Semantic facilitation and lexical access during sentence processing: An investigation of individual differences

An earlier experiment (Blank & Foss, 1978) showed that the time required to access the object noun of a sentence was shortened if the noun was preceded by a semantically related verb or adjective. When both the verb and the adjective were semantically related to the noun, the amount of facilitation of lexical access was additive. However, additivity appeared to break down for subjects who did poorly on the comprehension test administered in that experiment, suggesting that the activation function among related lexical items was different for good and poor comprehenders. Such a finding would have implications for theories of lexical facilitation, especially the two-factor theories such as the one proposed by Posner and Snyder (1975). The present experiment again measured access time for the object noun of a sentence when it was preceded by an unrelated or a related verb or adjective (four sentence types). Two groups of college subjects were tested, relatively good (N = 63) and relatively poor (N = 42) comprehenders. The difference in the time taken to retrieve the object noun was ascertained by measuring reaction time to respond to the initial phoneme of the next word in the sentence (phoneme monitoring technique). Reaction times were shorter when the noun was preceded by a semantically related word; the effects of two sources of related context (verb and adjective) appeared to be additive forboth groups of subjects. These results were discussed within the context of two-factor theories of lexical activation and within the context of Morton’s (1969) logogen model.     

Semantic context influences memory for verbs more than memory for nouns

Three experiments revealed that memory for verbs is more dependent on semantic context than is memory for nouns. The participants in Experiment 1 were asked to remember either nouns or verbs from intransitive sentences. A recognition test included verbatim sentences, sentences with an old noun and a new verb, sentences with an old verb and a new noun, and entirely new sentences. Memory for verbs was significantly better when the verb was presented with the same noun at encoding and at retrieval. This contextual effect was much smaller for nouns. Experiments 2 and 3 replicated this effect and provided evidence that context effects reflect facilitation from bringing to mind the same meaning of a verb at encoding and at retrieval. Memory for verbs may be more dependent on semantic context because the meanings of verbs are more variable across semantic contexts than are the meanings of nouns.     

Determining inhibition: Individual differences in the 'lexicon context' trade-off during lexical ambiguity resolution in working memory

The current experiment assessed the relation between inhibitory mechanisms underlying language processing in working memory (WM) and the influence of a postulated internal cognitive trade-off between lexicon and context factors driving inhibition in sentence processing. Participants with high and low WM span (Daneman & Carpenter, 1980) were presented with sentences that began with an ambiguous noun (being both homographic and homophonic). A cue towards the relevant meaning of the ambiguous word was presented three words later by another noun. Immediately after the cue, a verb was presented that finally disambiguated the ambiguous noun. In half of the cases, the final disambiguation was congruent with the disambiguation cue. In the other half, subjects had to realize that it was not the cued but the other meaning, which turned out to be relevant in the actual sentence. This experimental paradigm was identical to the one used in Gunter et al. (2003). In contrast to the original experiment, the filler items in the present study were unambiguous. Both groups showed a smaller N400 component for the cue related to the dominant as compared to the subordinate meaning, suggesting that the dominant meaning was more active in WM than the subordinate one. In the original experiment, only the high-span subjects manifested this effect. Thus, a change in the global experimental setting changed the use of WM-related inhibitory processes. Data also suggest that, as a default strategy, the lexicon-context trade-off of high-span subjects relies more on lexicon information than does that of low-span subjects.     

Semantic facilitation and lexical access during sentence processing

An experiment was conducted testing predictions derived from context-dependent and context-independent models of lexical access. Four types of unambiguous test sentences were constructed. The direct object of each test sentence was preceded by a verb that was either semantically related or unrelated to it, and by an adjective that was semantically related or unrelated. Context-dependent models predict that the speed with which the object noun is retrieved from the mental lexicon will be faster when the verb and/or the adjective is semantically related; context-independent models predict no such facilitation. Forty-four subjects each heard 32 test sentences and were asked to monitor within the sentence for a word-initial target phoneme. The target phoneme occurred on the word following the object noun. Reaction times to detect the targets were obtained. According to context-dependent models, these times should be shorter when related words precede the object noun, and that is what was found. It was also observed that the facilitation effects due to the related verbs and adjectives were additive. Implications of these results were discussed.     

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.     

Effect of Representational Distance Between Meanings on Recognition of Ambiguous Spoken Words

Previous research indicates that mental representations of word meanings are distributed along both semantic and syntactic dimensions such that nouns and verbs are relatively distinct from one another. Two experiments examined the effect of representational distance between meanings on recognition of ambiguous spoken words by comparing recognition of unambiguous words, noun–verb homonyms, and noun–noun homonyms. In Experiment 1, auditory lexical decision was fastest for unambiguous words, slower for noun–verb homonyms, and slowest for noun–noun homonyms. In Experiment 2, response times for matching spoken words to pictures followed the same pattern and eye fixation time courses revealed converging, gradual time course differences between conditions. These results indicate greater competition between meanings of ambiguous words when the meanings are from the same grammatical class (noun–noun homonyms) than when they are from different grammatical classes (noun–verb homonyms).     

Structure and limited capacity in verbal working memory: a study with event-related potentials

In order to test recent claims about the structure of verbal working memory, two ERP experiments with Dutch speaking participants were carried out. We compared the ERP effects of syntactic and semantic mid-sentence anomalies in subject and object relative sentences. In Experiment 1, the participants made acceptability judgments, while in Experiment 2 they read for comprehension. Syntactic anomalies concerned subject-verb disagreement, while semantic anomalies were related to implausible events (e.g., *The cat that fled from the mice ran through the room). Semantic anomalies did not elicit an N400 effect. The semantic as well as syntactic anomalies elicited P600 effects, with similar centro-parietal scalp distributions. For both kinds of anomaly, the P600 effects were modulated by syntactic complexity: they were either relatively small (Experiment 1) or absent (Experiment 2) in object relative sentences. Taken together, our results suggest that: (a) verbal working memory is a limited capacity system; (b) it is not subdivided into an interpretative and a post-interpretative component (); (c) the P600 can reflect the presence of a semantic bias in syntactically unambiguous sentences; (d) the P600 is related to language monitoring: its function is to check upon the veridicality of an unexpected (linguistic) event; (e) if such a check is made, there is no integration of the event and hence no N400 effect.     

Working memory and planning during sentence production

Speakers retrieve conceptual, syntactic and lexical information in advance of articulation during sentence production. What type of working memory (WM) store is used to hold the planned information before speaking? To address this question, we measured onset latencies when subjects produced sentences that began with either a complex or a simple initial noun phrase, while holding semantic, phonological or spatial information in WM. Although we found that subjects had longer onset latencies for sentences beginning with a complex noun phrase, showing a phrasal scope of planning, the magnitude of this complexity effect was not affected by any type of WM load. However, subjects made more syntactic errors (but not lexical errors) for sentences beginning with a complex noun phrase, suggesting that advance planning for these phrases occurs at a syntactic rather than lexical–semantic level, which may account for the lack of effect with various types of WM load in the current study.     

Using puns to study contextual influences on lexical ambiguity resolution: Evidence from eye movements

Participants’ eye movements were monitored while they read sentences containing biased homographs in either a single-meaning context condition that instantiated the subordinate meaning of the homograph without ruling out the dominant meaning (e.g., “The man with a toothache had a crown made by the best dentist in town”) or a dual-meaning pun context condition that supported both the subordinate and dominant meanings (e.g., “The king with a toothache had a crown made by the best dentist in town”). In both of these conditions, the homographs were followed by disambiguating material that supported the subordinate meaning and ruled out the dominant meaning. Fixation times on the homograph were longer in the single-meaning condition than in the dual-meaning condition, whereas the reverse pattern was demonstrated for fixation times on the disambiguating region; these effects were observed as early as first-fixation duration. The findings strongly support the reordered access model of lexical ambiguity resolution.     

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.     

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.     

Preliminary evidence for impaired rapid verb generation in schizophrenia

It has been hypothesized that nouns and verbs are processed within relatively separable semantic memory networks. Although abnormal semantic processing is a common feature of schizophrenia-spectrum disorders, no prior studies have specifically examined the comparability of noun and verb generation deficits in schizophrenia. In the current study, verb (action), noun (animal), and letter (f) fluency performance was evaluated in 22 inpatients with schizophrenia and 27 healthy comparison subjects. On average, individuals with schizophrenia performed approximately one standard deviation below the healthy comparison subjects on action, animal, and letter fluency. Action fluency-but not letter or animal fluency-was moderately correlated with tests of working memory, response inhibition, semantic memory, and cognitive flexibility. Findings suggest that verb- and noun-based fluency deficits are of comparable severity in schizophrenia, but that the impairment in verb generation may be driven by different underlying cognitive mechanisms. Further, hypothesis-driven research on the nature and extent of verb network disruption in schizophrenia appears warranted.     

汉语句子可继续性对句子理解加工的即时影响

通过操纵动词与后接词的关系,来产生搭配异常并控制句子的可继续性,研究汉语词汇信息在句子加工中的即时作用。实验一利用跨通道技术,发现动一名词搭配异常对目标名词的加工有即时影响,形容词条件下可继续性对目标形容词的加工有即时影响;实验二采用眼动技术,发现名词条件和形容词条件下可继续性均有显著的即时影响。结果显示,语义等多种词汇信息被通达后立即共同参与了汉语句子加工。     

汉语名词、动词和动名兼类词语义加工的偏侧化现象——来自ERP的研究

将ERP技术和半视野技术相结合,采用词汇判断任务,对汉语名词、动词和动名兼类词在左脑和右脑中的加工机制进行了考察。实验结果显示,名词和动词的N400仅在左视野/右脑存在差异,名词和动词的N400在左视野/右脑和右视野/左脑中都比偏（动）和偏（名）更负。不同词类的LPC在右视野/左脑中没有显著差异;偏（名）和偏（动）的LPC在左视野/右脑中比名词和动词更正。实验结果表明,在没有语境条件下,汉语名词和动词的差异主要在具体性上,动名兼类词体现出不同于名词、动词的加工机制。     

The processing of homophonic homographs during reading: Evidence from eye movement studies

Research on the processing of homophonic homographs during reading is reviewed. The primary dependent variable considered was fixation time on target homographs. Both the characteristics of the homograph (whether there are two equally likely meanings or one dominant meaning) and the characteristics of the preceding context (whether it is neutral or contains disambiguating information) were varied. When the preceding context was neutral, readers fixated longer on balanced homographs (homographs having two equally likely meanings) than on control words matched on frequency and length, but didn't look any longer at biased homographs (homographs having a highly dominant meaning) than matched control words. However, when the preceding context disambiguated toward the subordinate meaning, readers fixated longer on a biased homograph than a matched control word (the subordinate bias effect). Attempts to eliminate the subordinate bias effect are described and the implications of our research for models of lexical ambiguity resolution are discussed.Preparation of this paper was supported by grant DBS-9121375 from the National Science Foundation. We wish to thank our colleagues Sara Sereno and Chuck Clifton for their helpful comments on earlier drafts of this paper.     

The Mechanism Underlying Backward Priming in a Lexical Decision Task: Spreading Activation versus Semantic Matching

Koriat (1981) demonstrated that an association from the target to a preceding prime, in the absence of an association from the prime to the target, facilitates lexical decision and referred to this effect as 'backward priming'. Backward priming is of relevance, because it can provide information about the mechanism underlying semantic priming effects. Following Neely (1991), we distinguish three mechanisms of priming: spreading activation, expectancy, and semantic matching/ integration. The goal was to determine which of these mechanisms causes backward priming, by assessing effects of backward priming on a language-relevant ERP component, the N400, and reaction time (R T). Based on previous work, we propose that the N400 priming effect reflects expectancy and semantic matching/ integration, but in contrast with R T does not reflect spreading activation. Experiment 1 shows a backward priming effect that is qualitatively similar for the N400 and R T in a lexical decision task. This effect was not modulated by an ISI manipulation. Experiment 2 clarifies that the N400 backward priming effect reflects genuine changes in N400 amplitude and cannot be ascribed to other factors. We will argue that these backward priming effects cannot be due to expectancy but are best accounted for in terms of semantic matching/ integration.     

On the existence of semantic working memory: evidence for direct semantic maintenance

Despite widespread acknowledgment of the importance of online semantic maintenance, there has been astonishingly little work that clearly establishes this construct. We review the extant work relevant to short-term retention of meaning and show that, although consistent with semantic working memory, most data can be accommodated in other ways. Using a new concurrent probe paradigm, we then report experiments that implicate a semantic maintenance capacity that is independent of phonological or visual maintenance that may build on a mechanism of direct semantic maintenance. Experiments 1 through 5 established that while subjects maintain the meaning of a word, a novel delay-period marker of semantic retention, the semantic relatedness effect, is observed on a concurrent lexical decision task. The semantic relatedness effect refers to slowed response times when subjects make a lexical decision to a probe that is associatively related to the idea they are maintaining, compared to when the probe is unrelated. The semantic relatedness effect occurred for semantic but not for phonological or visual word-form maintenance, dissipated quickly after maintenance ends, and survived concurrent articulatory suppression. The effect disappeared when subjects performed our immediate memory task with a long-term memory strategy rather than with active maintenance. Experiment 6 demonstrated a parallel phonological relatedness effect that occurs for phonological but not semantic maintenance, establishing a full double dissociation between the effects of semantic and phonological maintenance. These findings support a distinct semantic maintenance capacity and provide a behavioral marker through which semantic working memory can be studied.     

Competition in lexical processing of Italian noun/verb homographs

The study investigates the lexical representation of Italian noun/verb homographs, introducing a factor which has been analysed in production studies: the specific-word frequency (SWF). The SWF parameter allows to understand whether the grammatical class information is specified within the lexical knowledge or it is selected during post-lexical stages. We ran six lexical decision tasks employing the priming paradigm and a grammatical decision task to investigate the lexical representation of noun/verb homographs. In addition, we sought to determine the role played by the frequency of representations and the temporal activation of the grammatical class information. Our findings support the claim that these forms have independent representations for each syntactic role they can play. We interpreted these findings in the light of what we call the “Nominal Dominance” effect, which affects the lexical access of noun/verb homographs. We also discuss the relation between nominal dominance and lexical frequency.     

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.     

Typicality effects in picture‐word interference paradigm: An evaluation of the response exclusion hypothesis

The response exclusion hypothesis suggests that the polarity of semantic effects in the picture‐word interference paradigm is determined by the response‐relevant criteria. Semantic interference effects would be observed when semantically related distractor words satisfy the response‐relevant criteria; otherwise, semantic facilitation effects should be found. The purpose of this study was to further evaluate the response exclusion hypothesis by exploring the typicality effects in pictures naming. In two experiments, pictures of objects were named either in the context of verb distractor words with different typicality of passive functions or in the context of adjective distractor words with different typicality of characteristics. Facilitation effects were observed in context of typical verbs and adjectives, while interference effects were observed in the context of atypical verbs and adjectives. Given that neither typical nor atypical distractor words satisfy the response‐relevant criteria to produce noun, these findings are problematic for the response exclusion hypothesis. Role of syntagmatic relationships in lexical retrieval was invoked to explain present findings.