Understanding words in sentence contexts: the time course of ambiguity resolution

Spoken language comprehension requires rapid integration of information from multiple linguistic sources. In the present study we addressed the temporal aspects of this integration process by focusing on the time course of the selection of the appropriate meaning of lexical ambiguities ("bank") in sentence contexts. Successful selection of the contextually appropriate meaning of the ambiguous word is dependent upon the rapid binding of the contextual information in the sentence to the appropriate meaning of the ambiguity. We used the N400 to identify the time course of this binding process. The N400 was measured to target words that followed three types of context sentences. In the concordant context, the sentence biased the meaning of the sentence-final ambiguous word so that it was related to the target. In the discordant context, the sentence context biased the meaning so that it was not related to the target. In the unrelated control condition, the sentences ended in an unambiguous noun that was unrelated to the target. Half of the concordant sentences biased the dominant meaning, and the other half biased the subordinate meaning of the sentence-final ambiguous words. The ISI between onset of the target word and offset of the sentence-final word of the context sentence was 100 ms in one version of the experiment, and 1250 ms in the second version. We found that (i) the lexically dominant meaning is always partly activated, independent of context, (ii) initially both dominant and subordinate meaning are (partly) activated, which suggests that contextual and lexical factors both contribute to sentence interpretation without context completely overriding lexical information, and (iii) strong lexical influences remain present for a relatively long period of time.     

汉语歧义句的加工

通过两个实验,对汉语歧义句多种解释的意义频率和语境位置在句子歧义解析过程中的效应进行了考察。实验结果表明：（１）前语境为被试提供了某种预期信息,它对句子歧义解析的效应大于后语境;（２）在句子歧义解析过程中,不管有语境或无语境,不管是前语境或后语境,被试提取歧义句的主要意思比提取次要意思快;（３）歧义句的多种解释的激活,有一个时间进程,在短延迟间隔条件下,歧义句的主要意思可以被激活并形成表征,但次要意思的激活和表征则需要较长的时间     

Immediate disambiguation of lexically ambiguous words during reading: Evidence from eye movements

Sentences containing lexically ambiguous words were read as readers' eye movements were monitored. On half of the trials, the dominant meaning of the ambiguous word was instantiated, while in the other half, the subordinate meaning was instantiated. Furthermore, on half of the trials, an adjective or modifier immediately preceded the target noun (kitchen table, statistical table), which was consistent with either the dominant or subordinate meaning. The results of the experiment demonstrate that readers are able to immediately utilize the modifier to select the appropriate meaning of the ambiguous word.     

韵律对指代歧义的解歧作用及其机制

研究了韵律特征对指代歧义的解歧作用及其机制。所选的指代歧义句先由 33名被试确定其主要意思和次要意思。歧义句由 8名发音人朗读 ,经专家和普通听者评定后选出 1人的语料为实验材料。各有 12名在校大学生参加了重音听辨实验和名词互换语义判断实验。实验 1请被试比较歧义句中切分出来的所指名词与非所指名词的重读程度。实验 2中将不同的名词组合嵌入到主要意思与次要意思的句子框架中 ,请被试判断合成句表达的是主要意思还是次要意思。实验 3对 4名发音人的语料进行了声学分析 ,测量并比较了歧义句中的所指名词和非所指名词的音高、时长和音强。结果表明 ,韵律信息对于指代歧义有较好的解歧效果 ,消解指代歧义的基本手段是在所指名词上设置重音 ,其主要的声学表现是所指名词时长的延长。     

Event-related potentials indicate context effect in reading ambiguous words

The aim of the study was a comparison of lexical and contextual factors in understanding ambiguous words in German. First, a sample of native speakers selected 56 words having maximally strong differences between a dominant and a subordinate meaning. After this, another sample from the same population was visually presented with sentences that activated dominant or subordinate meanings of the words and were accompanied by probes associated with dominant or subordinate meanings. This resulted in a crossed design with two factors: sentence dominant vs. sentence subordinate and probe dominant vs. probe subordinate. An analysis of event-related brain potentials revealed a large, long-lasting and highly-significant N400 wave whenever the meaning of the probe was incongruent with the meaning of the sentence and the lack of this wave whenever the two meanings were congruent. In the typical N400 space and time, the effect was independent of whether the lexical word meaning was dominant or subordinate. At other sites and times, however (e.g., at lateral frontal electrodes F7/F8, and after 700 ms), the congruence effect was significant after dominant sentences only. The data indicate that lexical factors have a rather limited influence on the activation of a particular meaning of ambiguous words. A strong context can virtually override even a very strong difference in the preference for different meanings.     

Selection mechanisms in reading lexically ambiguous words

Readers' eye movements were monitored as they read sentences containing lexically ambiguous words. The ambiguous words were either biased (one strongly dominant interpretation) or nonbiased. Readers' gaze durations were longer on nonbiased than biased words when the disambiguating information followed the target word. In Experiment 1, reading times on the disambiguating word did not differ whether the disambiguation followed the target word immediately or occurred several words later. In Experiment 2, prior disambiguation eliminated the long gaze durations on nonbiased target words but resulted in long gaze durations on biased target words if the context demanded the subordinate meaning. The results indicate that successful integration of one meaning with prior context terminates the search for alternative meanings of that word. This results in selective (single meaning) access when integration of a dominant meaning is fast (due to a biasing context) and identification of a subordinate meaning is slow (a strongly biased ambiguity with a low-frequency meaning).     

Activation of shape and semantic information during ambiguous homophone processing: eye tracking evidence from Hindi

In two visual world eye tracking studies, we examined the activation of subordinate meanings of ambiguous homophones in Hindi and particularly when the sentence context is biased towards the dominant meaning. Participants listened to sentences that were either neutral or biased towards the dominant meaning of the homophone and saw a display containing four pictures. In experiment 1, the display had a shape competitor of the subordinate meaning of the homophone in both neutral and biased conditions along with three unrelated distractors. Experiment 2 had semantic competitors of the subordinate meaning of the homophones along with three distractors. Proportion of fixations to different objects overtime suggested that participants activated the subordinate meanings and oriented their attention to the shape and semantic competitors even when the prior context was biased towards the dominant meaning. Overall, these data from Hindi provide further support to those models of lexical access that assume exhaustive access of both the meanings of an ambiguous homophone. These data suggest even a dominant bias does not eliminate the activation of perceptual and conceptual features of the subordinate meaning.     

The return of “visiting relatives”: Pragmatic effects in sentence processing

Two experiments were performed to investigate the role of syntactic and pragmatic cues on the disambiguation of noun phrases of the form VERB+ing NOUN+s, like visiting relatives, that can be interpreted as either singular or plural noun phrases. Both experiments used a self-paced reading task in which reading times were measured for two words, a verb and an adverb, immediately following the potentially ambiguous noun phrase. The interpretation of the noun phrase as singular or plural was biased by pragmatic cues in the first experiment and by syntactic cues in the second experiment. In both experiments, subjects were faster to read the adverb following the verb when the interpretation biased by the cues agreed in number with the verb that immediately followed the target noun phrase than when it did not agree with the verb. These results suggest that pragmatic cues, like syntactic cues, can be utilized rapidly in sentence processing.     

Biasing thematic contexts for ambiguous sentences in a dichotic listening experiment

In an experiment derived from Lackner and Garrett (1972) 80 subjects were given a dichotic listening task where they were presented with ambiguous sentences to an attended ear and disambiguating sentences to the other, unattended, ear. Each of the sentences was preceded by a thematic context that was biased for one meaning of the ambiguous sentence. In one-half of the instances the contexts biased a meaning consistent with that of the disambiguating sentence, and in the remaining one-half they biased the meaning of the ambiguous sentence in a way that was inconsistent with the meaning of the ambiguous sentence. The meanings of the ambiguous sentences the subjects perceived tended to be those that were consistent with the biasing context, even when that meaning was inconsistent with the meaning of the disambiguating sentence. Therefore, when ambiguous sentences are preceded by a thematic context, a single-reading explanation of the processing is more appropriate than a multiple-reading explanation.     

无语境条件下汉语词类歧义词的意义激活

以单字词为实验材料,采用启动命名任务,在孤立词条件下考察了汉语词类歧义词不同意义激活的时间进程特点。实验发现,歧义词的两种意义都能被激活,但主要意义激活得较早,次要意义激活速度较慢;当两种意义都激活之后,次要意义的激活水平降低,而主要意义仍维持在一定激活水平。结果表明,汉语词类歧义词的多重激活过程会受到意义相对频率的影响。     

Processing novel compounds: Evidence for interactive meaning activation of ambiguous nouns

In three experiments, the meaning activation of ambiguous nouns in novel nominal compounds was investigated. Ambiguous nouns were unbalanced homographs occurring as the second members of the compound. Meaningful interpretations of the compounds were based on either the dominant or the subordinate meaning of the ambiguous noun. In Experiment 1, visually presented novel compounds serving as primes were followed at varying intervals by targets associatively related to distinct meanings of the ambiguous noun. In a lexical decision task, facilitation effects were found only for targets related to the meaning that was relevant for the interpretation of the compound. Experiment 2 showed that interactive activation could not be attributed to differences in semantic relatedness between the first members of compounds and targets. Experiment 3 demonstrated equal intralexical relatedness between members for both types of compounds. It is proposed that interactive activation may facilitate the interpretation of the novel compound. Compatible meaning aspects of the nouns may become more strongly activated, and incompatible meaning aspects may not become activated. The selection of meaning aspects relevant for interpretation would thereby be simplified.     

Global context effects on processing lexically ambiguous words: Evidence from eye fixations

Readers' eye movements were monitored as they read biased ambiguous target words in the context of a short paragraph. Two aspects of context were manipulated. The global context was presented in the topic sentence of the paragraph and instantiated either the dominant or the subordinate meaning of biased ambiguous target words (those with highly dominant meanings). Local contextual information either preceded or followed the target word and was always consistent with the subordinate interpretation. Consistent with prior research, we obtained a subordinate bias effect wherein readers looked longer at the ambiguous words than control words when the preceding context instantiated the subordinate meaning. More importantly, the magnitude of the subordinate bias effect was the same when global context alone, local context alone, or local and global context combined were consistent with the subordinate meaning of the ambiguous word. The results of this study indicate that global contextual information (1) has an immediate impact on lexical ambiguity resolution when no local disambiguating information is available, (2) has no additional effect when it is consistent with local information, but (3) does have a slightly delayed effect when inconsistent with local information.     

汉语同形歧义词歧义消解的两半球差异

实验探讨汉语同形歧义词(homographs)歧义消解的过程及大脑两半球的差异。被试为华中科技大学96名大学生,实验采用词汇判断任务。句子语境呈现在被试的视野中央,探测词在SOA(stimulus onset asynchronism)为100毫秒或400毫秒时呈现在左视野或右视野。结果发现,(1)当SOA为100毫秒时,在左视野(右半球)上,与语境一致的同形歧义词的主要意义得到激活,与语境不一致的次要意义也有一定程度的激活。在右视野(左半球)上,只有与语境一致的同形歧义词的主要意义得到激活。(2)当SOA为400毫秒时,在左、右视野(两半球)上,与语境一致的同形歧义词的主要意义和次要意义都得到激活。结果表明,大脑左半球对汉语歧义词的歧义消解具有一定的优势,语境敏感模型可以较好地解释本实验的结果。     

Overt reanalysis strategies and eye movements during the reading of mild garden path sentences

In an eye movement experiment, we examined the use of reanalysis strategies during the reading of locally ambiguous but globally unambiguous Spanish sentences. Among other measures, we examined regressive eye movements made while readers were recovering in reading mild garden path sentences. The sentences had an adverbial clause that, depending on the mood (indicative vs. subjunctive) of the subordinate clause verb, could attach high (to the main verb of the sentence) or low (to the verb in the subordinate clause). Although Spanish speakers favor low attachment, the high attachment version was quite easy to understand. Readers predominately used two alternative strategies to recover from the mild garden path in our sentences. In the more common reanalysis strategy, their eyes regressed from the last region (disambiguation+ 1) directly to the main verb in the sentence. Following this, they reread the rest of the sentence, fixating the next region and the adverb (the beginning of the ambiguous part of the sentence). Less frequently, readers regressed from the last region (disambiguation+1) directly to the adverb. We argue that both types of strategies are consistent with a selective reanalysis process as described by Frazier and Rayner (1982).     

Effects of sentential context on the processing of unambiguous words by the two cerebral hemispheres

The effect of sentence context on the processing of different aspects of meaning of unambiguous nouns by the two cerebral hemispheres was examined. Participants performed a lexical decision task on target words following two primes, an unambiguous noun preceded by an incomplete sentence. Priming sentences were consistent with either the dominant or the subordinate aspect of meaning of their final unambiguous word. Short and long SOAs were used. A principal finding of this study was that, when compared to unrelated aspects of meaning, for both the short and the long SOAs, the dominant and subordinate aspects of meaning of the unambiguous words were activated regardless of context in both hemispheres. However, the activation of the subordinate aspect of meaning of unambiguous words appears to be more sensitive to sentential context, especially when the unambiguous word is being processed by the left hemisphere.     

Negative Cueing Effects with Weak and Strong Intralist Cues

In three experiments, we studied cueing effects of relational and itemspecific information after enacted and non-enacted encoding of short sentences (e.g. lift the pen, fold the paper). In Experiment 1, all subjects were instructed at encoding to remember only the nouns of these sentences; half of the subjects were informed about the categorical nature of the nouns, whereas the other half were not. At retrieval, all subjects were given a free recall test and a cued recall test with the verb of each sentence as the cue. In Experiment 2, all subjects were instructed at encoding to remember the whole sentence; as in Experiment 1, half of the subjects were informed about the categorical nature of the nouns and half were not. At test, all subjects were given two cued recall tests, one categorical cue for each noun in the first test and one verb cue and one categorical cue for each noun in the second test. In Experiment 3, at encoding, all subjects were informed about the categorical nature of nouns and were instructed to remember the whole sentence. In this experiment, the actions were performed with imaginary objects; free recall and cued recall tests were given to different subjects. In all three experiments, there was a negative effect of intralist cueing with verbs. This finding is at odds with the Encoding Specificity Principle, which assumes facilitation of cueing at retrieval if the cues were encoded together with the to-be-remembered information at encoding. Also, the effect of intralist cueing was different after encoding with enactment than after encoding without enactment; this difference holds true for enactment with real objects but not for enactment with imaginary objects. Enactment increased both the relational and the item-specific cueing efficiency. The results are discussed in terms of encoding interference between cues and targets and between item-specific processing and relational processing. Enacted encoding is conceived as integrating episodic information both with respect to item specificity and relational aspects of the information.     

Sentential and discourse topic effects on lexical ambiguity processing: an eye movement examination

Models of lexical ambiguity resolution posit a role for context, but this construct has remained relatively undefined in the literature. The present study isolated two different forms of contextual constraint and examined how these sources of information might differentiate between a selective access and a reordered access model of ambiguity processing. Eye movements were monitored as participants read passages that contained either a balanced or a biased ambiguous word. The sentence containing the ambiguous word was held constant and instantiated either the subordinate meaning (Experiment 1) or the dominant meaning (Experiment 2) through the use of local context. These sentences were embedded in passages in which the topic was consistent, inconsistent, or neutral with respect to the meaning biased by the critical sentence. Experiment 1 provided evidence suggesting that the subordinate meaning of an ambiguous word was not selectively accessed even when sentence and discourse topic information biased that meaning. The data from Experiment 2 provided evidence that even the dominant meaning was not selectively accessed. These contextual sources of information were evaluated in terms of the roles they play in models of lexical ambiguity resolution.     

Lexical information in sentence comprehension

An experiment was constructed testing predictions derived from the mental model theory. According to this theory, individual words in a sentence provide clues to the building of the mental model of the sentence and need to be interpreted in relation to general knowledge of situations similar to those described in the sentence. After reading a sentence, subjects had to produce, as quickly as possible, one aspect of the meaning of a target noun. The sentence either did or did not contain the target noun, and it primed either one aspect of its meaning or no specific aspect of it. The prediction was that the subjects would be faster and more uniform at producing the primed aspect of the target noun after a priming sentence than at producing any aspect of the noun after a non-priming sentence, and this difference would occur regardless of whether the target noun had occurred in the prior sentence. The results, which confirm the predictions, are discussed in relation to current theories of sentence comprehension.     

The influence of global discourse on lexical ambiguity resolution

The influence of global discourse on the resolution of lexical ambiguity was examined in a series of naming experiments. Two-sentence passages were constructed to bias either the dominant or the subordinate meaning of a homonym that was embedded in a locally ambiguous sentence. The results provided evidence for the immediate (0-msec interstimulus interval) resolution of lexical ambiguity and were subsequently replicated in Experiment 2, in which an 80-msec stimulus onset asynchrony exposure duration was employed for the homonyms. Strong dominant and subordinate biased discourse contexts activated only the contextually appropriate sense of a homonym. In Experiment 3, each sentence of the discourse was presented in isolation. The pattern of activation obtained in Experiments 1 and 2 was found to be contingent on the integration of the two sentences to construct an overall global discourse representation of the text. The results support a context-sensitive model of lexical ambiguity resolution.     

Hemispheric Differences in Context Sensitivity During Lexical Ambiguity Resolution

Three experiments were conducted to investigate the influence of contextual constraint on lexical ambiguity resolution in the cerebral hemispheres. A cross-modal priming variant of the divided visual field task was utilized in which subjects heard sentences containing homonyms and made lexical decisions to targets semantically related to dominant and subordinate meanings. Experiment 1 showed priming in both hemispheres of dominant meanings for homonyms embedded in neutral sentence contexts. Experiment 2 showed priming in both hemispheres of dominant and subordinate meanings for homonyms embedded in sentence contexts that biased a central semantic feature of the subordinate meaning. Experiment 3 showed priming of dominant meanings in the left hemisphere (LH), and priming of the subordinate meaning in the right hemisphere (RH) for homonyms embedded in sentences that biased a peripheral semantic feature of the subordinate meaning. These results are consistent with a context-sensitive model of language processing that incorporates differential sensitivity to semantic relationships in the cerebral hemispheres.