句子加工中的语义P600效应

句子加工领域的研究中,一般认为,N400效应与语义加工有关,句法违反通常引发P600效应。然而近年来一些研究发现,句子语义违反时也引发了P600效应,即语义P600效应。对语义P600效应的诱发原因及其功能意义,目前有三种代表性的解释:监控说认为,P600效应是由语言理解过程中的认知冲突引发的,反映了认知监控系统对可能出现的加工错误的检测与解决;而非句法中心动态模型认为语义P600效应反映的是句子理解过程中两条通路之间出现冲突时的持续分析;扩展的论元依赖模型则用新的句子加工模型来解释语义P600效应,认为语义P600效应与句法违反引发的P600效应产生于句子加工的不同过程。     

汉语句子加工中句法信息与语义信息的交互作用：来自ERP的证据

采用ERP技术考察句子加工过程中句法信息和语义信息交互作用的时间进程。以汉语“把字句”为实验材料,分别比较句法违例句与双重违例句的LAN和P600效应、语义违例句与双重违例句的N400效应。与句法违例句相比,双重违例句的LAN效应的波幅更负,潜伏期更长,皮层分布更广泛;双重违例句的P600效应出现减弱趋势;双重违例句的N400效应的潜伏期显著长于语义违例句。结果表明,在句子加工的各个阶段,句法信息和语义信息呈持续交互作用,支持句子的平行加工模型。     

语义信息复杂度对二语者英语被动句加工的影响

采用英语所独有且非常重要的句法结构——被动语态作为语言材料,选取某些可以在句子中的词汇顺序基本没有变化的情况下转换为汉语句式（汉语“被”字句）的“直译型”被动句以及必须根据其意义进行句式转换方能形成相应的汉语句式（汉语主动句）的“意译型”被动句作为实验材料,探讨了在动词语义复杂条件下二语熟练度（包括晚期中等熟练者和高熟练者）对被动句加工过程的影响。结果表明：高熟练者正确率均高于中等熟练者,说明在动词语义复杂的情况下熟练度依然可以预测英语被动句实时加工的程度和水平。此时,语义违例的正确率最高、反应时最短,句法违例句则与之相反。双违例引发的N400效应显著,正确句和句法违例均未引发负向的N400;高熟练者P600的波幅明显高于中等熟练者,句法违例和双违例引发的P600效应最显著。行为指标支持语言间句法加工相似性效应——直译句反应快、正确率高。ERP数据则得出了与之相反的结果：直译句比意译句诱发出更大的N400效应,意译句则引发了较大的P600。上述结果进一步说明二语熟练度对语言间句法加工相似性效应具有很强的调节作用。     

中国二语学习者英语句子加工的心理机制初探:以主动句为例

操纵不同违例类型（语义单违例、句法单违例、双违例）及不同的违例词位置（句中、句尾）,运用ERPs技术初步探讨了中国大学生二语（英语）学习者英语简单句的心理加工过程。结果发现,中间句法单违例诱发了早期左前负波（ELAN）,句尾句法单违例引发了正波（P600）。句尾语义单违例诱发的负波（N400）波幅显著大于中间语义单违例。即存在违例关键词的位置效应。较之单违例,语义-句法双违例诱发的N400与P600波幅变化呈非对称性。语义-句法双违例句诱发的P600波幅大于句法单违例句;语义-句法双违例引发的N400波幅均小于语义单违例句。这说明句法与语义加工之间存在交互作用,句法加工在很大程度上受到语义加工的影响,句法加工对语义加工的影响较小。     

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     

句子语境中语义联系效应和句法效应的研究

通过对比研究句子语境中句法成分和语义联系对目标词加工的不同影响,来探讨句子语境的作用机制和作用点问题。实验一采用词汇命名任务研究发现,句法违反对词汇命名会产生抑制作用,而语义违反对词汇命名却没有发现抑制作用。实验二利用词汇决定任务发现,句法和语义成分影响词汇决定任务,句法违反和语义违反对词汇决定任务均会产生抑制作用。结果表明,句子语境加工中,对内容词语义整合过程中存在一个句法成分的独立加工水平。     

句子阅读理解过程中句意的建构时间

一般语言学理论认为, 在句子阅读理解过程中, 句子意义建构是基于词汇语义整合的, 其反映在N400之上, 开始于词语呈现后约250 ms。然而, 近年关于语义P600效应的研究却提示句意建构可能存在多通道或方式, 读者甚至可能在N400反映的加工出现之前就已建立了初步句意。为探明在句子阅读理解过程中是否存在比N400反映的加工更早的句意建构, 以及如果存在这样的句意建构, 其是从何时开始的, 本研究开展了四个实验。实验1发现被试在句末双字词呈现200 ms后已将其联系到上文语义表征而建立了句意, 提示句意建构开始于N400反映的加工出现之前。实验2与3进一步发现, 读者开始建立句意的时间约在句末词呈现了150 ms之时。实验4排除了实验1~3效应的其他一些可能解释, 提升了实验1~3结果的可靠性。总体上, 本研究提示：在句子阅读理解过程中, 读者在句末双字词呈现了约150 ms之时就已建立了句意; 可能存在比N400反映的加工更早的句意建构。     

句法歧义句理解加工中的语义关联性效应研究

通过实验探讨了汉语直接宾语(DO)/宾语小句(SC)类暂时句法歧义句理解加工中的语义关联性效应。实验采用自定速动窗技术。实验1发现在汉语暂时句法歧义句理解加工中存在语义关联性效应。实验2发现语义关联性与句法歧义性因素在解歧区产生了显著的交互作用。结果表明,语义关联性因素显著影响对句子的理解加工,并且与句法歧义因素共同作用于句子的理解加工过程。     

词汇共现频率视角下语义联想效应及其神经机制

词汇识别与记忆受到词汇之间语义联想关系的影响。鉴于自由联想方法建立词汇语义联想关系的局限性, 研究者们提出用共现联想法建立词汇之间的语义联想关系。本文对词汇共现频率视角下的语义联想效应及其神经机制的研究进行分析发现, 语义联想的丰富程度和关联程度影响词汇的加工; 与少语义联想词相比, 多语义联想词导致P200波幅增大和N400波幅减小; 语义联想加工涉及的脑区主要是额上回和左内侧颞叶区域。未来研究需要探讨自由联想法和共现联想法建立语义联想关系的差异, 基于共现联想法进一步地探究语义联想的行为规律和神经机制, 并从共现联想的角度开展汉语语义联想效应及神经机制的研究。     

生命性在句子加工中作用的ERP研究

生命性广泛地渗透到人类语言系统中发挥其作用。本文主要结合最新和经典的有关生命性的ERP研究探讨了生命性信息起作用的模式和时间进程。在句子加工过程中,生命性影响论元的加工并影响题元结构的建构和解释。以往研究表明,生命性违反有时引发的是N400效应,有时引发的是P600效应,少数情况还表现出N400-P600的双相模式。生命性在句子加工中的作用还跟多种变量存在交互作用,语境、题元可逆性、论元之间的语义关系、动词类型和其固有的题元结构都可能影响生命性信息起作用的模式。文章最后进行总结和展望,并提出未来研究仍有必要继续探讨生命性信息加工的时间神经动态性及其在句子加工中的具体作用机制。     

Examining the evidence for an independent semantic analyzer: an ERP study in Spanish

Recent ERP findings challenge the widespread assumption that syntactic and semantic processes are tightly coupled. Syntactically well-formed sentences that are semantically anomalous due to thematic mismatches elicit a P600, the component standardly associated with syntactic anomaly. This ‘thematic P600’ effect has been attributed to detection of semantically plausible thematic relations that conflict with the surface syntactic structure of the sentence, implying a processing architecture with an independent semantic analyzer. A key finding is that the P600 is selectively sensitive to the presence of plausible verb-argument relations, and that otherwise an N400 is elicited (The hearty meal was devouring … vs. The dusty tabletop was devouring …: Kim & Osterhout, 2005). The current study investigates in Spanish whether the evidence for an independent semantic analyzer is better explained by a standard architecture that rapidly integrates multiple sources of lexical, syntactic, and semantic information. The study manipulated the presence of plausible thematic relations, and varied the choice of auxiliary between passive-biased fue and active-progressive biased estaba. Results show a late positivity that appeared as soon as comprehenders detected an improbable combination of subject animacy, auxiliary bias, or verb voice morphology. This effect appeared at the lexical verb in the fue conditions and at the auxiliary in the estaba conditions. The late positivity elicited by surface thematic anomalies was the same, regardless of the presence of a plausible non-surface interpretation, and no N400 effects were elicited. These findings do not implicate an independent semantic analyzer, and are compatible with standard language processing architectures.     

Lexical integration: Sequential effects of syntactic and semantic information

Both semantic and syntactic context constraints can influence word processing at the level of lexical integration. In event-related brain potentials (ERPs), semantic integration is reflected by a negativity around 400 msec (N400), whereas phrase structure assignment and syntactic integration are assumed to be reflected by an early left anterior negativity and a late positivity (P600), respectively. An ERP study is presented in which participants read different types of sentences whose terminal verb was either congruent with the preceding context or incongruent due to a phrase structure violation, a semantic violation, or both. The main finding was that only the pure semantic violation condition, but not the combined semantic and syntactic violation condition, elicited a large N400. The two conditions containing phrase structure violations were predominantly characterized by a P600. Both semantic violation conditions, moreover, displayed a late negativity around 700 msec that overlapped with the P600 in the double violation condition. The absence of an N400 effect for elements that are syntactically as well as semantically incongruent with prior context suggests an early influence of phrase structure information on processes of lexical-semantic integration. The present data are discussed in comparison to previous ERP findings, and a new view of lexical integration processes is proposed.     

Is the P600/SPS affected by the richness of semantic content? A linguistic ERP study in Swedish

The study investigated whether the P600/SPS component is sensitive to the richness of semantic content in sentences. ERPs were recorded while 30 native Swedish speakers read sentences, of which half were syntactically correct and half contained a syntactic violation. Both kinds of sentences came in one of three types of descending semantic completeness: semantically coherent sentences, sentences which were incoherent due to violations of selectional restrictions, or sentences of pseudo words, hence void of lexical content. In the semantically coherent sentences a P600/SPS was found for the syntactic violation. A less salient positivity was found for the violation in the semantically incoherent sentences. No P600/SPS was found for the syntactic violation in the pseudo word sentences and no LAN component in any sentence type. The results are interpreted as supporting the hypothesis that the P600/SPS component reflects a semantically based reanalysis process.     

Making sense of sentences in schizophrenia: electrophysiological evidence for abnormal interactions between semantic and syntactic processing

Event-related potentials to critical verbs were measured as patients with schizophrenia and healthy controls read sentences word by word. Relative to their preceding context, critical verbs were (a) congruous, (b) incongruous and semantically unrelated to individual preceding words (pragmatic-semantic violations), (c) incongruous but semantically related to individual preceding words (animacy-semantic violations), or (d) syntactically anomalous. The N400 was modulated normally in patients, suggesting that semantic integration between individual words within sentences was normal in schizophrenia. The amplitude of the P600 to both syntactic and animacy-semantic violations was reduced in patients relative to controls. The authors suggest that, in schizophrenia, an abnormality in combining semantic and syntactic information online to build up propositional meaning leaves sentence processing to be primarily driven by semantic relationships between individual words.     

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.     

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.     

On the Brain Response to Syntactic Anomalies: Manipulations of Word Position and Word Class Reveal Individual Differences

In two experiments, event-related brain potentials (ERPs) were recorded from 13 scalp locations while subjects read sentences containing a syntactically or a semantically anomalous word. The position (sentence-embedded vs sentence-final) and word class (open vs closed) of the syntactic anomalies were manipulated. In both experiments, semantically anomalous words elicited an enhanced N400 component. Syntactically anomalous closed class words elicited a widely distributed late positive wave (P600) regardless of the word's position and a smaller negative-going effect that was largest over anterior sites when the anomaly occurred in sentence-final position. The response to syntactically anomalous open class words revealed striking qualitative individual differences: These words elicited a P600 response in the majority of subjects and an N400 response in others. The proportion of subjects exhibiting the N400 response was greater when the anomaly occurred in sentence-final position. These results are interpreted in the context of prior findings, and implications for the hypothesis that syntactic and semantic anomalies elicit distinct brain potentials are discussed.     

The cascaded nature of lexical selection and integration in auditory sentence processing

An event-related brain potential experiment was carried out to investigate the temporal relationship between lexical selection and the semantic integration in auditory sentence processing. Participants were presented with spoken sentences that ended with a word that was either semantically congruent or anomalous. Information about the moment in which a sentence-final word could uniquely be identified, its isolation point (IP), was compared with the onset of the elicited N400 congruity effect, reflecting semantic integration processing. The results revealed that the onset of the N400 effect occurred prior to the IP of the sentence-final words. Moreover, the factor early or late IP did not affect the onset of the N400. These findings indicate that lexical selection and semantic integration are cascading processes, in that semantic integration processing can start before the acoustic information allows the selection of a unique candidate and seems to be attempted in parallel for multiple candidates that are still compatible with the bottom-up acoustic input.     

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.