Crystal structure of human serum albumin complexed with fatty acid reveals an asymmetric distribution of binding sites

A lexical decision experiment investigated hemisphere asymmetries in resolving lexical ambiguity within a sentence context. Sentences that biased a single meaning (either dominant or subordinate) of sentence-final ambiguous words were followed by a lateralized target related to the sentence-congruent or -incongruent meaning of the ambiguous word, or an unrelated word. In the RVF sentence-congruent targets were facilitated, while incongruent targets were not primed. In contrast, related targets were facilitated in the LVF, regardless of sentence context. This suggests that selecting the contextually appropriate word meaning requires the left hemisphere, and supports a right hemisphere role in maintaining alternate word senses.     

Phonological codes are used to access the lexicon during silent reading.

Readers' eye movements were monitored as they read sentences containing 1 member of a homophonic heterograph pair (e.g., soul-sole) or an unambiguous frequency- and length-matched control word. Prior context was either semantically neutral (Experiment 1) or semantically biasing (Experiment 2). The meaning dominance and word frequency of the heterographic targets were manipulated such that half were balanced and half were biased, and half were high frequency and half were low frequency. The processing pattern for both high- and low-frequency heterographs mirrored the pattern commonly observed for lexically ambiguous words. These findings are consistent with models of word recognition in which phonological codes activate word meaning for both high- and low-frequency words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading homographs: Orthographic, phonologic, and semantic dynamics.

Reading processes were compared across 3 word types: homographs (separate pronunciations and meanings, such as lead), homonyms (singular pronunciations but separate meanings, such as spring), and control words (e.g., clock). In Experiment 1, naming reaction times were significantly slower to homographs than to all other words. Experiments 2 and 3 used an association judgment task, with referent words related to the dominant or subordinate meanings of homonyms and homographs. In Experiment 2, homonyms and homographs were presented 1st, followed by disambiguating associates. In Experiment 3, presentation order was reversed. For homographs, performance costs always occurred for subordinate meanings. For homonyms, these costs vanished when context was provided by the preceding associates. The data underscore the priority of phonologic information in word meaning access and suggest that low- and high-level constraints combine to shape word perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Resolution of lexical ambiguity: Evidence from an eye movement priming paradigm.

Subjects' eye movements were monitored while they read 2-sentence passages of text. A target-word region was defined in the 2nd sentence of each passage. During the initial 35 ms of a target region eye fixation, an ambiguous word was presented as a prime. A target word subsequently replaced the prime during the fixation. Priming was measured by comparing fixation times on targets preceded by semantically related versus unrelated ambiguous primes. The type of prior context (consistent vs. inconsistent), type of ambiguous prime (biased vs. balanced), and strength of instantiated meaning (dominant vs. subordinate) could all affect priming. Priming effects were only found when the prior context was consistent with the dominant sense of a biased ambiguous prime. The results are discussed in terms of models of ambiguity resolution: The data seem most consistent with a reordered access model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements and lexical ambiguity resolution: Investigating the subordinate-bias effect.

Recent debates on lexical ambiguity resolution have centered on the subordinate-bias effect, in which reading time is longer on a biased ambiguous word in a subordinate-biasing context than on a control word. The nature of the control word--namely, whether it matched the frequency of the ambiguous word's overall word form or its contextually instantiated word meaning (a higher or lower frequency word, respectively)--was examined. In addition, contexts that were singularly supportive of the ambiguous word's subordinate meaning were used. Eye movements were recorded as participants read contextually biasing passages that contained an ambiguous word target or a word-form or word-meaning control. A comparison of fixation times on the 2 control words revealed a significant effect of word frequency. Fixation times on the ambiguous word generally fell between those on the 2 controls and were significantly different than both. Results are discussed in relation to the reordered access model, in which both meaning frequency and prior context affect access procedures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical ambiguity resolution in good and poor comprehenders: An eye fixation and self-paced reading study in primary school children.

To investigate the use of context and monitoring of comprehension in lexical ambiguity resolution in children, the authors asked 10- to 12-year-old good and poor comprehenders to read sentences consisting of 2 clauses, 1 containing the ambiguous word and the other the disambiguating information. The order of the clauses was reversed so that disambiguating information either preceded or followed the ambiguous word. Context use and comprehension monitoring were examined by measuring eye fixations (Experiment 1) and self-paced reading times (Experiment 2) on the ambiguous word and disambiguating region. The results of Experiment 1 and 2 showed that poor comprehenders made use of prior context to facilitate lexical ambiguity resolution as effectively as good comprehenders but that they monitored their comprehension less effectively than good comprehenders. Good comprehenders corrected an initial interpretation error on an ambiguous word and restored comprehension once they encountered the disambiguating region. Poor comprehenders failed to deal with this type of comprehension failure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sources of sentence constraint on lexical ambiguity resolution

Results from a series of naming experiments demonstrated that major lexical categories of simple sentences can provide sources of constraint on the interpretation of ambiguous words (homonyms). Manipulation of verb (Experiment 1) or subject noun (Experiment 2) specificity produced contexts that were empirically rated as being strongly biased or ambiguous. Priming was demonstrated for target words related to both senses of a homonym following ambiguous sentences, but only contextually appropriate target words were primed following strongly biased dominant or subordinate sentences. Experiment 3 showed an increase in the magnitude of priming when multiple constraints on activation converged. Experiments 4 and 5 eliminated combinatorial intralexical priming as an alternative explanation. Instead, it was demonstrated that each constraint was influential only insofar as it contributed to the overall semantic representation of the sentence. When the multiple sources of constraint were retained but the sentence-level representation was changed (Experiment 4) or eliminated (Experiment 5), the results of Experiments 1, 2, and 3 and were not replicated. Experiment 6 examined the issue of homonym exposure duration by using an 80-msec stimulus onset asynchrony. The results replicated the previous experiments. The overall evidence indicates that a sentence context can be made strongly and immediately constraining by the inclusion of specific fillers for salient lexical categories. The results are discussed within a constraint-based, context-sensitive model of lexical ambiguity resolution.     

Activation and selection processes in the recognition of ambiguous words.

Three experiments with 234 undergraduates investigated the role of meaning frequency in the processing of ambiguous words in isolation. Ss made lexical decisions to target words that were associates of the more frequent or less frequent meaning of a homograph prime. Exps I–II charted the time course of activation of the 2 meanings, showing that the dominant meaning was retrieved first, with the subordinate meaning activated more slowly. Subsequent to its retrieval, activation of the less frequent meaning decreased again. Exp III indicated that meaning selection was the result of allocation of attention to information related to the dominant meaning of the ambiguous word. Overall results suggest the selection process is active but difficult for the S to control and that the processing of ambiguous words in isolation may be conceived of as a 2-stage process: automatic selection followed by a 2nd, optional stage driven by the deliberate allocation of limited-capacity resources. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements and lexical ambiguity resolution: Effects of prior encounter and discourse topic.

Eye movements were monitored as participants read passages that contained 2 occurrences of a balanced ambiguous word. In Experiment 1, local context was manipulated so that the meaning of the ambiguous word either remained the same or changed from the 1st to 2nd encounter. In Experiments 2 and 3, global context was manipulated by shifting the discourse topic between the 2 instances of the ambiguous word. Gaze durations on the 2nd instance of the ambiguous word were shorter when the meaning remained consistent than when the meaning changed, and this facilitation was impervious to changes in the discourse structure. In contrast, processing time in the region immediately following the target was longer when the word meaning changed, but only when the topic of the discourse remained the same throughout the passage. When the topic was shifted, this effect disappeared. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The time-limited influence of sentential context of function word identification.

Sentential context effects on the identification of the Dutch function words te (to) and de (the) were examined. In Experiment 1, listeners labeled words on a [te]–[de] continuum more often as to when the context was to biased (Ik probeer [?e] schieten [I try to/the shoot]) than when it was de biased (Ik probeer [?e] schoenen [I try to/the shoes]). The effect was weaker in slower responses. In Experiment 2, disambiguation began later, in the second word after [?e]. There was a weak context effect only in the slower responses. In Experiments 3 and 4, disambiguation occurred on the word before [?e]: There was no context effect when one set of sentences was used, but there was an effect (larger in the faster responses) when more sentences were used. Syntactic processing affects word identification only within a limited time frame. It appears to do so not by influencing lexical access processes through feedback but, instead, by biasing decision making. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bihemispheric processing of redundant bilateral lexical information

Cerebral asymmetries in lexical ambiguity resolution were studied. In 2 experiments, targets related to the dominant and subordinate meanings of ambiguous word primes were presented for lexical decision after a 750-ms stimulus onset asynchrony. Experiment 1 compared presentation of target words to the left visual field/right-hemisphere (LVF/RH), to the right visual field/left-hemisphere (RVF/LH), or after redundant bilateral visual field (BVF) presentation. Experiment 2 examined unilateral priming in the absence of a BVF condition. On unilateral trials, priming was observed for dominant meanings in both the LVF/RH and RVF/LH, whereas subordinate priming was obtained only in the RVF/LH. These results suggest a possible role of hemispheric interaction in the availability of ambiguous word meanings. BVF performance evidenced a bilateral redundancy gain and priming that resembled that obtained on RVF/LH trials. Additional BVF analyses were not consistent with a strict race model interpretation and appear to implicate hemispheric cooperation in the bihemisperic processing of lexical information.     

Reading Finnish compound words: eye fixations are affected by component morphemes

The role of morphemic processing in reading was investigated in 2 experiments in which participants read sentences as their eye movements were monitored. The target words were 2-morpheme Finnish compound words. In Experiment 1, the length of the component morphemes was varied and word length was held constant, and in Experiment 2, the uniqueness of the initial morpheme was varied and the rated familiarity and length of the word were held constant. The length of the initial morpheme influenced the location of the second fixation on the target word and the pattern of fixation durations (although it had a negligible influence on the gaze duration of the word). The frequency of the initial morpheme influenced the duration of the first fixation on the target word, had a substantial effect on the gaze duration, and also influenced the location of the first and second fixations on the target word. Subsidiary analyses indicated that these effects were unlikely to stem from orthographic factors such as bigram frequency.     

Scope of word meaning activation during sentence processing by young and older adults

In a naming experiment, we examined word meaning activation on-line during sentence processing by younger and older adults. Sentences were biased to either the most or least frequently used meaning of a sentence-final ambiguous word. In order to determine the scope of initial meaning activation, targets represented either high- or low-salient semantic relationships to a single sense of the ambiguous word in context. Both age groups evidenced context-dependent activation of word meaning. In addition, context activated a wide scope of meaning that included both high- and low-salience aspects of the ambiguous words. These results contradict predictions based on the inhibition deficit hypothesis (Hasher & Zacks, 1988). However, they are compatible with an interactive activation model of language comprehension that does not discriminate among age groups.     

Lexical and message-level sentence context effects on fixation times in reading.

Readers' eye movements were recorded as they read an unambiguous noun in a sentence context. In Exp 1, fixation durations on a target noun were shorter when it was embedded in context containing a subject noun and a verb that were weakly related to the target than when either content word was replaced with a more neutral word. These results were not affected by changes in the syntactic relations between the content words. In Exp 2, the semantic relations between the message-level representation of the sentence and the target word were altered whereas the lexical content was held constant. Fixation time on the target word was shorter when the context was semantically related to the target word than when it was unrelated. Intralexical priming effects between the subject noun and the verb were also observed. Results suggest that both lexical and message-level representations can influence the access of an individual lexical item in a sentence context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric differences in context sensitivity during lexical ambiguity resolution

Three experiments were conducted to investigate the influence of contextual constraint on lexical ambiguity resolution in the cerebral hemispheres. A cross-modal priming variant of the divided visual field task was utilized in which subjects heard sentences containing homonyms and made lexical decisions to targets semantically related to dominant and subordinate meanings. Experiment 1 showed priming in both hemispheres of dominant meanings for homonyms embedded in neutral sentence contexts. Experiment 2 showed priming in both hemispheres of dominant and subordinate meanings for homonyms embedded in sentence contexts that biased a central semantic feature of the subordinate meaning. Experiment 3 showed priming of dominant meanings in the left hemisphere (LH), and priming of the subordinate meaning in the right hemisphere (RH) for homonyms embedded in sentences that biased a peripheral semantic feature of the subordinate meaning. These results are consistent with a context-sensitive model of language processing that incorporates differential sensitivity to semantic relationships in the cerebral hemispheres.     

Learning new word meanings from context: A study of eye movements.

This study examined how readers establish the meaning of a new word from the sentence context during silent reading. Readers' eye movements were monitored while they read pairs of sentences containing a target word, context, and a word related to the target word. The target word varied in familiarity (high, low, or novel). The context varied in informativeness about the meaning of the target word (informative or neutral). The amount of time readers spent on the context depended on both the familiarity of the target word and the informativeness of the context. Readers spent additional time on the related word only when the context was neutral and the target was novel. These results indicate that readers were able to determine which areas of text were relevant and used the information to infer a meaning for the novel word. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements and word skipping during reading: Effects of word length and predictability.

Eye movements were monitored as subjects read sentences containing high- or low-predictable target words. The extent to which target words were predictable from prior context was varied: Half of the target words were predictable, and the other half were unpredictable. In addition, the length of the target word varied: The target words were short (4–6 letters), medium (7–9 letters), or long (10–12 letters). Length and predictability both yielded strong effects on the probability of skipping the target words and on the amount of time readers fixated the target words (when they were not skipped). However, there was no interaction in any of the measures examined for either skipping or fixation time. The results demonstrate that word predictability (due to contextual constraint) and word length have strong and independent influences on word skipping and fixation durations. Furthermore, because the long words extended beyond the word identification span, the data indicate that skipping can occur on the basis of partial information in relation to word identity. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Salience and awareness in the Jacoby-Whitehouse effect.

L. L. Jacoby and K. Whitehouse (1989) observed that false recognition of new test words was biased by the nature and duration of preceding context words. With very brief exposures to context words, participants were more likely to call a test item "old" when the prior context word was identical than when there was a mismatch. At longer durations, the reverse pattern was obtained. In the present experiment, test items were preceded by the rapid visual presentation of 7 supraliminal context items, 1 of which might or might not match the test item. Participants either looked for matches (high salience) or tried to remember the context items (low salience). The results closely resemble those for long and short exposure durations, suggesting that the crucial variable is the salience of matches rather than perceptual subliminality of context items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Context and lexical access: Implications of nonword interference for lexical ambiguity resolution.

To eliminate potential "backward" priming effects, S. Glucksberg et al (see record 1986-29080-001) 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 judgments of the congruence of the sentence context and the target, not to context constraining lexical access. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory-based processing as a mechanism of automaticity in text comprehension.

A widespread theoretical assumption is that many processes involved in text comprehension are automatic, with automaticity typically defined in terms of properties (e.g., speed, effort). In contrast, the authors advocate for conceptualization of automaticity in terms of underlying cognitive mechanisms and evaluate one prominent account, the memory-based processing account, which states that one mechanism underlying automatization involves a shift from algorithm-based interpretation of stimuli to retrieval of prior interpretations of those stimuli. During practice, participants repeatedly read short stories containing novel conceptual combinations that were disambiguated with either their dominant or subordinate meaning. During transfer, the combinations were embedded in new sentences that either preserved or changed the disambiguated meaning. The primary dependent variable was reading time in the disambiguating region of target sentences. Supporting the memory-based processing account, speed-ups with practice were larger for repeated versus unrepeated items of the same type, reading times for subordinate versus dominant meanings of the combinations converged on later trials, and practiced meanings were retrieved when items appeared in a transfer context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)