Representation Of Word Meaning Research Articles

Strukturel semantik og formel leksikalsk repræsentation

This paper deals with lexical semantics from a European structuralist point of view. Three fundamentals of the tradition are treated: 1) 'meaning' viewed as 'sense' and not 'reference', 2) the semantic interdependence between words, and 3) componential analysis of lexical meaning. The structuralist approach to lexical semantics is commented upon with respect to its adequacy as a theory for the description of word meaning and to its explicitness in view of a formal representation of word meaning.

Emphasising sound and meaning: pitch gestures enhance Mandarin lexical tone acquisition

Lexical tones – pitches differentiating between word meanings in tonal languages – are particularly difficult for atonal language speakers to learn. To test the hypotheses of embodied cognition and spoken word recognition, we examined whether – and how – gesture could facilitate English speakers' discrimination between Mandarin words differing in lexical tone. Words were learned with gestures conveying tone pitch contours (pitch gestures), gestures conveying word meanings (semantic gestures) or no gestures. The results demonstrated that pitch gestures enhanced English speakers' discrimination between the meanings of Mandarin words differing in tone, whereas semantic gestures hindered their identification of tones in learned words. These findings indicate that the visuospatial features of pitch gestures strengthen the relationship between English speakers' representations of Mandarin lexical tones and word meanings, supporting the predictions of spoken word recognition and embodied cognition.

Composition in Distributional Semantics

AbstractDistributional Semantic Models, which automatically induce word meaning representations from naturally occurring textual data, are a success story of computational linguistics. Recently, there has been much interest in whether such models, endowed with a compositional component, can also successfully approximate the meaning of phrases and sentences. In this article, mostly addressed to theoretical linguists curious about distributional semantics, I first discuss why developing compositional Distributional Semantic Models is an interesting and important pursuit, and then I survey current ideas about how this can be achieved.

Fine-Grained Semantic Categorization across the Abstract and Concrete Domains

A consolidated approach to the study of the mental representation of word meanings has consisted in contrasting different domains of knowledge, broadly reflecting the abstract-concrete dichotomy. More fine-grained semantic distinctions have emerged in neuropsychological and cognitive neuroscience work, reflecting semantic category specificity, but almost exclusively within the concrete domain. Theoretical advances, particularly within the area of embodied cognition, have more recently put forward the idea that distributed neural representations tied to the kinds of experience maintained with the concepts' referents might distinguish conceptual meanings with a high degree of specificity, including those within the abstract domain. Here we report the results of two psycholinguistic rating studies incorporating such theoretical advances with two main objectives: first, to provide empirical evidence of fine-grained distinctions within both the abstract and the concrete semantic domains with respect to relevant psycholinguistic dimensions; second, to develop a carefully controlled linguistic stimulus set that may be used for auditory as well as visual neuroimaging studies focusing on the parametrization of the semantic space beyond the abstract-concrete dichotomy. Ninety-six participants rated a set of 210 sentences across pre-selected concrete (mouth, hand, or leg action-related) and abstract (mental state-, emotion-, mathematics-related) categories, with respect either to different semantic domain-related scales (rating study 1), or to concreteness, familiarity, and context availability (rating study 2). Inferential statistics and correspondence analyses highlighted distinguishing semantic and psycholinguistic traits for each of the pre-selected categories, indicating that a simple abstract-concrete dichotomy is not sufficient to account for the entire semantic variability within either domains.

What do we know when we claim to know nothing? Partial knowledge of word meanings may be ontological, but not hierarchical

AbstractTwo studies investigated whether knowledge about ontological category membership exists early in the word learning process—specifically, when words are partially known—and if so, how such knowledge is represented. Participants made decisions about the ontological category membership of words at three levels of knowledge: words they correctly defined (known), words recognized as familiar (frontier), and words mistakenly identified as nonwords (unknown). Accuracy on this task improved as a function of word level. Participants were able to identify the broad ontological categories to which words at all three levels of knowledge belonged, as well as the more specific ontological categories to which the words belonged. Overall, results indicated that knowledge about ontological category membership is available for words at very low levels of knowledge, and that this knowledge does not necessarily follow the strict hierarchical organization some ontological systems are thought to embody (e.g. Keil 1979). Implications for the acquisition and representation of word meanings are discussed.

Arbitrary Symbolism in Natural Language Revisited: When Word Forms Carry Meaning

Cognitive science has a rich history of interest in the ways that languages represent abstract and concrete concepts (e.g., idea vs. dog). Until recently, this focus has centered largely on aspects of word meaning and semantic representation. However, recent corpora analyses have demonstrated that abstract and concrete words are also marked by phonological, orthographic, and morphological differences. These regularities in sound-meaning correspondence potentially allow listeners to infer certain aspects of semantics directly from word form. We investigated this relationship between form and meaning in a series of four experiments. In Experiments 1–2 we examined the role of metalinguistic knowledge in semantic decision by asking participants to make semantic judgments for aurally presented nonwords selectively varied by specific acoustic and phonetic parameters. Participants consistently associated increased word length and diminished wordlikeness with abstract concepts. In Experiment 3, participants completed a semantic decision task (i.e., abstract or concrete) for real words varied by length and concreteness. Participants were more likely to misclassify longer, inflected words (e.g., “apartment”) as abstract and shorter uninflected abstract words (e.g., “fate”) as concrete. In Experiment 4, we used a multiple regression to predict trial level naming data from a large corpus of nouns which revealed significant interaction effects between concreteness and word form. Together these results provide converging evidence for the hypothesis that listeners map sound to meaning through a non-arbitrary process using prior knowledge about statistical regularities in the surface forms of words.

Effector-specific motor activation modulates verb production

Language comprehension studies have demonstrated that effector-specific activation of the motor system supports the representation of word meaning. The aim of the present study was to test whether motor activation is also relevant for verb production. In the first part of the experiment, participants named photographs of actions either in effector-homogeneous blocks, with all actions involving the same effector, or effector-heterogeneous blocks, with actions involving different effectors. Action-naming latencies were longer in homogeneous blocks, indicating the activation of effector information. In the second part of the experiment, the same participants named action pictures in random order, while performing a motor task with either their hand or foot. The motor task caused interference for action-picture naming: latencies were longer when the effector of the depicted action was congruent with the effector of the action used in the motor task. While these results do not exclude the existence of abstract semantic representations, they indicate that effector-specific effects found in language comprehension extend to language production.

Implicit and Explicit Mechanisms of Word Learning in a Narrative Context: An Event-related Potential Study

The vast majority of word meanings are learned simply by extracting them from context rather than by rote memorization or explicit instruction. Although this skill is remarkable, little is known about the brain mechanisms involved. In the present study, ERPs were recorded as participants read stories in which pseudowords were presented multiple times, embedded in consistent, meaningful contexts (referred to as meaning condition, M+) or inconsistent, meaningless contexts (M-). Word learning was then assessed implicitly using a lexical decision task and explicitly through recall and recognition tasks. Overall, during story reading, M- words elicited a larger N400 than M+ words, suggesting that participants were better able to semantically integrate M+ words than M- words throughout the story. In addition, M+ words whose meanings were subsequently correctly recognized and recalled elicited a more positive ERP in a later time window compared with M+ words whose meanings were incorrectly remembered, consistent with the idea that the late positive component is an index of encoding processes. In the lexical decision task, no behavioral or electrophysiological evidence for implicit priming was found for M+ words. In contrast, during the explicit recognition task, M+ words showed a robust N400 effect. The N400 effect was dependent upon recognition performance, such that only correctly recognized M+ words elicited an N400. This pattern of results provides evidence that the explicit representations of word meanings can develop rapidly, whereas implicit representations may require more extensive exposure or more time to emerge.

Dissociation and association of the embodied representation of tool-use verbs and hand verbs: An fMRI study

Embodied semantic theories suppose that representation of word meaning and actual sensory-motor processing are implemented in overlapping systems. According to this view, association and dissociation of different word meaning should correspond to dissociation and association of the described sensory-motor processing. Previous studies demonstrate that although tool-use actions and hand actions have overlapping neural substrates, tool-use actions show greater activations in frontal–parietal–temporal regions that are responsible for motor control and tool knowledge processing. In the present study, we examined the association and the dissociation of the semantic representation of tool-use verbs and hand action verbs. Chinese verbs describing tool-use or hand actions without tools were included, and a passive reading task was employed. All verb conditions showed common activations in areas of left middle frontal gyrus, left inferior frontal gyrus (BA 44/45) and left inferior parietal lobule relative to rest, and all conditions showed significant effects in premotor areas within the mask of hand motion effects. Contrasts between tool-use verbs and hand verbs demonstrated that tool verbs elicited stronger activity in left superior parietal lobule, left middle frontal gyrus and left posterior middle temporal gyrus. Additionally, psychophysiological interaction analyses demonstrated that tool verbs indicated greater connectivity among these regions. These results suggest that the brain regions involved in tool-use action processing also play more important roles in tool-use verb processing and that similar systems may be responsible for word meaning representation and actual sensory-motor processing.

How specifically are action verbs represented in the neural motor system: An fMRI study

Embodied accounts of language processing suggest that sensorimotor areas, generally dedicated to perception and action, are also involved in the processing and representation of word meaning. Support for such accounts comes from studies showing that language about actions selectively modulates the execution of congruent and incongruent motor responses (e.g., Glenberg & Kaschak, 2002), and from functional neuroimaging studies showing that understanding action-related language recruits sensorimotor brain areas (e.g. Hauk, Johnsrude, & Pulvermueller, 2004). In the current experiment we explored the basis of the neural motor system's involvement in representing words denoting actions. Specifically, we investigated whether the motor system's involvement is modulated by the specificity of the kinematics associated with a word. Previous research in the visual domain indicates that words denoting basic level category members lacking a specific form (e.g., bird) are less richly encoded within visual areas than words denoting subordinate level members (e.g., pelican), for which the visual form is better specified (Gauthier, Anderson, Tarr, Skudlarski, & Gore, 1997). In the present study we extend these findings to the motor domain. Modulation of the BOLD response elicited by verbs denoting a general motor program (e.g., to clean) was compared to modulation elicited by verbs denoting a more specific motor program (e.g., to wipe). Conform with our hypothesis, a region within the bilateral inferior parietal lobule, typically serving the representation of action plans and goals, was sensitive to the specificity of motor programs associated with the action verbs. These findings contribute to the growing body of research on embodied language representations by showing that the concreteness of an action-semantic feature is reflected in the neural response to action verbs.

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 they when are from different grammatical classes (noun-verb homonyms).

Body-Specific Representations of Action Verbs

According to theories of embodied cognition, understanding a verb like throw involves unconsciously simulating the action of throwing, using areas of the brain that support motor planning. If understanding action words involves mentally simulating one’s own actions, then the neurocognitive representation of word meanings should differ for people with different kinds of bodies, who perform actions in systematically different ways. In a test of the body-specificity hypothesis, we used functional magnetic resonance imaging to compare premotor activity correlated with action verb understanding in right- and left-handers. Right-handers preferentially activated the left premotor cortex during lexical decisions on manual-action verbs (compared with nonmanual-action verbs), whereas left-handers preferentially activated right premotor areas. This finding helps refine theories of embodied semantics, suggesting that implicit mental simulation during language processing is body specific: Right- and left-handers, who perform actions differently, use correspondingly different areas of the brain for representing action verb meanings.

Effects of word frequency on semantic memory in schizophrenia: Electrophysiological evidence for a deficit in linguistic access

Background Abnormal storage and/or access are among the hypothesized causes of semantic memory deficit in schizophrenia. Neuropsychological and connectionist models have emphasized functional systems that serve the processing of word meaning and frequency: semantic storage disturbance is presumed to result from weak representations of word meaning; defective access is assumed to result from compromises to pathways that activate word frequency knowledge. Candidate biological systems include neuromodulatory pathways that normally function to enhance neural signals (e.g., cholinergic system). Electrophysiological responding may be informative regarding the storage-access distinction for schizophrenia. Methods Visual event-related potentials were recorded for 14 schizophrenia outpatients receiving atypical antipsychotics, and 14 healthy controls group-matched to patients on age, gender, and demographics. N400 was elicited using an incidental semantic priming paradigm, in which semantic relatedness and word frequency were varied, and a letter probe task. Results Compared to controls, patients showed reduced N400 (µV) discrimination of semantic relatedness. Groups also showed different patterns of N400 to word frequency. Controls' N400 increased in negativity as words decreased in frequency of occurrence, while patients did not show a linear relationship between N400 and word frequency. Groups also differed for N400 to frequently occurring words. Patients exhibited increased negativity to high and very high frequency words, compared to controls. A subgroup of patients receiving antipsychotics with known affinity binding for muscarinic receptors (clozapine and olanzapine) showed significant albeit limited N400 priming, but their N400 to word frequency remained nonsignificant. Conclusions Results suggest a deficit in semantic access for schizophrenia, as well as an influence of neuromodulators on the activation of connections among semantic representations. Cumulative findings indicating only limited N400 priming for patients receiving either typical or atypical antipsychotics support the hypothesis that semantic memory deficit represents a trait marker for schizophrenia.

Body-specific representations of action verbs: Neural evidence from right- and left-handers

According to theories of embodied cognition, understanding a verb like throw involves unconsciously simulating the action of throwing, using areas of the brain that support motor planning. If understanding action words involves mentally simulating one's own actions, then the neurocognitive representation of word meanings should differ for people with different kinds of bodies, who perform actions in systematically different ways. In a test of the body-specificity hypothesis, we used functional magnetic resonance imaging to compare premotor activity correlated with action verb understanding in right- and left-handers. Right-handers preferentially activated the left premotor cortex during lexical decisions on manual-action verbs (compared with nonmanual-action verbs), whereas left-handers preferentially activated right premotor areas. This finding helps refine theories of embodied semantics, suggesting that implicit mental simulation during language processing is body specific: Right- and left-handers, who perform actions differently, use correspondingly different areas of the brain for representing action verb meanings.

Word Sense Disambiguation: An Overview

AbstractWord sense disambiguation is a subfield of computational linguistics in which computer systems are designed to determine the appropriate meaning of a word as it appears in the linguistic context. This article provides a survey of what has been done in this area: the ways that word meaning can be represented in the computer, the approaches taken by systems, how performance is evaluated and an overview of the intended applications that might benefit from this technology. One of the major issues has been, and still remains, that of finding an appropriate computational representation of word meaning as this is fundamental to the performance and utility of systems.

Mirror neurons, the representation of word meaning, and the foot of the third left frontal convolution

Previous neuroimaging research has attempted to demonstrate a preferential involvement of the human mirror neuron system (MNS) in the comprehension of effector-related action word (verb) meanings. These studies have assumed that Broca’s area (or Brodmann’s area 44) is the homologue of a monkey premotor area (F5) containing mouth and hand mirror neurons, and that action word meanings are shared with the mirror system due to a proposed link between speech and gestural communication. In an fMRI experiment, we investigated whether Broca’s area shows mirror activity solely for effectors implicated in the MNS. Next, we examined the responses of empirically determined mirror areas during a language perception task comprising effector-specific action words, unrelated words and nonwords. We found overlapping activity for observation and execution of actions with all effectors studied, i.e., including the foot, despite there being no evidence of foot mirror neurons in the monkey or human brain. These “mirror” areas showed equivalent responses for action words, unrelated words and nonwords, with all of these stimuli showing increased responses relative to visual character strings. Our results support alternative explanations attributing mirror activity in Broca’s area to covert verbalisation or hierarchical linearisation, and provide no evidence that the MNS makes a preferential contribution to comprehending action word meanings.

Action word meaning representations in cytoarchitectonically defined primary and premotor cortices

Recent models of language comprehension have assumed a tight coupling between the semantic representations of action words and cortical motor areas. We combined functional MRI with cytoarchitectonically defined probabilistic maps of left hemisphere primary and premotor cortices to analyse responses of functionally delineated execution- and observation-related regions during comprehension of action word meanings associated with specific effectors (e.g., punch, bite or stomp) and processing of items with various levels of lexical information (non body part-related meanings, nonwords, and visual character strings). The comprehension of effector specific action word meanings did not elicit preferential activity corresponding to the somatotopic organisation of effectors in either primary or premotor cortex. However, generic action word meanings did show increased BOLD signal responses compared to all other classes of lexical stimuli in the pre-SMA. As expected, the majority of the BOLD responses elicited by the lexical stimuli were in association cortex adjacent to the motor areas. We contrast our results with those of previous studies reporting significant effects for only 1 or 2 effectors outside cytoarchitectonically defined motor regions and discuss the importance of controlling for potentially confounding lexical variables such as imageability. We conclude that there is no strong evidence for a somatotopic organisation of action word meaning representations and argue the pre-SMA might have a role in maintaining abstract representations of action words as instructional cues.

Body-specific representations of action word meanings in right and left handers

AbstractIf understanding action words involves mentally simulating our own actions, then the neurocognitive representation of word meanings must differ for people with different kinds of bodies, who perform actions in systematically different ways. In a test of the Body-Specificity Hypothesis, right- and left-handers were compared on two motor-meaning congruity tasks. Double dissociations in both action execution and recognition memory results showed that right and left handers form body-specific representations of words for manual actions.

Extracting semantic representations from word co-occurrence statistics: A computational study

The idea that at least some aspects of word meaning can be induced from patterns of word co-occurrence is becoming increasingly popular. However, there is less agreement about the precise computations involved, and the appropriate tests to distinguish between the various possibilities. It is important that the effect of the relevant design choices and parameter values are understood if psychological models using these methods are to be reliably evaluated and compared. In this article, we present a systematic exploration of the principal computational possibilities for formulating and validating representations of word meanings from word co-occurrence statistics. We find that, once we have identified the best procedures, a very simple approach is surprisingly successful and robust over a range of psychologically relevant evaluation measures.

Children construct novel word meaning ad-hoc based on known words: Computational model of shape and material biases

Taking the stance that two well-known word learning biases (shape and material bias) are formed through learning (learned bias account, LBA), we illustrated a concrete computational mechanism with “ad-hoc meaning substitution (AMS)” hypothesis, and verified it by two computer simulations. AMS represents that when given a novel word and a corresponding instance, children create novel word meaning by using the known word meaning and the instance as an ad-hoc template. The AMS function enables fast mapping and vocabulary spurt. To describe the AMS process computationally, we introduced “word distributional prototype (WDP),” which is the explicit representation of word meaning with an inductive learning function. Simulation 1 revealed that when a network with WDP and AMS was given a biased vocabulary reflecting young children, it demonstrated shape, material, and overgeneralized shape biases. This result suggested that a triad of word meaning induction, ad-hoc meaning substitution, and early biased vocabulary is essential for the emergence of biases. Simulation 2 introduced the notion of maturity that denoted a degree of learning convergence for each word meaning, and then the network showed neither shape nor material bias during an early small vocabulary. This result indicated that the period at which each bias emerges is decided by maturity. Though AMS consists of simpler and valider mechanisms than those proposed in previous studies, it could reproduce behavior of shape and material biases and explain their emergence process clearly. These results suggest that phenomena concerning shape and material biases are explicable with a simple ad-hoc learning instead of meta-learning among LBA or innate language-specific ones.