To cite this Article Hagoort, Peter , Brown, Colin and Groothusen, Jolanda(1993) Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.'The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. , 1993,8 (4) This paper presents event-related brain potential (ERP) data from an experiment on syntactic processing. Subjects read individual sentences containing one of three different kinds of violations of the syntactic constraints of Dutch. The ERP results provide evidence for M electrophysiological response to syntactic processing that is qualitatively different from established ERP responses to semantic processing. We refer to this electrophysiological manifestation of parsing as the Syntactic Positive Shift (SPS). LANGUAGE AND COGNITIVE PROCESSESThe SPS was observed in an experiment in which no task demands, other than to read the input, were imposed on the subjects. The pattern of responses to the different kinds of syntactic violations suggests that the SPS indicates the impossibility for the parser to assign the preferred structure to M incoming string of words, irrespective of the specific syntactic nature of this preferred structure. The implications of these findings for further research on parsing are discussed.

The authors examined whether people can use their knowledge of the wider discourse rapidly enough to anticipate specific upcoming words as a sentence is unfolding. In an event-related brain potential (ERP) experiment, subjects heard Dutch stories that supported the prediction of a specific noun. To probe whether this noun was anticipated at a preceding indefinite article, stories were continued with a gender-marked adjective whose suffix mismatched the upcoming noun's syntactic gender. Predictioninconsistent adjectives elicited a differential ERP effect, which disappeared in a no-discourse control experiment. Furthermore, in self-paced reading, prediction-inconsistent adjectives slowed readers down before the noun. These findings suggest that people can indeed predict upcoming words in fluent discourse and, moreover, that these predicted words can immediately begin to participate in incremental parsing operations.

The N 4 0 0 is an endogenous event-related brain potential (ERP) that is sensitive to semantic processes during language comprehension. The general question we address in this paper is which aspects of the comprehension process are manifest in the N 4 0 0 . The focus is on the sensitivity of the N 4 0 0 to the automatic process of lexical access, or to the controlled process of lexical integration. The former process is the reflex-like and effortless behavior of computing a form representation of the linguistic signal, and of mapping this representation onto corresponding entries in the mental lexicon. The latter process concerns the integration of a spoken or written word into a higher-order meaning representation of the context within which it occurs. ERPs and reaction times (RTs) were acquired to target words preceded by semantically related and unrelated prime words. The semantic relationship between a prime and its target has been shown to modulate the amplitude of the N 4 0 0 to the target. This modulation can arise from lexical access processes, reflecting the automatic spread of activation between words related in meaning in the mental lexicon. Alternatively,

In two ERP experiments we investigated how and when the language comprehension system relates an incoming word to semantic representations of an unfolding local sentence and a wider discourse. In Experiment 1, subjects were presented with short stories. The last sentence of these stories occasionally contained a critical word that, although acceptable in the local sentence context, was semantically anomalous with respect to the wider discourse (e.g., Jane told the brother that he was exceptionally slow in a discourse context where he had in fact been very quick). Relative to coherent control words (e.g., quick), these discourse-dependent semantic anomalies elicited a large N400 effect that began at about 200 to 250 msec after word onset. In Experiment 2, the same sentences were presented without their original story context. Although the words that had previously been anomalous in discourse still elicited a slightly larger average N400 than the coherent words, the resulting N400 effect was much reduced, showing that the large effect observed in stories depended on the wider discourse. In the same experiment, single sentences that contained a clear local semantic anomaly elicited a standard sentence-dependent N400 effect (e.g., Kutas & Hillyard, 1980). The N400 effects elicited in discourse and in single sentences had the same time course, overall morphology, and scalp distribution. We argue that these ndings are most compatible with models of language processing in which there is no fundamental distinction between the integration of a word in its local (sentence-level) and its global (discourse-level) semantic context.

In a semantic priming paradigm, the effects of different levels of processing on the N400 were assessed by chang ing the task demands. In the lexical decision task, subjects had to discriminate between words and nonwords, and in the physical task, subjects had to discriminate between uppercase and lowercase letters. The proportion of related versus unrelated word pairs differed between conditions. A lexicality test on reaction times demonstrated that the physical task was performed nonlexically. Moreover, a semantic priming reaction time effect was obtained only in the lexical decision task. The level of processing clearly affected the event-related potentials. An N400 priming effect was only observed in the lexical decision task. In contrast, in the physical task a P300 effect was observed for either related or unrelated targets, depending on their frequency of occurrence. Taken together, the results indicate that an N400 priming effect is only evoked when the task performance induces the semantic aspects of words to become part of an episodic trace of the stimulus event.Descriptors: Levels of processing, Semantic priming, N400, P300In this study, we investigated the influence of task demands on the N400 semantic priming effect. In particular, we focused on the impact on the N400 of different levels of processing of lexical stimuli. In this report, we first discuss the relevant semantic prim ing effects and the mechanisms responsible for these priming effects then we introduce the levels of processing framework within which semantic priming effects were investigated.One of the most consistent findings in the psycholinguistic literature is that words are processed faster and more accurately when they are preceded by a semantically related or associated word than by an unrelated word (e.g., Meyer & Schvaneveldt, 1971; see Neely, 1991, for a review). More recently, it has been demonstrated that semantic priming effects can also be recorded with the use of the event-related brain potential (ERP) method. Hillyard (1980, 1984) identified an ERP component, the N400, a negative peak with a mean latency of 400 ms and a centroparietal distribution, that is larger in amplitude for words that are semantically incongruent with a preceding sen tence context. Subsequent research has shown that the N400 is tied more to semantic expectancy than to anomaly (e.g., Kutas, Lindamood, & Hillyard, 1984).

An event-related brain potentials experiment was carried out to examine the interplay of referential and structural factors during sentence processing in discourse. Subjects read (Dutch) sentences beginning like "David told the girl that . . . " in short story contexts that had introduced either one or two referents for a critical singular noun phrase ("the girl"). The waveforms showed that within 280 ms after onset of the critical noun the reader had already determined whether the noun phrase had a unique referent in earlier discourse. Furthermore, this referential information was immediately used in parsing the rest of the sentence, which was briefly ambiguous between a complement clause (" . . . that there would be some visitors") and a relative clause (" . . . that had been on the phone to hang up"). A consistent pattern of P600/SPS effects elicited by various subsequent disambiguations revealed that a two-referent discourse context had led the parser to initially pursue the relative-clause alternative to a larger extent than a one-referent context. Together, the results suggest that during the processing of sentences in discourse, structural and referential sources of information interact on a word-by-word basis. © 1999 Academic Press Key Words: discourse context; referential ambiguity; parsing; syntactic ambiguity resolution; ERP.When we read a book or listen to speech in our native language, we usually have a sense of immediate understanding, of recognizing and interpreting every word as soon as we see or hear it. Psycholinguistic experiments have to a large extent confirmed this intuition, by showing that as a sentence unfolds over time, every new word is related to the local sentence context within only a few hundred milliseconds, both in terms of its syntactic features ("parsing") and in terms of its semantics. To extract the syntactic and semantic structure of a given sentence is, however, only part of what it means to comprehend. Sentences almost invariably occur in discourse and can only be properly understood in the context of what has been said before (Clark, 1996). In a coherent text or conversation, the definite NPs in an utterance like They told the girl that the house was gone, for example, are all likely to refer to entities introduced before. Without identifying those referents, what is said cannot be related to what is already known, and sentence meaning is left in mid-air.The present study examined two closely related aspects of processing sentences in discourse. First, we examined the speed and incrementality of the mechanisms involved in referent identification-do these also deliver their output within only a few hundred milliseconds after a relevant word or do they for some reason substantially lag behind the processes that recover syntactic and semantic structure? Second, can the results of referential processing-if delivered quickly enough-guide the further analysis of sentence structure, i.e., parsing?We thank Karin Remmerswaal and John Haasen for help in running the experiment and...

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In this study, event-related brain potential e ects of speech processing are obtained and compared to similar e ects in sentence reading. In two experiments sentences were presented that contained three di erent types of grammatical violations. In one experiment sentences were presented word by word at a rate of four words per second. The grammatical violations elicited a Syntactic Positive Shift (P600/SPS), 500 ms after the onset of the word that rendered the sentence ungrammatical. The P600/SPS consisted of two phases, an early phase with a relatively equal anterior±posterior distribution and a later phase with a strong posterior distribution. We interpret the ®rst phase as an indication of structural integration complexity, and the second phase as an indication of failing parsing operations and/or an attempt at reanalysis. In the second experiment the same syntactic violations were presented in sentences spoken at a normal rate and with normal intonation. These violations elicited a P600/SPS with the same onset as was observed for the reading of these sentences. In addition two of the three violations showed a preceding frontal negativity, most clearly over the left hemisphere. 7