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。     

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     

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.     

Sensitivity to local sentence context information in lexical ambiguity resolution: evidence from left- and right-hemisphere-damaged individuals

Using a cross-modal semantic priming paradigm, the present study investigated the ability of left-hemisphere-damaged (LHD) nonfluent aphasic, right-hemisphere-damaged (RHD) and non-brain-damaged (NBD) control subjects to use local sentence context information to resolve lexically ambiguous words. Critical sentences were manipulated such that they were either unbiased, or biased toward one of two meanings of sentence-final equibiased ambiguous words. Sentence primes were presented auditorily, followed after a short (0 ms) or long (750 ms) interstimulus interval (ISI) by the presentation of a first- or second-meaning related visual target, on which subjects made a lexical decision. At the short ISI, neither patient group appeared to be influenced by context, in sharp contrast to the performance of the NBD control subjects. LHD nonfluent aphasic subjects activated both meanings of ambiguous words regardless of context, whereas RHD subjects activated only the first meaning in unbiased and second-meaning biased contexts. At the long ISI, LHD nonfluent aphasic subjects failed to show evidence of activation of either meaning, while RHD individuals activated first meanings in unbiased contexts and contextually appropriate meanings in second-meaning biased contexts. These findings suggest that both left (LH) and right hemisphere (RH) damage lead to deficits in using local contextual information to complete the process of ambiguity resolution. LH damage seems to spare initial access to word meanings, but initially impairs the ability to use context and results in a faster than normal decay of lexical activation. RH damage appears to initially disrupt access to context, resulting in an over-reliance on frequency in the activation of ambiguous word meanings.     

The Effect of Non-sentential Context Prosody on Homographs’ Lexical Activation in Persian

This study examines the effect of non-sentential context prosody pattern on lexical activation in Persian. For this purpose a questionnaire including target and non-target words is used. The target words are homographs with two possible stress patterns belonging to different syntactic categories. Participants are asked to read out the words aloud and note the first word that comes to their mind. The results show that by reading the target words, both meanings of the target words are activated in mind and the prosodic pattern of the non-sentential preceding context does not affect the activation of the other stress pattern meaning. This result suggests that the metrical prosodic pattern of non-sentential context is not a strong constraint to determine which meaning of the target word must be activated. The experiment also illustrates that the stress pattern used to read the target words does not necessarily matches the stress pattern of the target word which relates to the written word. These findings confirm Swinney (Verb Learn Verb Behav 18:645–665, 1979) and Elston-Güttler and Friederici’s (J Mem Lang 52(2):256–283, 2005) finding that both meanings of an ambiguous word are accessed at the first stage. This study shows that in lack of semantic context, Persian natives behave homographs as ambiguous words and there is no bias towards preferring one meaning over another.     

词汇识别中歧义词素语义加工:ERP研究

结合掩蔽启动范式和ERP技术,利用歧义词素的加工,本研究探讨了歧义词素语义的激活。实验采用3×2两因素被试内设计,歧义词素两含义互为启动刺激和目标刺激,两变量分别为启动词类型(歧义词素含义1 vs.含义2 vs.无关词)和目标词类型(歧义词素含义1 vs.含义2)。行为结果发现启动词类型和目标词类型存在交互作用,即只有当共享词素同形同义的情况下,目标词的加工才可能被启动,共享词素同形不同义时并没有产生启动效应。ERP结果进一步肯定了行为结果,在N250和N400两个脑电成分上都发现了启动类型和目标类型交互作用有关的效应,当启动词和目标词共享词素同形同义时,同时引发了N250和N400的变化;当共享词素同形不同义时,时程分析时虽然也发现了N250的变化,但是N250的效应较小,小于同形同义所引发的N250效应,持续时间也较短。实验结果说明,在词汇识别中歧义词素语义可以激活,并对目标词汇加工的早期加工阶段发挥作用。     

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).     

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.     

Exploring the contribution of the cerebral hemispheres to language comprehension deficits in adults with developmental language disorder

A divided visual field, priming paradigm was used to observe how adults who have a history of developmental language disorder (DLD) access lexically ambiguous words. The results show that sustained semantic access to subordinate word meanings (such as BANK-RIVER), which is seen in control subjects, is disrupted in the right cerebral hemisphere for this special population of readers. In the left hemisphere, only the most dominant meaning of the ambiguous word shows sustained priming in both controls and DLD participants. Therefore, for the DLD readers the subordinate meanings of words are not primed in either hemisphere and, thus, may not be available during online processing and integration of discourse. This right hemisphere lexical access deficit might contribute to the language comprehension difficulties exhibited by adult readers with a history of DLD.     

不同认知方式个体抑制歧义词不适当意义的机制

本试验采用固定速的移动窗口范式和意义适合性判断任务,考察场依存、场独立个体抑制句子中歧义词不适当意义的机制以及歧义词歧义消解的进程。结果表明：不同认知方式个体在抑制句子中歧义词不适当意义的时间进程上存在差异,与场依存者相比,场独立者能够较早地抑制歧义的干扰;同时,本研究证明歧义词的多个意义首先激活,然后与语境不一致的意义得到抑制,研究结果支持词汇歧义消解的多重通达模型。     

Influence of context on the activation and selection of ambiguous word senses

The activation of ambiguous word senses was investigated by measuring the amount of interference in naming the ink color of a word that was either related or unrelated to one of the meanings of a preceding ambiguous word. In agreement with previous results obtained using this procedure (Conrad, 1974), evidence was obtained that both meanings of the ambiguous words are activated even in the presence of biasing context. However, contrary to previous findings, the degree of activation of each word sense depended on its degree of compatibility with the context. These results are consistent with a language processing system in which all interpretations of an ambiguity are accessed and then processed until an accurate determination has been made of which interpretation best satisfies the syntactic and semantic constraints that govern it.     

Automatic access of the meanings of ambiguous words in context: Some limitations of knowledge-based processing

Five experiments are described on the processing of ambiguous words in sentences. Two classes of ambiguous words (noun-noun and noun-verb) and two types of context (priming and nonpriming) were investigated using a variable stimulus onset asynchrony (SOA) priming paradigm. Noun-noun ambiguities have two semantically unrelated readings that are nouns (e.g., PEN, ORGAN); noun-verb ambiguities have both noun and verb readings that are unrelated (e.g., TIRE, WATCH). Priming contexts contain a word highly semantically or associatively related to one meaning of the ambiguous word; nonpriming contexts favor one meaning of the word through other types of information (e.g., syntactic or pragmatic). In nonpriming contexts, subjects consistently access multiple meanings of words and select one reading within 200 msec. Lexical priming differentially affects the processing of subsequent noun-noun and noun-verb ambiguities, yielding selective access of meaning only in the former case. The results suggest that meaning access is an automatic process which is unaffected by knowledge-based (“top-down”) processing. Whether selective or multiple access of meaning is observed largely depends on the structure of the ambiguous word, not the nature of the context.     

Interpretive cues and ambiguity in generalized anxiety disorder

The current study investigated whether generalized anxiety disorder (GAD) individuals rely on antecedent information to interpret ambiguity and whether reliance on such preceding cues persists in the absence of potential threat. Twenty-six GAD and 23 nonanxious control college students performed a lexical decision task, using homographs (i.e. words with multiple meanings) as ambiguous primes. In half the trials, a homograph prime that possessed both threat-related, as well as neutral meanings was followed by a target word related to one of these two meanings. In addition, each ambiguous prime was immediately preceded by a series of four antecedent words that were either: (a) associated with the threatening meaning of the prime; (b) associated with the neutral meaning of the prime; or (c) unrelated to either meaning of the homograph, as well as the target. Homographs for which both meanings were neutral in valence comprised the other half of the trials. Effect size statistics suggest that GAD participants utilized the antecedent words to interpret the homograph primes with threat-related meanings, unlike their nonanxious counterparts (p<0.06). When both meanings of the homograph prime were neutral in valence, the GAD group appeared deficient in the use of preceding information to interpret the ambiguous prime.     

Multiple semantic encoding of homophones and homographs in contexts biasing dominant or subordinate meanings

The resolution of lexical ambiguity was studied in two experiments. While subsequent selection would appear to limit longer term storage to one meaning of an ambiguous word, multiple initial encoding of homophones and homographs was indicated by the intrusion of their alternative meanings across trials in a Brown-Peterson paradigm. In Experiment 1 subjects heard four words and then engaged in a 10osec distractor task. Written recall was then demanded. On context trials a homophone with two distinct alternative meanings was presented with other words biasing either a dominant or subordinate meaning, for example, look, stare,peer, glance. On the next trial words related to an alternative meaning were presented, for example, dock, wharf, quay, jetty. Intrusions of the graphic forms of alternative meanings le.g.,PIER) into critical trial recall occurred whether the dominant or subordinate meaning of the homophone had been biased by context. Experiment 2 employed visual presentation of homographs, for example, GOLD, IRON,LEAD, and oral recall, but was logically similar to Experiment 1. Intrusions of the alternative codings of homographs across trials again occurred, for example, GUIDE, DIRECT,lead, regardless of the meaning originally biased by context.     

汉语老年读者的多词单元加工：来自眼动研究的证据

选取由两个双字词组成的多词组合（单词组合、模糊词组合、双词组合）,比较老年人和青年人对多词单元的加工情况。结果发现,相比于其他两类组合,所有被试在单词组合上的注视时间更短,第一遍注视次数更少,成分词上的注视时间更短,跳读率更高,表现出多词单元的加工优势,而且这一加工优势不存在显著的年龄差异。结果表明,汉语老年读者同样将多词单元作为整体进行加工。     

Turning an advantage into a disadvantage: Ambiguity effects in lexical decision versus reading tasks

When performing a lexical decision task, participants can correctly categorize letter strings as words faster if they have multiple meanings (i.e., ambiguous words) than if they have one meaning (i.e., unambiguous words). In contrast, when reading connected text, participants tend to fixate longer on ambiguous words than on unambiguous words. Why are ambiguous words at an advantage in one word recognition task, and at a disadvantage in another? These disparate results can be reconciled if it is assumed that ambiguous words are relatively fast to reach a semantic-blend state sufficient for supporting lexical decisions, but then slow to escape the blend when the task requires a specific meaning be retrieved. We report several experiments that support this possibility.     

Hemispheric contributions to lexical ambiguity resolution in a discourse context: evidence from individuals with unilateral left and right hemisphere lesions

In the present study, a cross-modal semantic priming task was used to investigate the ability of left-hemisphere-damaged (LHD) nonfluent aphasic, right-hemisphere-damaged (RHD) and non-brain-damaged (NBD) control subjects to use a discourse context to resolve lexically ambiguous words. Subjects first heard four-sentence discourse passages ending in ambiguous words and after an inter-stimulus interval (ISI) of either 0 or 750 ms, made lexical decisions on first- or second-meaning related visual targets. NBD control subjects, at the 0 ms ISI, only activated contextually appropriate meanings, though significant effects, as a group, were only seen in second-meaning biased contexts. Surprisingly, at the 750 ms ISI, these subjects activated both appropriate and inappropriate meanings in first-meaning biased contexts. With respect to the LHD nonfluent aphasic patients, the majority activated first meanings regardless of context at the 0 ms ISI, though effects for the group were not significant. At the 750 ms ISI, these patients again activated first meanings regardless of context, with significant effects for the group only seen in first-meaning biased contexts. With regard to the RHD patients, the majority activated second meanings regardless of context at the 0 ms ISI and first meanings regardless of context at the 750 ms ISI, though, as a group, the effects were not significant. In light of our previous findings (Grindrod & Baum, 2003, submitted), the present data are interpreted as supporting the notion that damage to the left hemisphere disrupts either lexical access processes or the time course of lexical activation, whereas damage to the right hemisphere impairs the use of context and leads to activation of ambiguous word meanings based on meaning frequency.     

Lexical ambiguity, semantic context, and visual word recognition.

Some alternative hypotheses about the recognition of ambiguous words are considered. According to the selective-access hypothesis, prior semantic context biases people to access one meaning of an ambiguous word rather than another in lexical memory during recognition. In contrast, the nonselectiveaccess hypothesis states that all meanings of the word are accessed regardless of the context. We tested certain versions of these hypotheses by having students decide whether selected strings of letters were English words. The stimuli included test sequnces of three words in which the second word had two distinct possible meanings, whereas the first and third words were related to these meanings in various ways. When the first and third words were related to the same meaning of the ambiguous second word (e.g., SAVE-BANK-MONEY), the reaction time to recognize the third word decreased. But when the first and third words were related to different meanings of the second word (e.g., RIVER-BANK-MONEY), the reaction time for the third word was not reliably different from a control sequence with unrelated words. These and other data favor the selective-access hypothesis. Selective access to lexical memory is discussed in relation to models of word recognition.     

Processing homonymy and polysemy: effects of sentential context and time-course following unilateral brain damage

The present study investigated the abilities of left-hemisphere-damaged (LHD) non-fluent aphasic, right-hemisphere-damaged (RHD), and normal control individuals to access, in sentential biasing contexts, the multiple meanings of three types of ambiguous words, namely homonyms (e.g., "punch"), metonymies (e.g., "rabbit"), and metaphors (e.g., "star"). Furthermore, the predictions of the "suppression deficit" and "coarse semantic coding" hypotheses, which have been proposed to account for RH language function/dysfunction, were tested. Using an auditory semantic priming paradigm, ambiguous words were incorporated in dominant- or subordinate-biasing sentence-primes followed after a short (100 ms) or long (1,000 ms) interstimulus interval (ISI) by dominant-meaning-related, subordinate-meaning-related or unrelated target words. For all three types of ambiguous words, both the effects of context and ISI were obvious in the performance of normal control subjects, who showed multiple meaning activation at the short ISI, but eventually, at the long ISI, contextually appropriate meaning selection. Largely similar performance was exhibited by the LHD non-fluent aphasic patients as well. In contrast, RHD patients showed limited effects of context, and no effects of the time-course of processing. In addition, although homonymous and metonymous words showed similar patterns of activation (i.e., both meanings were activated at both ISIs), RHD patients had difficulties activating the subordinate meanings of metaphors, suggesting a selective problem with figurative meanings. Although the present findings do not provide strong support for either the "coarse semantic coding" or the "suppression deficit" hypotheses, they are viewed as being more consistent with the latter, according to which RH damage leads to deficits suppressing alternative meanings of ambiguous words that become incompatible with the context.     

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.