Strength of discourse context as a determinant of the subordinate bias effect

Learning about the meanings of ambiguous words: evidence from a word-meaning priming paradigm with short narratives

Fluent language comprehension requires people to rapidly activate and integrate context-appropriate word meanings. This process is challenging for meanings of ambiguous words that are comparatively lower in frequency (e.g., the "bird" meaning of "crane"). Priming experiments have shown that recent experience makes such subordinate (less frequent) word meanings more readily available at the next encounter. These experiments used lists of unconnected sentences in which each ambiguity was disambiguated locally by neighbouring words. In natural language, however, disambiguation may occur via more distant contextual cues, embedded in longer, connected communicative contexts. In the present experiment, participants (N = 51) listened to 3-sentence narratives that ended in an ambiguous prime. Cues to disambiguation were relatively distant from the prime; the first sentence of each narrative established a situational context congruent with the subordinate meaning of the prime, but the remainder of the narrative did not provide disambiguating information. Following a short delay, primed subordinate meanings were more readily available (compared with an unprimed control), as assessed by responses in a word association task related to the primed meaning. This work confirms that listeners reliably disambiguate spoken ambiguous words on the basis of cues from wider narrative contexts, and that they retain information about the outcome of these disambiguation processes to inform subsequent encounters of the same word form.

Gesture style can affect the integration of gestures and speech: the evidence from Chinese ERP research

People often accompany gestures in the process of speaking, but the individual's gesture style is not the same. The present study uses the ambiguity resolution paradigm to explore the influence of two kinds of gesture styles on gesture-verbal comprehension. The study manipulated the gesture styles and meaning types of target words and recorded N400 amplitude. This study found that (1) in the non-grooming condition, compared with the situation where the gesture and semantics are inconsistent, a smaller N400 appears under the consistent condition; (2) in the grooming condition, the grooming gesture will reduce the effect of the iconic gesture on speech understanding. N400 amplitude increased only in the case of matching between dominant meaning gesture and subordinate meaning target word. These results suggest that the communication styles of gestures of different speakers, in the process of speech comprehension, affect how well listeners integrate gestures and language.

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.

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

PURPOSE

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.

METHOD

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.

RESULTS

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.

CONCLUSIONS

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.

The N400 elicited by homonyms in puns: Two primes are not better than one

To comprehend a pun involving a homonym (e.g., The prince with a bad tooth got a crown), both meanings of the homonym must be accessed and selected. Previous ERP studies have shown that the N400 reflects lexicosemantic processing, but none have directly investigated the N400 elicited by homonyms in the unique context of puns. Here, N400 priming effects showed that the dual context of puns (e.g., the primes prince and tooth) did not facilitate homonym processing in comparison to single dominant biasing (e.g., The prince with a bad leg got a crown) or subordinate biasing (e.g., The adult with a bad tooth got a crown) conditions. However, homonyms did elicit a less negative N400 (i.e., priming) in the pun condition in comparison to the neutral context condition (e.g., The adult with a bad leg got a crown). These findings are interpreted in terms of the dominant advantage and subordinate bias effect posited by the reordered access model of homonym processing, and in terms of N400 amplitude as an index of how consistently various sources of semantic featural information converge on one lexical item, even when two lexical items must be activated for comprehension.

A speaker's gesture style can affect language comprehension: ERP evidence from gesture-speech integration

In face-to-face communication, speech is typically enriched by gestures. Clearly, not all people gesture in the same way, and the present study explores whether such individual differences in gesture style are taken into account during the perception of gestures that accompany speech. Participants were presented with one speaker that gestured in a straightforward way and another that also produced self-touch movements. Adding trials with such grooming movements makes the gesture information a much weaker cue compared with the gestures of the non-grooming speaker. The Electroencephalogram was recorded as participants watched videos of the individual speakers. Event-related potentials elicited by the speech signal revealed that adding grooming movements attenuated the impact of gesture for this particular speaker. Thus, these data suggest that there is sensitivity to the personal communication style of a speaker and that affects the extent to which gesture and speech are integrated during language comprehension.

How meaning similarity influences ambiguous word processing: the current state of the literature

The majority of words in the English language do not correspond to a single meaning, but rather correspond to two or more unrelated meanings (i.e., are homonyms) or multiple related senses (i.e., are polysemes). It has been proposed that the different types of "semantically-ambiguous words" (i.e., words with more than one meaning) are processed and represented differently in the human mind. Several review papers and books have been written on the subject of semantic ambiguity (e.g., Adriaens, Small, Cottrell, & Tanenhaus, 1988; Burgess & Simpson, 1988; Degani & Tokowicz, 2010; Gorfein, 1989, 2001; Simpson, 1984). However, several more recent studies (e.g., Klein & Murphy, 2001; Klepousniotou, 2002; Klepousniotou & Baum, 2007; Rodd, Gaskell, & Marslen-Wilson, 2002) have investigated the role of the semantic similarity between the multiple meanings of ambiguous words on processing and representation, whereas this was not the emphasis of previous reviews of the literature. In this review, we focus on the current state of the semantic ambiguity literature that examines how different types of ambiguous words influence processing and representation. We analyze the consistent and inconsistent findings reported in the literature and how factors such as semantic similarity, meaning/sense frequency, task, timing, and modality affect ambiguous word processing. We discuss the findings with respect to recent parallel distributed processing (PDP) models of ambiguity processing (Armstrong & Plaut, 2008, 2011; Rodd, Gaskell, & Marslen-Wilson, 2004). Finally, we discuss how experience/instance-based models (e.g., Hintzman, 1986; Reichle & Perfetti, 2003) can inform a comprehensive understanding of semantic ambiguity resolution.

Activation of shape and semantic information during ambiguous homophone processing: eye tracking evidence from Hindi

In two visual world eye tracking studies, we examined the activation of subordinate meanings of ambiguous homophones in Hindi and particularly when the sentence context is biased towards the dominant meaning. Participants listened to sentences that were either neutral or biased towards the dominant meaning of the homophone and saw a display containing four pictures. In experiment 1, the display had a shape competitor of the subordinate meaning of the homophone in both neutral and biased conditions along with three unrelated distractors. Experiment 2 had semantic competitors of the subordinate meaning of the homophones along with three distractors. Proportion of fixations to different objects overtime suggested that participants activated the subordinate meanings and oriented their attention to the shape and semantic competitors even when the prior context was biased towards the dominant meaning. Overall, these data from Hindi provide further support to those models of lexical access that assume exhaustive access of both the meanings of an ambiguous homophone. These data suggest even a dominant bias does not eliminate the activation of perceptual and conceptual features of the subordinate meaning.

Eye Movements while Reading Biased Homographs: Effects of Prior Encounter and Biasing Context on Reducing the Subordinate Bias Effect

Readers experience processing difficulties when reading biased homographs preceded by subordinate-biasing contexts. Attempts to overcome this processing deficit have often failed to reduce the subordinate bias effect (SBE). In the present studies, we examined the processing of biased homographs preceded by single-sentence, subordinate-biasing contexts, and varied whether this preceding context contained a prior instance of the homograph or a control word/phrase. Having previously encountered the homograph earlier in the sentence reduced the SBE for the subsequent encounter, while simply instantiating the subordinate meaning produced processing difficulty. We compared these reductions in reading times to differences in processing time between dominant-biased repeated and non-repeated conditions in order to verify that the reductions observed in the subordinate cases did not simply reflect a general repetition benefit. Our results indicate that a strong, subordinate-biasing context can interact during lexical access to overcome the activation from meaning frequency and reduce the SBE during reading.

What Iconic Gesture Fragments Reveal about Gesture–Speech Integration: When Synchrony Is Lost, Memory Can Help

The present series of experiments explores several issues related to gesture–speech integration and synchrony during sentence processing. To be able to more precisely manipulate gesture–speech synchrony, we used gesture fragments instead of complete gestures, thereby avoiding the usual long temporal overlap of gestures with their coexpressive speech. In a pretest, the minimal duration of an iconic gesture fragment needed to disambiguate a homonym (i.e., disambiguation point) was therefore identified. In three subsequent ERP experiments, we then investigated whether the gesture information available at the disambiguation point has immediate as well as delayed consequences on the processing of a temporarily ambiguous spoken sentence, and whether these gesture–speech integration processes are susceptible to temporal synchrony. Experiment 1, which used asynchronous stimuli as well as an explicit task, showed clear N400 effects at the homonym as well as at the target word presented further downstream, suggesting that asynchrony does not prevent integration under explicit task conditions. No such effects were found when asynchronous stimuli were presented using a more shallow task (Experiment 2). Finally, when gesture fragment and homonym were synchronous, similar results as in Experiment 1 were found, even under shallow task conditions (Experiment 3). We conclude that when iconic gesture fragments and speech are in synchrony, their interaction is more or less automatic. When they are not, more controlled, active memory processes are necessary to be able to combine the gesture fragment and speech context in such a way that the homonym is disambiguated correctly.

Immediate disambiguation of lexically ambiguous words during reading: Evidence from eye movements

Sentences containing lexically ambiguous words were read as readers' eye movements were monitored. On half of the trials, the dominant meaning of the ambiguous word was instantiated, while in the other half, the subordinate meaning was instantiated. Furthermore, on half of the trials, an adjective or modifier immediately preceded the target noun (kitchen table, statistical table), which was consistent with either the dominant or subordinate meaning. The results of the experiment demonstrate that readers are able to immediately utilize the modifier to select the appropriate meaning of the ambiguous word.

Neural correlates of semantic competition during processing of ambiguous words

The current study investigated the neural correlates that underlie the processing of ambiguous words and the potential effects of semantic competition on that processing. Participants performed speeded lexical decisions on semantically related and unrelated prime-target pairs presented in the auditory modality. The primes were either ambiguous words (e.g., ball) or unambiguous words (e.g., athlete), and targets were either semantically related to the dominant (i.e., most frequent) meaning of the ambiguous prime word (e.g., soccer) or to the subordinate (i.e., less frequent) meaning (e.g., dance). Results showed increased activation in the bilateral inferior frontal gyrus (IFG) for ambiguous-related compared to unambiguous-related stimulus pairs, demonstrating that prefrontal areas are activated even in an implicit task where participants are not required to explicitly analyze the semantic content of the stimuli and to make an overt selection of a particular meaning based on this analysis. Additionally, increased activation was found in the left IFG and the left cingulate gyrus for subordinate meaning compared to dominant meaning conditions, suggesting that additional resources are recruited in order to resolve increased competition demands in accessing the subordinate meaning of an ambiguous word.

The influence of multiple primes on bottom-up and top-down regulation during meaning retrieval: evidence for 2 distinct neural networks

Meaning retrieval of a word can proceed fast and effortlessly or can be characterized by a controlled search for candidate lexical items and a subsequent selection process. In the current study, we facilitated meaning retrieval by increasing the number of words that were related to the final target word in a triplet (e.g., lion-stripes-tiger). To induce higher search and selection demands, we presented ambiguous words as targets (i.e., homonyms like ball) in half of the trials. Hereby, the dominant (game), low-frequent (dance), or both meanings of the homonym were primed. Participants performed a relatedness judgment during functional magnetic resonance imaging. Activation in a bilateral network (angular gyrus, rostromedial prefrontal cortex) increased linearly with multiple related primes, whereas the posterior left inferior prefrontal cortex (pLIPC) showed the reverse activation pattern for unambiguous trials. When homonyms served as targets, pLIPC responded strongest when both meanings or low-frequent concepts were addressed. Additional anterior left inferior prefrontal cortex activation was observed for the latter trials only. The data support an interaction between 2 distinct cerebral networks that can be linked to automatic bottom-up support and top-down control during meaning retrieval. They further imply a functional specialization of the LIPC along an anterior-posterior dimension.

Dominance and context effects on activation of alternative homophone meanings

Two eyetracking-during-listening experiments showed frequency and context effects on fixation probability for pictures representing multiple meanings of homophones. Participants heard either an imperative sentence instructing them to look at a homophone referent (Experiment 1) or a declarative sentence that was either neutral or biased toward the homophone's subordinate meaning (Experiment 2). At homophone onset in both experiments, the participants viewed four pictures: (1) a referent of one homophone meaning, (2) a shape competitor for a nonpictured homophone meaning, and (3) two unrelated filler objects. In Experiment 1, meaning dominance affected looks to both the homophone referent and the shape competitor. In Experiment 2, as compared with neutral contexts, subordinate-biased contexts lowered the fixation probability for shape competitors of dominant meanings, but shape competitors still attracted more looks than would be expected by chance. We discuss the consistencies and discrepancies of these findings with the selective access and reordered access theories of lexical ambiguity resolution.

Semantic adaptation and competition during word comprehension

Word comprehension engages the left ventrolateral prefrontal (lVLPFC) and posterior lateral-temporal cortices (PLTC). The contributions of these brain regions to comprehension remain controversial. We hypothesized that the PLTC activates meanings, whereas the lVLPFC resolves competition between representations. To test this hypothesis, we used functional magnetic resonance imaging (fMRI) to assess the independent effects of adaptation and competition on neural activity. Participants judged the relatedness of word pairs. Some consecutive pairs contained a common ambiguous word. The same or different meanings of this word were primed (e.g., SUMMER-FAN, CEILING-FAN; ADMIRER-FAN, CEILING-FAN). Based on the logic of fMRI adaptation, trials with more semantic overlap should produce more adaptation (less activation) in regions that activate meaning. In contrast, trials with more semantic ambiguity should produce more activation in regions that resolve competition. We observed a double dissociation between activity in the PLTC and lVLPFC. LPLTC activity depended on the amount of semantic overlap, irrespective of the amount of semantic ambiguity. In contrast, lVLPFC activity depended on the amount of semantic ambiguity. Moreover, across participants the size of the competition effect as measured by errors was correlated with the size of the competition effect in the lVLPFC. We conclude that the lVLPFC is an executive mechanism within language processing.

Understanding words in context: the role of Broca's area in word comprehension

What role does meaning selection play in word comprehension, and what neural systems support this selection process? Most words have multiple meanings and are therefore ambiguous. This is true of both homonymous words (words that have multiple unrelated meanings) and polysemous words (words that have multiple related meanings). The extant evidence indicates that meaning selection is an integral part of homonym comprehension. However, it is not known whether meaning selection extends to polysemous words, or what neural systems support meaning selection during comprehension. Prior neuroimaging and neuropsychological evidence suggest that the left inferior frontal gyrus (LIFG) may play a role in resolving competition during language processing. We therefore sought to test the hypotheses that meaning selection is part of polysemous word comprehension, and that the LIFG resolves meaning competition during word comprehension. We tested healthy participants on a version of the triplet lexical decision task, with polysemous and homonymous stimuli. Results suggest that the meanings of polysemous words, like the meanings of homonyms, are selected based on context. However, homonymous and polysemous words differed in how meaning frequency affected meaning selection. We then administered the triplet lexical decision task to patients with LIFG damage to examine whether this region plays a role in context-dependent meaning selection. Results support the hypothesis that the LIFG serves as a top-down biasing mechanism that facilitates rapid meaning selection during word comprehension. We conclude that context-dependent meaning selection is an integral part of word comprehension for both homonyms and polysemous words, and that the LIFG facilitates this selection process.

Development of lexical and sentence level context effects for dominant and subordinate word meanings of homonyms

Nine-ten-and twelve-year-old children (N = 75) read aloud dominant, subordinate or ambiguous bias sentences (N = 120) that ended in a homonym (BALL). After the sentence (1,000 ms), children read aloud targets that were related to the dominant (BAT) or subordinate (DANCE) meaning of the homonym or control targets. Participants were also divided into three reading skill groups based on an independent measure of single word oral reading accuracy. There were three main developmental and reading skill findings. First, 9-year-olds and low skill readers showed lexical level facilitation in accuracy. Second, 9- and 10-year-olds or low and moderate skill readers showed lexical level facilitation in reaction time. Third, 12-year-olds or high skill readers showed sentence level facilitation in reaction time with high skill readers additionally showing sentence level inhibition in reaction time. These results show that lexical level context effects decreased and that sentence level context effects increased with development and skill. These results are discussed in terms of connectionist models of visual word recognition that incorporate distributed attractor principles.

Situation-evoking stimuli, domain of reference, and the incremental interpretation of lexical ambiguity

In two experiments, we examined the influence of situation-evoking stimuli on the resolution of lexical ambiguity. In Experiment 1, we examined situation-evoking stimuli at an early NP position. Readers were asked to establish whether specific entities were likely to participate as agents in contextually defined situations. Naming latencies demonstrated that defined situations headed by likely agents evoked a domain of reference that included only the situation-appropriate meaning of a targeted lexical ambiguity. In contrast, defined situations headed by unlikely agents evoked a domain of reference that did not include either meaning of the intended ambiguous word. In Experiment 2, we examined situation-evoking stimuli at a later direct object position. The specificity of the theme/patient role filler was manipulated, where the linguistic expressions were either specific or general with respect to a given contextual situation. The results showed that contexts with specific situation-evoking stimuli were rated as strongly biased and provided a domain of reference for the immediate resolution of lexical ambiguity, whereas contexts with nonspecific role fillers were rated as ambiguous and provided a domain of reference that was supportive of both meanings of an ambiguous word. The results were discussed within a contextual-feature-sensitive model of language processing.

Number-of-features effects and semantic processing

Participants list many semantic features for some concrete nouns (e.g., lion) and fewer for others (e.g., lime; McRae, de Sa, & Seidenberg, 1997). Pexman, Lupker, and Hino (2002) reported faster lexical decision and naming responses for high number of features (NOF) words than for low-NOF words. In the present research, we investigated the impact of NOF on semantic processing. We observed NOF effects in a self-paced reading task when prior context was not congruent with the target word (Experiment 1) and in a semantic categorization task (concrete vs. abstract; Experiment 2A). When we narrowed our stimuli to include high- and low-NOF words from a single category (birds), we found substantial NOF effects that were modulated by the specificity of the categorization task (Experiments 3A, 3B, and 3C). We argue that these results provide support for distributed representation of word meaning.

Lexical Ambiguity Resolution Across Languages: A Theoretical and Empirical Review

Abstract. Words that involve completely different meanings across languages but possess significant overlap in form are referred to as homographic noncognates or interlexical homographs (e.g., red is a color word in English but means “net” in Spanish). An important question in the investigation of the processing of these words is whether or not both meaning and form are integral to their representation leading to language-specific processing of these items. In contrast, some theories have been put forth indicating that the processing of these words is nonselective with regards to language. Simply stated, when one of these words is encountered, all of the relevant meanings are accessed regardless of the specific demands of the task and the base language that is being used. In the present, critical review, evidence purported to favor each view is presented along with a discussion of the methodological and analytic constraints that moderate the reported findings. The data lead to the conclusion that there is a time course involved in the activation of multiple meanings such that a primary or dominant meaning (sometimes biased by frequency) is typically accessed more readily, followed by the opposite language meaning. These results indicated that studies should focus on manipulating the timing intervals between the presentation of these words and subsequent responses that are required by a particular task.

The processing of lexical ambiguity: homonymy and polysemy in the mental lexicon

Under the theoretical assumption that lexical ambiguity is not a homogeneous phenomenon, but rather that it is subdivided into two distinct types, namely homonymy and polysemy, the present study investigated whether these different types of lexical ambiguity are psychologically real. Four types of ambiguous words, homonymous words (e.g., "pen"), polysemous words with metaphorical extensions (e.g., "eye"), polysemous words with a count/mass metonymic extension (e.g., "turkey"), and polysemous words with a producer/product metonymic extension (e.g., "Dali"), were used in a cross-modal sentence-priming lexical decision task. Overall, the theoretical distinction between homonymy and polysemy was reflected in the results of the present study, which revealed differential processing depending on the type of ambiguity.

Strength of context does modulate the subordinate bias effect: a reply to Binder and Rayner

Using a self-paced reading task, Kellas, Martin, Yehling, Herman, and Vu (1995) demonstrated that strength of context can modulate the effects of meaning frequency. Binder and Rayner (1998) initially replicated the results, using eye-tracking methodology. On further examination of the stimuli, Binder and Rayner eliminated 43% of the stimulus set and found that context strength failed to modulate meaning frequency. Binder and Rayner's initial replication of Kellas et al. and the convergence of results between their two main experiments established the validity of self-paced reading as a measure of on-line reading, when compared with eye-tracking methodology. However, their central conclusion, that context strength cannot modulate the subordinate bias effect, is open to question. In this commentary, we examine the criteria adopted to exclude items from our homonym set and discuss the issue of local versus published norms. We also discuss the issue of context strength, as related to the specific rating procedures employed. Finally, we conclude that strong context can, in fact, eliminate the subordinate bias effect and that the context-sensitive model can more fully account for the available data on lexical ambiguity resolution.