Lexical Ambiguity Resolution Research Articles

Lexical Ambiguity Resolution Using Discourse Contexts in Persons With and Without Aphasia.

The purpose of this study was to investigate the ability of persons with aphasia (PWA) to resolve different types of ambiguous words (homophones, metaphors, and metonyms) in discourse contexts. Six PWA and 10 controls listened to short discourses that biased either the dominant (more frequent) or subordinate (less frequent) version of an ambiguous word as well as nonsense (filler) discourses. Participants then indicated whether or not the final sentence, which contained the ambiguity, made sense in the discourse. Data for both accuracy and reaction time were collected. There was no significant Group × Word Type × Frequency interaction in the reaction time data. In the accuracy analysis, there was a significant Group × Frequency × Word Type interaction, which appeared to be driven by the PWA's relative accuracy with subordinate homophones and relative inaccuracy with subordinate metaphors. These results suggest that PWA were able to use discourse contexts to resolve subordinate versions of literal ambiguous words but have difficulty resolving metaphoric ambiguous words. Further investigations should be done to clarify how much context PWA require to successfully resolve lexical ambiguities.

Tracking competition and cognitive control during language comprehension with multi-voxel pattern analysis

To successfully comprehend a sentence that contains a homonym, readers must select the ambiguous word’s context-appropriate meaning. The outcome of this process is influenced both by top-down contextual support and bottom-up, word-specific characteristics. We examined how these factors jointly affect the neural signatures of lexical ambiguity resolution. We measured the similarity between multi-voxel patterns evoked by the same homonym in two distinct linguistic contexts: once after subjects read sentences that biased interpretation toward each homonym’s most frequent, dominant meaning, and again after interpretation was biased toward a weaker, subordinate meaning. We predicted that, following a subordinate-biasing context, the dominant yet inappropriate meaning would nevertheless compete for activation, manifesting in increased similarity between the neural patterns evoked by the two word meanings. In left anterior temporal lobe (ATL), degree of within-word pattern similarity was positively predicted by the association strength of each homonym’s dominant meaning. Further, within-word pattern similarity in left ATL was negatively predicted by item-specific responses in a region of left ventrolateral prefrontal cortex (VLPFC) sensitive to semantic conflict. These findings have implications for psycholinguistic models of lexical ambiguity resolution, and for the role of left VLPFC function during this process. Moreover, these findings demonstrate the utility of item-level, similarity-based analyses of fMRI data for our understanding of competition between co-activated word meanings during language comprehension.

Do resource constraints affect lexical processing? Evidence from eye movements.

Human language is massively ambiguous, yet we are generally able to identify the intended meanings of the sentences we hear and read quickly and accurately. How we manage and resolve ambiguity incrementally during real-time language comprehension given our cognitive resources and constraints is a major question in human cognition. Previous research investigating resource constraints on lexical ambiguity resolution has yielded conflicting results. Here we present results from two experiments in which we recorded eye movements to test for evidence of resource constraints during lexical ambiguity resolution. We embedded moderately biased homographs in sentences with neutral prior context and either long or short regions of text before disambiguation to the dominant or subordinate interpretation. The length of intervening material had no effect on ease of disambiguation. Instead, we found only a main effect of meaning at disambiguation, such that disambiguating to the subordinate meaning of the homograph was more difficult-results consistent with the reordered access model and contemporary probabilistic models, but inconsistent with the capacity-constrained model.

Understanding underspecification: A comparison of two computational implementations.

Swets et al. (2008. Underspecification of syntactic ambiguities: Evidence from self-paced reading. Memory and Cognition, 36(1), 201–216) presented evidence that the so-called ambiguity advantage [Traxler et al. (1998). Adjunct attachment is not a form of lexical ambiguity resolution. Journal of Memory and Language, 39(4), 558–592], which has been explained in terms of the Unrestricted Race Model, can equally well be explained by assuming underspecification in ambiguous conditions driven by task-demands. Specifically, if comprehension questions require that ambiguities be resolved, the parser tends to make an attachment: when questions are about superficial aspects of the target sentence, readers tend to pursue an underspecification strategy. It is reasonable to assume that individual differences in strategy will play a significant role in the application of such strategies, so that studying average behaviour may not be informative. In order to study the predictions of the good-enough processing theory, we implemented two versions of underspecification: the partial specification model (PSM), which is an implementation of the Swets et al. proposal, and a more parsimonious version, the non-specification model (NSM). We evaluate the relative fit of these two kinds of underspecification to Swets et al.’s data; as a baseline, we also fitted three models that assume no underspecification. We find that a model without underspecification provides a somewhat better fit than both underspecification models, while the NSM model provides a better fit than the PSM. We interpret the results as lack of unambiguous evidence in favour of underspecification; however, given that there is considerable existing evidence for good-enough processing in the literature, it is reasonable to assume that some underspecification might occur. Under this assumption, the results can be interpreted as tentative evidence for NSM over PSM. More generally, our work provides a method for choosing between models of real-time processes in sentence comprehension that make qualitative predictions about the relationship between several dependent variables. We believe that sentence processing research will greatly benefit from a wider use of such methods.

A Behavioral and Electrophysiological Investigation of the Effect of Bilingualism on Lexical Ambiguity Resolution in Young Adults.

Previous research suggests that bilinguals demonstrate superior cognitive control processes than monolinguals. The goal of the current investigation was to examine whether this “bilingual advantage” is observed in a language processing task that requires inhibition, i.e., lexical ambiguity processing. Monolingual and bilingual participants read sentences that biased the reading of a terminal homonym toward the subordinate or dominant reading (e.g., The doctor asked her to step onto the scale.). A relatedness judgment was made on target words that were related to the contextually appropriate (e.g., balance) or inappropriate meaning (e.g., skin), or unrelated to either meaning (e.g., shoe) while electrophysiological recording took place. The results revealed subtle processing differences between monolinguals and bilinguals that were evident in electrophysiological measures, but not in behavioral measures. These findings suggest that monolinguals rely on context to access the contextually appropriate meaning of a homonym to a greater extent than bilinguals, while bilinguals demonstrate simultaneous activation of both meanings.

Exhaustive semantic activation for reading ambiguous verbs in Chinese sentences

Studies of lexical ambiguity resolution in sentential contexts have not sufficiently considered the relatedness among an ambiguous word’s meanings as a predicting factor for semantic activation. To better understand the relation between lexical access and discourse processing and the effect of semantic relatedness on lexical ambiguity resolution, a cross-modal lexical priming experiment focusing on Mandarin ambiguous verbs of varying degrees of semantic relatedness was conducted. The results indicated that both meanings of an ambiguous verb were activated regardless of contextual biases and the degrees of semantic relatedness between the associated meanings. Taken together with previous research, the present study suggests that the meanings of an ambiguous word (i.e., homophonic homographs, which share both phonological and orthographic representations) are co-activated exhaustively if they are syntactically licensed by the context. These results thus support the exhaustive semantic activation model of lexical ambiguity resolution and the syntax-first theory of sentence processing.

Noun/verb distinction in English stress homographs: an ERP study.

Sensitivity to speech rhythm, especially the pattern of stressed and unstressed syllables, is an important aspect of language acquisition and comprehension from infancy through adulthood. In English, a strong correlation exists between speech rhythm and grammatical class. This property is well illustrated by a particular group of noun/verb homographs that are spelled the same but are pronounced with a lexical stress on the first syllable when used as a noun or on the second syllable when used as a verb. The purpose of this study was to further examine the neural markers of speech rhythm and its role in word recognition. To this end, event-related brain potentials were recorded while participants listened to spoken sentences containing a stress homograph either in a noun or a verb position. The rhythmic structure of the stress homographs was manipulated so that they were pronounced with a stress pattern that either matched or mismatched their grammatical class. Results of cluster-based permutation tests on the event-related brain potentials revealed larger negativities over the centrofrontal scalp regions when the stress homographs were mispronounced, in line with previous studies on lexical ambiguity resolution. In addition, differences between rhythmically unexpected nouns and verbs could be seen as early as 200 ms, suggesting that listeners are sensitive to statistical properties of their language rhythm. Together, these results support the hypothesis that information about speech rhythm is rapidly integrated during speech perception and contributes to lexical retrieval.

Eye movements in reading and information processing: Keith Rayner’s 40 year legacy

Keith Rayner’s extraordinary scientific career revolutionized the field of reading research and had a major impact on almost all areas of cognitive psychology. In this article, we review some of his most significant contributions. We begin with Rayner’s research on eye movement control, including the development of paradigms for answering questions about the perceptual span and its relationship to attention, reading experience, and linguistic variables. From there we proceed to lexical processing, where we summarize Rayner’s work on effects of word frequency, length, predictability, and the resolution of lexical ambiguity. Next, we turn to syntactic and discourse processing, covering the well-known garden-path model of parsing and briefly reviewing studies of pronoun resolution and inferencing. The next section shifts from language to visual cognition and reviews research which makes use of eye movement techniques to investigate object and scene processing. Next, we summarize Rayner and colleagues’ approach to computational modeling, with a description of the E-Z Reader model linking attention and lexical processing to eye movement control. The final section discusses the issues Rayner and his colleagues were focused on most recently and considers how Rayner’s legacy will continue into the future.

The Influence of Syntactic Category and Semantic Constraints on Lexical Ambiguity Resolution: An Eye Movement Study of Processing Chinese Homographs

The purpose of the present study is twofold: (1) To examine whether the syntactic category constraint can determine the semantic resolution of Chinese syntactic category ambiguous words; and (2) to investigate whether the syntactic category of alternative meanings of Chinese homographs can influence the subordinate bias effect (SBE) during lexical ambiguity resolution. In the present study, four types of Chinese biased homographs (NN, VV, VN, and NV) were embedded into syntactically and semantically subordinate-biased sentences. Each homograph was assigned a frequency-matched unambiguous word as control, which could fit into the same sentence frame. Participants' eye movements were recorded as they read each sentence. In general, the results showed that in a subordinate-biased context, (1) the SBE for the four types of homograph was significant only in the second-pass reading on the post-target words and (2) numerically, the NV homographs revealed a larger effect size of SBE than VN homographs on both target and post-target words. Our findings support the constraint-satisfaction models, suggesting that the syntactic category constraint is not the only factor influencing the semantic resolution of syntactic category ambiguous words, which is opposed to the prediction of the syntax-first models.

Automatic Detection and Resolution of Lexical Ambiguity in Process Models

System-related engineering tasks are often conducted using process models. In this context, it is essential that these models do not contain structural or terminological inconsistencies. To this end, several automatic analysis techniques have been proposed to support quality assurance. While formal properties of control flow can be checked in an automated fashion, there is a lack of techniques addressing textual quality. More specifically, there is currently no technique available for handling the issue of lexical ambiguity caused by homonyms and synonyms. In this paper, we address this research gap and propose a technique that detects and resolves lexical ambiguities in process models. We evaluate the technique using three process model collections from practice varying in size, domain, and degree of standardization. The evaluation demonstrates that the technique significantly reduces the level of lexical ambiguity and that meaningful candidates are proposed for resolving ambiguity.

Reanalyzing the Complement Coercion Effect through a Generalized Lexical Semantics for Aspectual Verbs: Table 1

Aspectual verbs like begin , start and finish form a subset of the class of ‘coercion verbs’ implicated in the phenomenon of complement coercion. Such verbs have been assumed to select exclusively for eventive complements (e.g. John began/enjoyed reading the book/the meeting ). The standard view holds that the composition of an entity-denoting expression with any coercion verb obligatorily gives rise to a type-mismatch, which can only be resolved by ‘coercing’ the entity-denoting expression into an event-denoting expression. The experimental literature has presupposed such an event-selecting lexical semantics for all coercion verbs and interpreted processing and neurological phenomena as being reflexes of entity-to-event type-shifting. However, recent evidence shows that the complement coercion phenomenon is far from uniform and that aspectual verbs, in contrast to other coercion verbs, uniquely exhibit processing cost ( Katsika et al. 2012 ; Utt et al. 2013 ; Lai et al. 2014 ). This article provides a new lexical semantic analysis for aspectual verbs which leads to a hypothesis that not only captures the psycholinguistic evidence, but also makes new predictions. On this analysis, aspectual verbs lexically select for structured individuals—entities that can be construed as one-dimensional directed path structures ( Krifka 1998 ) in some ontological dimension. This analysis has wide empirical coverage: it accounts for the full range of complements that aspectual verbs legitimately combine with in their transitive uses, and it does so without appealing to any coercive entity-to-event type-shifting operations. Finally, the analysis allows for a simpler, conceptually grounded interpretation of the observed processing cost as resulting from exhaustive lexical retrieval (on the verb) and ambiguity resolution (on the complement).

Rapid Linguistic Ambiguity Resolution in Young Children with Autism Spectrum Disorder: Eye Tracking Evidence for the Limits of Weak Central Coherence.

Individuals with autism spectrum disorders (ASD) have often been reported to have difficulty integrating information into its broader context, which has motivated the Weak Central Coherence theory of ASD. In the linguistic domain, evidence for this difficulty comes from reports of impaired use of linguistic context to resolve ambiguous words. However, recent work has suggested that impaired use of linguistic context may not be characteristic of ASD, and is instead better explained by co-occurring language impairments. Here, we provide a strong test of these claims, using the visual world eye tracking paradigm to examine the online mechanisms by which children with autism resolve linguistic ambiguity. To address concerns about both language impairments and compensatory strategies, we used a sample whose verbal skills were strong and whose average age (7; 6) was lower than previous work on lexical ambiguity resolution in ASD. Participants (40 with autism and 40 controls) heard sentences with ambiguous words in contexts that either strongly supported one reading or were consistent with both (John fed/saw the bat). We measured activation of the unintended meaning through implicit semantic priming of an associate (looks to a depicted baseball glove). Contrary to the predictions of weak central coherence, children with ASD, like controls, quickly used context to resolve ambiguity, selecting appropriate meanings within a second. We discuss how these results constrain the generality of weak central coherence.

Bilingual access of homonym meanings: Individual differences in bilingual access of homonym meanings

The goal of the present study was to identify the cognitive processes that underlie lexical ambiguity resolution in a second language (L2). We examined which cognitive factors predict the efficiency in accessing subordinate meanings of L2 homonyms in a sample of highly-proficient, Spanish–English bilinguals. The predictive ability of individual differences in (1) homonym processing in the L1, (2) working memory capacity and (3) sensitivity to cross-language form overlap were examined. In two experiments, participants were presented with cognate and noncognate homonyms as either a prime in a lexical decision task (Experiment 1) or embedded in a sentence (Experiment 2). In both experiments speed and accuracy in accessing subordinate meanings in the L1 was the strongest predictor of speed and accuracy in accessing subordinate meanings in the L2. Sensitivity to cross-language form overlap predicted performance in lexical decision while working memory capacity predicted processing in sentence comprehension.

The processing of lexical ambiguity in healthy ageing and Parkinson׳s disease: Role of cortico-subcortical networks

Previous neuroimaging studies showed that correct resolution of lexical ambiguity relies on the integrity of prefrontal and inferior parietal cortices. Whereas prefrontal brain areas were associated with executive control over semantic selection, inferior parietal areas were linked with access to modality-independent representations of semantic memory. Yet insufficiently understood is the contribution of subcortical structures in ambiguity processing. Patients with disturbed basal ganglia function such as Parkinson׳s disease (PD) showed development of discourse comprehension deficits evoked by lexical ambiguity. To further investigate the engagement of cortico-subcortical networks functional Magnetic Resonance Imaging (fMRI) was monitored during ambiguity resolution in eight early PD patients without dementia and 14 age- and education-matched controls. Participants were required to relate meanings to a lexically ambiguous target (homonym). Each stimulus consisted of two words arranged on top of a screen, which had to be attributed to a homonym at the bottom. Brain activity was found in bilateral inferior parietal (BA 39), right middle temporal (BA 21/22), left middle frontal (BA 10) and bilateral inferior frontal areas (BA 45/46). Extent and amplitude of activity in the angular gyrus changed depending on semantic association strength that varied between conditions. Less activity in the left caudate was associated with semantic integration deficits in PD. The results of the present study suggest a relationship between subtle language deficits and early stages of basal ganglia dysfunction. Uncovering impairments in ambiguity resolution may be of future use in the neuropsychological assessment of non-motor deficits in PD.

Lexical interference effects in sentence processing: evidence from the visual world paradigm and self-organizing models.

Psycholinguistic research spanning a number of decades has produced diverging results with regard to the nature of constraint integration in online sentence processing. For example, evidence that language users anticipatorily fixate likely upcoming referents in advance of evidence in the speech signal supports rapid context integration. By contrast, evidence that language users activate representations that conflict with contextual constraints, or only indirectly satisfy them, supports nonintegration or late integration. Here we report on a self-organizing neural network framework that addresses 1 aspect of constraint integration: the integration of incoming lexical information (i.e., an incoming word) with sentence context information (i.e., from preceding words in an unfolding utterance). In 2 simulations, we show that the framework predicts both classic results concerned with lexical ambiguity resolution (Swinney, 1979; Tanenhaus, Leiman, & Seidenberg, 1979), which suggest late context integration, and results demonstrating anticipatory eye movements (e.g., Altmann & Kamide, 1999), which support rapid context integration. We also report 2 experiments using the visual world paradigm that confirm a new prediction of the framework. Listeners heard sentences like "The boy will eat the white …" while viewing visual displays with objects like a white cake (i.e., a predictable direct object of "eat"), white car (i.e., an object not predicted by "eat," but consistent with "white"), and distractors. In line with our simulation predictions, we found that while listeners fixated white cake most, they also fixated white car more than unrelated distractors in this highly constraining sentence (and visual) context.

Right semantic modulation of early MEG components during ambiguity resolution

The time-line of lexical ambiguity resolution in bilateral neuronal networks was investigated using magnetoencephalography (MEG) in a semantic decision task. Dominant and subordinate associations of ambiguous words are considered to be processed in the left and right hemispheres, respectively. In the experiment, ambiguous words were followed by dominant or subordinate associations (manipulated between blocks) or by unrelated target words, and participants (N=25) decided whether the words in each pair were related or not. Subordinate meaning blocks elicited greater changes in the magnetic fields relative to dominant ones over the right, but not the left hemisphere (LH) at 150–235ms from target onset, a time window corresponding to the M/N170 M/EEG component. Beamforming analysis localized the differential right hemisphere (RH) activity at the perisylvian area, including the homologue regions of Broca's and Wernicke's. At a later stage (235–390ms) there was no significant difference between the two meaning conditions. We suggest that the RH language regions assist the LH in integrating subordinate disambiguating clues to preceding context during the M170 time window.

Cross-age comparisons reveal multiple strategies for lexical ambiguity resolution during natural reading.

Eye tracking was used to investigate how younger and older (60 or more years) adults use syntactic and semantic information to disambiguate noun/verb (NV) homographs (e.g., park). In event-related potential (ERP) work using the same materials, Lee and Federmeier (2009, 2011) found that young adults elicited a sustained frontal negativity to NV homographs when only syntactic cues were available (i.e., in syntactic prose); this effect was eliminated by semantic constraints. The negativity was only present in older adults with high verbal fluency. The current study shows parallel findings: Young adults exhibit inflated first fixation durations to NV homographs in syntactic prose, but not semantically congruent sentences. This effect is absent in older adults as a group. Verbal fluency modulates the effect in both age groups: High fluency is associated with larger first fixation effects in syntactic prose. Older, but not younger, adults also show significantly increased rereading of the NV homographs in syntactic prose. Verbal fluency modulates this effect as well: High fluency is associated with a reduced tendency to reread, regardless of age. This relationship suggests a trade-off between initial and downstream processing costs for ambiguity during natural reading. Together the eye-tracking and ERP data suggest that effortful meaning selection recruits mechanisms important for suppressing contextually inappropriate meanings, which also slow eye movements. Efficacy of frontotemporal circuitry, as captured by verbal fluency, predicts the success of engaging these mechanisms in both young and older adults. Failure to recruit these processes requires compensatory rereading or leads to comprehension failures (Lee & Federmeier, 2012).

Lexical co-occurrence and ambiguity resolution

This study investigates the possible influence of lexical co-occurrence on lexical ambiguity resolution in sentence contexts. Lexical co-occurrence refers to similarity between the co-occurrence vectors of words, such that if two words have similar profiles of occurrence with other words, they are said to have a strong co-occurrence relationship. The present study examines whether lexical ambiguity resolution can be biased by the prior presentation of a word that shares a strong co-occurrence relationship with an ambiguous word under one of its meanings, despite the absence of plausibility support. Two “maze” word-by-word reading experiments examined highly implausible/anomalous sentences with balanced homographs. In sentences in which the ambiguous word (e.g., bat) was preceded by a biasing word with which it shares a strong co-occurrence relationship (e.g., umpire), (1) response times (RTs) to the ambiguous word were facilitated, and (2) garden-path effects were found when subsequent (disambiguating) information was incongruent with the biased meaning (e.g., The umpire tried to swallow the bat but its wings got stuck in his throat). Additional experiments showed that these biasing effects resist explanation in terms of a passive process of spreading activation. Furthermore, an eye-tracking experiment revealed a pattern of results comparable to that of the maze task experiments, indicating that these effects are not artefacts of the maze procedure. These results are taken to support a heuristic for lexical ambiguity resolution that is driven by relatively low-level intralexical connections based on lexical co-occurrence.

Lexical Ambiguity Resolution in Non-fluent and Fluent Aphasia: Eye-tracking Data

Lexical Ambiguity Resolution in Non-fluent and Fluent Aphasia: Eye-tracking Data

Effects of left and right hemisphere damage on sensitivity to global context during lexical ambiguity resolution

Background: A great deal of research suggests that both the left hemisphere (LH) and right hemisphere (RH) contribute to the resolution of lexically ambiguous words. If this is indeed the case, then patients with left (LHD) or right hemisphere brain damage (RHD) should exhibit deficits in ambiguity resolution. Although several studies have explored this issue, there is still little consensus regarding the exact nature of the patients' deficits. Moreover, the focus of most studies has been on ambiguity resolution in short, single-sentence contexts, so less is known about the impact of LH and RH damage on ambiguity resolution in larger contexts. Aims: The goal of the present study was to investigate sensitivity to a global (i.e., two-sentence) context during lexical ambiguity resolution in LHD and RHD patients relative to a group of control participants with no neurological impairment. Control participants were expected to activate only contextually appropriate meanings. In contrast, LHD patients were expected to have difficulty activating ambiguous word meanings or selecting contextually appropriate meanings. RHD patients were expected to have difficulty using context or suppressing contextually inappropriate meanings. Methods & Procedures: Three groups of participants took part in this study: 10 LHD patients with nonfluent aphasia, 8 RHD patients, and 9 age-matched control participants. A cross-modal sentence priming task was employed where participants first listened to a biased two-sentence passage ending in an ambiguous word. After each passage a visual target word, related to either the first or second meaning of the ambiguous word, was presented for lexical decision. Reaction time data were analysed using a repeated-measures ANOVA. Priming effects were tested by way of planned comparisons. Outcomes & Results: The performance of both patient groups differed markedly from that of the control group, who only showed priming for contextually appropriate meanings. The LHD patients did not exhibit any significant priming of ambiguous word meanings, whereas the RHD patients only showed priming for the most frequent or dominant meaning of ambiguous words (e.g., the “animal” meaning as opposed to the “emblem” meaning of seal) regardless of context. Conclusions: Both LH and RH damage can disrupt the process of ambiguity resolution in a global context. Specifically, LH damage is argued to impair the degree of activation of ambiguous word meanings or the time course of meaning activation, while RH damage seems to impair the use of context, leading to frequency-based meaning activation.