THE EFFECT OF MEANING FREQUENCY ON PROCESSING LEXICALLY AMBIGUOUS WORDS: Evidence From Eye Fixations

Abstract —Subjects read sentences containing lexically ambiguous words while their eye movements were monitored Biased ambiguous words (those that have one highly dominant sense) were used m sentences containing a prior context that instantiated their subordinate sense Control words were matched m frequency both to the dominant and to the subordinate meaning of the ambiguous word (high- and low-frequency controls) Subjects fixated longer on both the ambiguous word and the low-frequence control than on the high-frequency control When the target was ambiguous, however, the duration of posttarget fixations was longer and the likelihood of making a regression to the target was greater than when the target was an unambiguous control The results are discussed m relation to current models of lexical ambiguity resolution     

Is phonological short-term memory related to phonological analysis stages in auditory sentence processing?

Despite extensive research, the role of phonological short-term memory (STM) during oral sentence comprehension remains unclear. We tested the hypothesis that phonological STM is involved in phonological analysis stages of the incoming words, but not in sentence comprehension per se. We compared phonological STM capacity and processing times for natural sentences and sentences containing phonetically ambiguous words. The sentences were presented for an auditory sentence anomaly judgement task and processing times for each word were measured. STM was measured via nonword and word immediate serial recall tasks, indexing phonological and lexicosemantic STM capacity, respectively. Significantly increased processing times were observed for phonetically ambiguous words, relative to natural stimuli in same sentence positions. Phonological STM capacity correlated with the size of this phonetic ambiguity effect. However, phonological STM capacity did not correlate with measures of later semantic integration processes while lexicosemantic STM did. This study suggests that phonological STM is associated with phonological analysis processes during sentence processing.     

Context and lexical access: implications of nonword interference for lexical ambiguity resolution

To eliminate potential "backward" priming effects, Glucksberg, Kreuz, and Rho (1986) introduced a variant of the cross-modal lexical priming task in which subjects made lexical decisions to nonword targets that were modeled on a word related to either the contextually biased or unbiased sense of an ambiguous word. Lexical decisions to nonwords were longer than controls only when the nonword was related to the contextually biased sense of the ambiguous word, leading Glucksberg et al. to conclude that context does constrain lexical access and that the multiple access pattern observed in previous studies was probably an artifact of backward priming. We did not find nonword interference when the nonword targets used by Glucksberg et al. were preceded by semantically related ambiguous or unambiguous word primes. However, we did replicate their sentence context results when the ambiguous words were removed from the sentences. We conclude that the interference obtained by Glucksberg et al. is due to postlexical judgements of the congruence of the sentence context and the target, not to context constraining lexical access.     

Priming dominant and unusual senses of ambiguous words

The priming technique was used to investigate the conditions under which a homograph’s dominant and/or nondominant semantic sense will be retrieved. Subjects verified whether “A(n) A is a(n) B” when A was an ambiguous word and B was a word corresponding to either a dominant or an unusual semantic sense of word A. When word B most often corresponded to the dominant sense of word A (Experiment I), a Priming by Dominance interaction was obtained in the reaction time (RT) data; viz, the facilitatory effect of priming was greater for the dominant-sense sentences than for the unusual-sense sentences. When the word B equally often corresponded to the dominant and unusual senses of A (Experiment 2), the facilitatory effect of priming was equal for the dominant-sense and unusual-sense sentences. These results were interpreted within the framework of a two-stage model of lexical access (d. Posner & Snyder, 1975; Neely, 1977). An application of this two-stage model to the now rather extensive literature on homographic processing helps clear up the apparent contradictions that have been prevalent in this literature.     

Levels of processing of normal and ambiguous sentences in different contexts

Summary An experiment was conducted to investigate the effect of depth of semantic analysis on the recall of sentences presented for comprehension. The depth of semantic analysis was varied by presenting 48 subjects with 24 unambiguous or lexically ambiguous sentences that were either preceded by a picture or not. Each picture showed either one or both interpretations of the respective ambiguous sentence. The sentence remained on display until the subject had pressed a key to indicate that he had understood its meaning. After the presentation of all the sentences the subjects were tested for recall. Ambiguous sentences were equally well understood as unambiguous sentences, but were better recalled when their ambiguity had been noticed. The subject's awareness of sentence ambiguity, and hence the depth of semantic analysis, was found to depend on the pictorial context in which the sentences were presentend. The pictorial context was also found to affect the depth of processing of unambiguous sentences, which, when presented without a picture, were more time-consuming in comprehension and less well recalled than when preceded by a picture. These findings provide the background for a discussion of the interrelations between the comprehension of sentences, the depth of their semantic processing, and the recall of these sentences.The author gratefully acknowledges the assistance of Lorenz Sichelschmidt in collecting and analyzing data and B. Jankowski in the translation of this paper from an original German version     

Untrained speakers' use of prosody in syntactic disambiguation and listeners' interpretations

We investigated how naively produced prosody affects listeners' end interpretations of ambiguous utterances. Non-professional speakers who were unaware of any ambiguity produced ambiguous sentences couched in short, unambiguous passages. In a forced-choice task, listeners could not tell which context the isolated ambiguous sentences came from (Exp. 1). However, listeners were able to correctly paraphrase the least ambiguous subset of these utterances, showing that prosody can be used to resolve ambiguity (Exp. 2). Nonetheless, in everyday language use, both prosody and context are available to interpret speech. When the least ambiguous sentences were cross-spliced into contexts biasing towards their original interpretations or into contexts biasing towards their alternative interpretations, answers to content questions about the ambiguous sentence, confidence ratings, and ratings of naturalness all indicated that prosody is ignored when context is available (Exp. 3). Although listeners can use prosody to interpret ambiguous sentences, they generally do not, and this makes sense in light of the frequent lack of reliable prosodic cues in everyday speech. Received: 3 April 1998 / Accepted: 21 October 1998     

Lexical complexity and fixation times in reading: Effects of word frequency,verb complexity,and lexical ambiguity

Two experiments investigated whether lexical complexity increases a word’s processing time. Subjects read sentences, each containing a target word, while their eye movements were monitored. In experiment 1, mean fixation time on infrequent words was longer than on their more frequent controls, as was the first fixation after the Infrequent Target. Fixation Times on Causative, factive, and negative verbs and ambiguous nouns were no longer than on their controls. Further analyses on the ambiguous nouns, however, suggested that the likelihood of their various meanings affected fixation time. This factor was investigated in experiment 2. subjects spent a longer time fixating ambiguous words with two equally likely meanings than fixating ambiguous words with one highly likely meaning. The results suggest that verb complexity does not affect lexical access time, and that word frequency And the presence of two highly likely meanings may affect lexical access and/or postaccess integration.     

Aging and the use of context in ambiguity resolution: complex changes from simple slowing

Older and younger adults' abilities to use context information rapidly during ambiguity resolution were investigated. In Experiments 1 and 2, younger and older adults heard ambiguous words (e.g., fires) in sentences where the preceding context supported either the less frequent or more frequent meaning of the word. Both age groups showed good context use in offline tasks, but only young adults demonstrated rapid use of context in cross-modal naming. A 3rd experiment demonstrated that younger and older adults had similar knowledge about the contexts used in Experiments 1 and 2. The experiment results were simulated in 2 computational models in which different patterns of context use were shown to emerge from varying a single speed parameter. These results suggest that age-related changes in processing efficiency can modulate context use during language comprehension.     

Event-related potential indices of ambiguous sentence processing

An event-related potential (ERP) probe was used to examine various models of ambiguous sentence processing. ERPs to light flashes were recorded during and immediately after auditorily presented ambiguous and unambiguous target sentences. Each target sentence was preceded by either a relevant or a neutral context sentence. Principal component analyses of the ERPs indicated that although certain components varied as a function of ambiguity, none of the components varied as a function of preceding context. These findings provided some support for a postdecision model of ambiguity processing which suggests that both meanings of an ambiguity are always processed, even when prior disambiguating context is available.     

Effects of syntactic category assignment on lexical ambiguity resolution in reading: an eye movement analysis

Readers' eye movements were monitored as they read sentences containing lexically ambiguous words whose meanings share a single syntactic category (e.g., calf), lexically ambiguous words whose meanings belong to different syntactic categories (e.g., duck), or unambiguous control words. Information provided prior to the target always unambiguously specified the context-appropriate syntactic-category assignment for the target. Fixation times were longer on ambiguous words whose meanings share a single syntactic category than on controls, both when prior context was semantically consistent with the subordinate interpretation of a biased ambiguous word (Experiment 1) and when prior context was semantically neutral as to the intended interpretation of a balanced ambiguous word (Experiment 2). These ambiguity effects, which resulted from differences in difficulty with meaning resolution, were not found when the ambiguity crossed syntactic categories. These data indicate that, in the absence of syntactic ambiguity, syntactic-category information mediates the semantic-resolution process.     

Context effects in word recognition: evidence for early interactive processing

This study investigated whether a prior context influenced lexical access as indexed by participants' electrophysiological response in the N1 from 132 to 192 ms poststimulus. Ambiguous, high-frequency (HF), and low-frequency (LF) words were presented in neutral and biasing contexts. Event-related potentials (ERPs) for ambiguous words were compared with those for unambiguous HF (word form) and LF (word meaning) control words. Word frequency effects in the N1 extended previous ERP findings. A marginal effect of context for LF words provided electrophysiological support for the context-by-frequency interaction shown in reaction time paradigms. In neutral context, responses to ambiguous words were comparable to responses to HF words, and in biasing context (where context instantiated the subordinate sense), responses to ambiguous words were comparable to responses to LF words. The results establish temporal parameters for the early operation of context in lexical access. These constraints are more consistent with an interactive than a modular account.     

Understanding words in sentence contexts: the time course of ambiguity resolution

Spoken language comprehension requires rapid integration of information from multiple linguistic sources. In the present study we addressed the temporal aspects of this integration process by focusing on the time course of the selection of the appropriate meaning of lexical ambiguities ("bank") in sentence contexts. Successful selection of the contextually appropriate meaning of the ambiguous word is dependent upon the rapid binding of the contextual information in the sentence to the appropriate meaning of the ambiguity. We used the N400 to identify the time course of this binding process. The N400 was measured to target words that followed three types of context sentences. In the concordant context, the sentence biased the meaning of the sentence-final ambiguous word so that it was related to the target. In the discordant context, the sentence context biased the meaning so that it was not related to the target. In the unrelated control condition, the sentences ended in an unambiguous noun that was unrelated to the target. Half of the concordant sentences biased the dominant meaning, and the other half biased the subordinate meaning of the sentence-final ambiguous words. The ISI between onset of the target word and offset of the sentence-final word of the context sentence was 100 ms in one version of the experiment, and 1250 ms in the second version. We found that (i) the lexically dominant meaning is always partly activated, independent of context, (ii) initially both dominant and subordinate meaning are (partly) activated, which suggests that contextual and lexical factors both contribute to sentence interpretation without context completely overriding lexical information, and (iii) strong lexical influences remain present for a relatively long period of time.     

Assessing resource demands during sentence processing in Parkinson's disease

Patients with Parkinson's disease (PD) have sentence comprehension difficulty, but it is unclear whether this is due to a deficit in grammatical processing or to an executive resource limitation. To assess grammatical processing in PD while minimizing task-related demands, PD patients and healthy control subjects performed a word detection procedure that assesses sensitivity to grammatical agreements in sentences in an "on-line" fashion. With this technique, we found that control subjects and PD patients are equally sensitive to grammatical agreement violations in sentences. A traditional, resource-demanding measure of sentence comprehension was also administered to the same PD patients. In comparison to healthy controls, PD patients were significantly impaired in their relative comprehension of sentences containing object-gap subordinate clauses compared to subject-gap subordinate clauses. Performance on several executive resource measures was also impaired in PD, and this correlated with their comprehension performance. Sensitivity to grammatical agreements with the word detection procedure, in the context of sentence comprehension difficulty on a traditional measure, suggests that PD patients' executive resource limitations contribute to their sentence comprehension difficulty.     

Underspecification of syntactic ambiguities: Evidence from self-paced reading

Syntactically ambiguous sentences are sometimes read faster than disambiguated strings. Models of parsing have explained this tendency by appealing either to a race in the construction of alternative structures or to reanalysis. However, it is also possible that readers of ambiguous sentences save time by strategically underspecifying interpretations of ambiguous attachments. In a self-paced reading study, participants viewed sentences with relative clauses that could attach to one of two sites. Type of question was also manipulated between participants in order to test whether goals can influence reading/parsing strategies. The experiment revealed an ambiguity advantage in reading times, but only when participants expected superficial comprehension questions. When participants expected queries about relative clause interpretation, disambiguating regions were inspected with more care, and the ambiguity advantage was attenuated. However, even when participants expected relative clause queries, question-answering times suggested underspecified representations of ambiguous relative clause attachments. The results support the construal and "good-enough" models of parsing.     

Sentential and discourse topic effects on lexical ambiguity processing: an eye movement examination

Models of lexical ambiguity resolution posit a role for context, but this construct has remained relatively undefined in the literature. The present study isolated two different forms of contextual constraint and examined how these sources of information might differentiate between a selective access and a reordered access model of ambiguity processing. Eye movements were monitored as participants read passages that contained either a balanced or a biased ambiguous word. The sentence containing the ambiguous word was held constant and instantiated either the subordinate meaning (Experiment 1) or the dominant meaning (Experiment 2) through the use of local context. These sentences were embedded in passages in which the topic was consistent, inconsistent, or neutral with respect to the meaning biased by the critical sentence. Experiment 1 provided evidence suggesting that the subordinate meaning of an ambiguous word was not selectively accessed even when sentence and discourse topic information biased that meaning. The data from Experiment 2 provided evidence that even the dominant meaning was not selectively accessed. These contextual sources of information were evaluated in terms of the roles they play in models of lexical ambiguity resolution.     

Semantic activation of noun concepts in context

A modified Stoop procedure was used to examine the role that context plays in guiding semantic access of unambiguous nouns in sentence contexts. The sentences either emphasized a high- or a low-dominant property of a noun that was the last word in the sentence or were control sentences. Each sentence was followed by the relevant high- or low-dominant property either immediately or after a 300-or 600-ms delay. There was significant color-naming interference (relative to control) for high-dominant properties regardless of biasing context in the immediate and delayed conditions. There was also significant color-naming interference for low-dominant properties in the immediate condition regardless of context. However, in the delayed conditions, the low-dominant properties led to color-naming interference only when preceded by sentence contexts biasing interpretation toward the low-dominant property. It was concluded that high-dominant properties function as core, or invariant, aspects of meaning and that initial semantic access is context independent.     

Influence of context on the activation and selection of ambiguous word senses

The activation of ambiguous word senses was investigated by measuring the amount of interference in naming the ink color of a word that was either related or unrelated to one of the meanings of a preceding ambiguous word. In agreement with previous results obtained using this procedure (Conrad, 1974), evidence was obtained that both meanings of the ambiguous words are activated even in the presence of biasing context. However, contrary to previous findings, the degree of activation of each word sense depended on its degree of compatibility with the context. These results are consistent with a language processing system in which all interpretations of an ambiguity are accessed and then processed until an accurate determination has been made of which interpretation best satisfies the syntactic and semantic constraints that govern it.     

无语境条件下汉语词类歧义词的意义激活

以单字词为实验材料,采用启动命名任务,在孤立词条件下考察了汉语词类歧义词不同意义激活的时间进程特点。实验发现,歧义词的两种意义都能被激活,但主要意义激活得较早,次要意义激活速度较慢;当两种意义都激活之后,次要意义的激活水平降低,而主要意义仍维持在一定激活水平。结果表明,汉语词类歧义词的多重激活过程会受到意义相对频率的影响。     

To end ambiguous sentences

A study of the time required to complete ambiguous sentences suggested that: even though Ss are unaware of the ambiguity while completing sentences, they take more time to complete ambiguous sentences than unambiguous ones: the degree of difficulty in completing ambiguous sentences is related to the linguistic level at which the ambiguity occurs: sentences containing two ambiguities are more difficult to complete than those containing only one, and when these two ambiguities occur at different linguistic levels, these sentences are harder to complete than when both occur within the same linguistic level: ambiguity may affect the grammaticality and relevance of completions; and may cause stuttering and laughter, even without awareness of the ambiguity. An attempt to fit these results to several theories of the processing of ambiguous sentences led us to the conclusion that ambiguity interferes with our understanding of a single meaning of a sentence, and that the degree of interference varies with the linguistic level at which the ambiguity occurs.     

The processing of metonymy: evidence from eye movements

The authors investigated the time course of the processing of metonymic expressions in comparison with literal ones in 2 eye-tracking experiments. Experiment 1 considered the processing of sentences containing place-for-institution metonymies such as the convent in That blasphemous woman had to answer to the convent; it was found that such expressions were of similar difficulty to sentences containing literal interpretations of the same expressions. In contrast, expressions without a relevant metonymic interpretation caused immediate difficulty. Experiment 2 found similar results for place-for-event metonymies such as A lot of Americans protested during Vietnam, except that the difficulty with expressions without a relevant metonymic interpretation was somewhat delayed. The authors argue that these findings are incompatible with models of figurative language processing in which either the literal sense is accessed first or the figurative sense is accessed first. Instead, they support an account in which both senses can be accessed immediately, perhaps through a single under-specified representation.