when additional tasks had to be performed. The delay increased with temporal overlap and was more pronounced for language-related than for spatial additional tasks. Delays of N400 were also caused by a compatibility manipulation in the additional tasks. Theoretical accounts of the observed interference of overlapping tasks with language perception in terms of attentional shifts were discarded. Explanations in terms of resource sharing and single channel processing are discussed.     

Event-related potential sensitivity to acoustic and semantic properties of terminal words in sentences.

This experiment was concerned with the effects of phonologically correct masking on the electrophysiological responses to terminal words of spoken sentences differing in contextual constraint. Two event-related potential (ERP) components, the N400 and N200, were recorded to the terminal words of high and low constraint sentences in four conditions. In the Control condition, subjects (Ss) simply attended to the sentences with no explicit task instructions. In the Semantic condition, Ss were required to listen to the stimuli in order to make semantic judgements about the terminal word of each sentence. The Control+Masking condition was identical to the Control condition except for the simultaneous presentation of a masking stimulus. The Semantic+Masking condition had Ss listening to sentences in the presence of masking with the task of making semantic judgements about the terminal word of each sentence. ERPs were recorded from Fz, Cz, Pz, T3, and T4 in 10 subjects. Amplitudes of both the N200 and the N400 were sensitive to contextual constraint with larger responses elicited by the terminal words of low constraint sentences. In addition to demonstrating the co-occurrence of the N200 and N400, this experiment highlighted a functional separation between the two components. Masking had no statistically significant effect on N200 latency but N400 latency was delayed in the masked conditions relative to those in the unmasked conditions. It is proposed that the N200 and N400 are manifestations of two different processes; the N200 reflects the acoustic/phonological processing of the terminal word while the N400 reflects the cognitive/linguistic processing. The relationship between the N200 recorded in this experiment and the discrimination N200 is discussed.