Garden-path utterances and relevance

An appropriate account of how the interpretation process of garden-path utterances develops should include an analysis of those psycholinguistic aspects related to the recovery of the semantic representations of the utterance as well as a pragmatic explanation of how those representations are used in the construction of a final interpretation. To investigate how lexical access could take place in the case of ambiguous words, two psycholinguistic models are briefly reviewed: the selective model and the exhaustive model. An argument is put forward for the exhaustive model, that is, for a modular view of the lexical processing system. Thus, we argue that in the processing of a garden-path utterance, upon encountering an ambiguous word, all of its meanings are initially activated. Once access has been completed and the selection phase reached, pragmatic factors come into play, in the process of selecting one of the possibilities and building an interpretation from it. Relevance theory, a cognitive-pragmatic account of communication, explains why a given interpretation is initially selected, why it is later rejected as contextually inappropriate and why the processor tries a second line of interpretation which will finally produce the desired results

Settling Into Semantic Space: An Ambiguity-Focused Account of Word-Meaning Access

Most words are ambiguous: Individual word forms (e.g., run) can map onto multiple different interpretations depending on their sentence context (e.g., the athlete/politician/river runs). Models of word-meaning access must therefore explain how listeners and readers can rapidly settle on a single, contextually appropriate meaning for each word that they encounter. I present a new account of word-meaning access that places semantic disambiguation at its core and integrates evidence from a wide variety of experimental approaches to explain this key aspect of language comprehension. The model has three key characteristics. (a) Lexical-semantic knowledge is viewed as a high-dimensional space; familiar word meanings correspond to stable states within this lexical-semantic space. (b) Multiple linguistic and paralinguistic cues can influence the settling process by which the system resolves on one of these familiar meanings. (c) Learning mechanisms play a vital role in facilitating rapid word-meaning access by shaping and maintaining high-quality lexical-semantic knowledge throughout the life span. In contrast to earlier models of word-meaning access, I highlight individual differences in lexical-semantic knowledge: Each person's lexicon is uniquely structured by specific, idiosyncratic linguistic experiences

The resolution of lexical ambiguity : evidence from an eye movement priming paradigm.

Two experiments investigated how textual context is used to disambiguate lexically ambiguous words. Previous research had suggested that context did not guide access toward the contextually appropriate meaning but instead selected this meaning from multiple activated meanings at a later stage of processing. The experiments reported here developed and used a new technique to explore the very early stages of word recognition. Eye movements were measured during reading. In both experiments a prime word was briefly displayed during the initial part of the fixation on the target word. Priming was measured by comparing fixation times on targets preceded by semantically Related versus Unrelated primes. Experiment 1 showed significant priming effects at a 35 ms prime duration but not at 30 or 25 ms prime durations. In Experiment 2, lexically ambiguous words were used as primes to targets in short passages and were presented for 35 ms. The type of preceding context (Consistent vs. Inconsistent), type of ambiguous prime (Biased vs. Balanced), and strength of instantiated meaning (Dominant vs. Subordinate) were varied. Only when the preceding context was Consistent with the Dominant meaning of a Biased ambiguous word were significant priming effects obtained. These results supported a model of lexical access in which context does guide access toward the contextually appropriate meaning of an ambiguous word

Resolving Semantic Ambiguities in Sentences: Cognitive Processes and Brain Mechanisms

fMRI studies of how the brain processes sentences containing semantically ambiguous words have consistently implicated (i) the left inferior frontal gyrus (LIFG) and (ii) posterior regions of the left temporal lobe in processing high-ambiguity sentences. This article reviews recent findings on this topic and relates them to (i) psycholinguistic theories about the underlying cognitive processes and (ii) general neuro-cognitive accounts of the relevant brain regions. We suggest that the LIFG plays a general role in the cognitive control process that are necessary to select contextually relevant meanings and to reinterpret sentences that were initially misunderstood, but it is currently unclear whether these control processes should best be characterised in terms of specific processes such as conflict resolution and controlled retrieval that are required for high-ambiguity sentences, or whether its function is better characterised in terms of a more general set of ‘unification’ processes. In contrast to the relatively rapid progress that has been made in understanding the function of the LIFG, we suggest that the contribution of the posterior temporal lobe is less well understood and future work is needed to clarify its role in sentence comprehension

Semantic Priming Effects in Lexical Ambiguity Resolution

The study addresses a number of issues related to the effects of biasing semantic contexts on the processing of words with more than one meaning (homographs). Biasing contexts have been taken to either constrain “lexical access” to a contextually relevant meaning of a homograph (selective access), or to exert a selective effect only after access to all, or some subset of, the meanings of a homograph (multiple access). Recent findings based on the two-factor theory of attention (Posner & Snyder, 1975a) suggest that lexical access occurs in two stages, where the first stage involves automatic activation of all meanings and the second involves a rapid attentional selection of the contextually relevant meaning. A three word priming paradigm (Schvaneveldt, Meyer, & Becker, 1976) was employed to test the stages hypothesis. Subjects were required to name only the final target word, and their reaction time was the dependent variable. The critical trials involved presentation of the two word primes, where the first prime was a word related to one meaning of the second prime, which was a homograph. The comparison of most interest was between targets that were semantically congruent or incongruent with the biased homograph (e.g., oar-row-PADDLE and oar-row-COLUMN, respectively). These conditions were compared to two baselines: One employing two neutral primes (e.g., xxxxx-xxxxx-PADDLE), and one employing the biased homograph followed by an unrelated target (e.g., oar-row-GREEN). The stimulus onset asynchtrony (SOA) of the homograph was varied, as well as the strategies that subjects were instructed to use in attending to the context stimuli. Some evidence was found for the stages view of ambiguity resolution: At brief SOAs, congruent and incongruent targets were facilitated, whereas at a longer SOA, facilitation was significantly reduced for incongruent targets. Attentional strategies had less effect than anticipated. Also, results with the neutral baseline were discrepant with earlier findings. Discussion focused on the research hypotheses and characteristics of the naming task that might account for the discrepant findings. A brief theoretical overview concluded

Context-dependent lexical ambiguity resolution: MEG evidence for the time-course of activity in left inferior frontal gyrus and posterior middle temporal gyrus

An MEG study investigated the role of context in semantic interpretation by examining the comprehension of ambiguous words in contexts leading to different interpretations. We compared high-ambiguity words in minimally different contexts (to bowl, the bowl) to low-ambiguity counterparts (the tray, to flog). Whole brain beamforming revealed the engagement of left inferior frontal gyrus (LIFG) and posterior middle temporal gyrus (LPMTG). Points of interest analyses showed that both these sites showed a stronger response to verb-contexts by 200 ms post-stimulus and displayed overlapping ambiguity effects that were sustained from 300 ms onwards. The effect of context was stronger for high-ambiguity words than for low-ambiguity words at several different time points, including within the first 100 ms post-stimulus. Unlike LIFG, LPMTG also showed stronger responses to verb than noun contexts in low-ambiguity trials. We argue that different functional roles previously attributed to LIFG and LPMTG are in fact played out at different periods during processing

Issues of Ambiguity in Sesotho: Meaning Retrieval

Published ArticleThis paper is based on the findings from a study conducted to examine issues of ambiguity in Sesotho. This is a qualitative study in which two experiments were conducted to collect data from 30 Sesotho native speakers. The respondents were purposefully selected from language users in Motheo district in South Africa. The results from these experiments showed that native speakers are able to distinguish a dominant meaning of a word from a subordinate meaning. They are able to assess the role of context in determining the meaning(s) of words. The implications of these findings are discussed. This paper provide an insight as to how context should be regarded as crucial in meaning retrieval. That in the absence of ‘context’, or if it is less restrictive, the most frequent occurring meaning will be activated

Accessing, integrating and inhibiting word meaning in poor comprehenders

This study examined three processes crucial to reading comprehension (semantic access, integration, and inhibition) to identify causes of comprehension impairment. Poor comprehenders were compared to chronological-age controls and vocabulary-age (VA) controls. When listening to homonym primes (“bank”) versus unrelated primes, controls were faster to name pictures related to dominant (money) and subordinate (river) meanings at 250 ms interstimulus interval (ISI) but only showed dominant priming at 1,000 ms ISI, whereas poor comprehenders only showed dominant priming. When listening to subordinately biased sentences ending in homonyms (“John fished from the bank”) versus control sentences, all groups showed priming when naming subordinate (appropriate) pictures at 250 ms ISI: VA controls and poor comprehenders also showed priming when naming dominant (inappropriate) pictures. At 1,000 ms ISI, controls showed appropriate priming, whereas poor comprehenders only showed inappropriate priming. These findings suggest that poor comprehenders have difficulties accessing subordinate word meanings, which can manifest as a failure to inhibit irrelevant information

Lexical access in the processing of word boundary ambiguity

Language ambiguity results from, among other things, the vagueness of the syntactic structure of phrases and whole sentences. Numerous types of syntactic ambiguity are associated with the placement of the phrase boundary. A special case of the segmentation problem is the phenomenon of word boundary ambiguities; in spoken natural language words coalesce, making it possible to interpret them in different ways (e.g., a name vs. an aim). The purpose of the study was to verify whether the two meanings of words with boundary ambiguities are activated, or whether it is a case of semantic context priming. The study was carried out using the cross-modality semantic priming paradigm. Sentences containing phrases with word boundary ambiguities were presented in an auditory manner to the participants. Immediately after, they performed a visual lexical decision task. Results indicate that both meanings of the ambiguity are automatically activated - independently of the semantic context. When discussing the results I refer to the autonomous and interactive models of parsing, and show other possible areas of research concerning word boundary ambiguities