Biomedical subjects

G Kellas

Publications and source records attributed to G Kellas.

At least 19 recordsLinked to original sources

PubMed2000

The influence of global discourse on lexical ambiguity resolution.

The influence of global discourse on the resolution of lexical ambiguity was examined in a series of naming experiments. Two-sentence passages were constructed to bias either the dominant or the subordinate meaning of a homonym that was embedded in a locally ambiguous sentence. The results provided evidence for the immediate (0-msec interstimulus interval) resolution of lexical ambiguity and were subsequently replicated in Experiment 2, in which an 80-msec stimulus onset asynchrony exposure duration was employed for the homonyms. Strong dominant and subordinate biased discourse contexts activated only the contextually appropriate sense of a homonym. In Experiment 3, each sentence of the discourse was presented in isolation. The pattern of activation obtained in Experiments 1 and 2 was found to be contingent on the integration of the two sentences to construct an overall global discourse representation of the text. The results support a context-sensitive model of lexical ambiguity resolution.

Cognition↗

PubMed1999

Age and the allocation of attention across the time course of word recognition.

Younger and older adults performed lexical decisions on ambiguous words, unambiguous words, and pseudowords, and simultaneously responded to an auditory probe presented at stimulus onset asynchronies (SOAs) of 90, 180, or 270 ms. For both age groups, lexical decisions and probe responses were faster for ambiguous words than for unambiguous words, and slowest for pseudowords. For the older adults, but not the younger adults, lexical decisions were slower when the probe was presented (the dual-task condition), compared with a control condition in which the lexical decision was performed alone. The older participants also showed slower tone-detection responses in the dual-task condition than when the tone was presented alone. For all participants, proportional tone-detection times (compared with tones in isolation) decreased with increasing SOA, but this decrease was less pronounced in the older group. Finally, the time between responses in the dual-task condition was longer for older than for younger adults. The results indicate that word meaning influences the allocation of attention similarly for younger and older adults, but that older adults suffer a cost and become disproportionately slower in processes related to response coordination and output.

Adult↗

PubMed1999

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

Two experiments examined the influence of strength of discourse bias on lexical ambiguity resolution. Short passages were constructed to bias polarized ambiguous words (homonymous) strongly or weakly toward the dominant or subordinate meanings. Using a self-paced reading task in Experiment 1, it was demonstrated that in strongly biased discourse, reading times for homonyms in dominant discourse did not differ from those in subordinate discourse. However, when the discourse was weakly biased, homonyms were read faster in dominant discourse than in subordinate discourse. Experiment 2 combined the reading paradigm with a naming task in order to provide an assessment of specific word-meaning activation. Reading times on ambiguous words replicated the results of Experiment 1. In addition, naming latencies for probe words revealed that only the contextually appropriate sense of a homonym was activated in strongly biased discourse. In contrast, both contextually appropriate and inappropriate senses were activated following a weakly biased subordinate discourse, whereas only the dominant sense was activated following weakly biased dominant discourse. The results demonstrate (1) an immediate influence of prior discourse information on lexical processing; and (2) that the strength of discourse constraints can play a governing role in lexical ambiguity resolution. The results were interpreted within the framework of a context-sensitive model of lexical ambiguity resolution.

Humans↗

PubMed1999

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.

Cognition↗

PubMed1998

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.

Analysis of Variance↗

PubMed1992

Influence of contextual features on the activation of ambiguous word meanings.

Three studies examined whether initial meaning activation is sensitive to context. Experiment 1 demonstrated that contextually appropriate targets were activated more than inappropriate targets. Experiment 2 evaluated activation across intervals of 0, 300, and 600 ms. Constraining sentences activated contextually appropriate meanings over inappropriate meanings. This was maintained across the intervals for highly salient targets. Less-salient targets, although initially activated, were no longer activated 300 ms following the homograph. Experiment 3 converged on context-sensitive activation following a 50-ms exposure of the sentence-final homograph. Conclusions are (a) initial meaning activation can be sensitive to context, (b) when a homograph is instantiated, it is congruent with a broad scope of targets, and (c) less-salient targets receive less activation over the time course.

Adult↗

PubMed1992

Age-related changes in the effects of target orientation on word recognition.

Twenty-four undergraduates and 24 retired faculty participated in an experiment involving semantic priming of lexical decisions. Age-related differences in the use of semantic information during visual word recognition were examined at varying orientations of the target word. Four main results were found: (1) larger rotation effects for elderly adults; (2) larger priming effects for elderly adults; (3) larger priming effects with increasing Target Orientation; and (4) larger priming effects for the elderly adults as Target Orientation increased. Results are interpreted within an interactive-compensatory framework.

Adult↗

PubMed1988

Lexical ambiguity and the timecourse of attentional allocation in word recognition.

In two experiments the allocation of attention during the recognition of ambiguous and unambiguous words was investigated. In Experiment 1, separate groups performed either lexical decision, auditory probe detection, or their combination. In the combined condition probes occurred 90, 180, or 270 ms following the onset of the lexical-decision target. Lexical decisions and probe responses were fastest for ambiguous words, followed by unambiguous words and pseudowords, respectively, which indicated that processing ambiguous words was less attention demanding than unambiguous words or pseudowords. Attention demands decreased across the timecourse of word recognition for all stimulus types. In Experiment 2, one group performed the lexical-decision task alone, whereas another group performed the lexical-decision task during the retention interval of a short-term memory task. The results were consistent with those from Experiment 1 and showed that word recognition is an attention-demanding process and that the demands are inversely related to the number of meanings of the stimulus. These results are discussed with regard to the structure of the mental lexicon (i.e., single vs. multiple lexical entries) and the effect of such a structure on attentional mechanisms.

Attention↗

PubMed1985

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.

Attention↗

PubMed1984

Processing category terms in context: instantiation and the structure of semantic categories.

The present study sought to determine if semantic categories processed in context are encoded as particular exemplars. In Experiment 1 we replicated previous results on an extended and modified set of stimuli by showing that when subjects read sentences containing a category term in a context designed to bias encoding toward an atypical exemplar, the atypical exemplar serves as a better retrieval cue than a typical exemplar. In Experiment 2 we tested whether these cued-recall results were due to processes operating at encoding or retrieval. The pattern of semantic interference obtained in a modified Stroop paradigm clearly contradicted the position that readers routinely encode general terms as examples, or "instantiations." In particular, there was significant color-naming interference when typical exemplars served as targets even when preceded by sentences designed to bias encoding toward an atypical exemplar. No significant color-naming interference was generated to atypical exemplars. Experiment 3 ruled out the possibility that differences between the cued-recall and Stroop results in the first two experiments were due to encoding strategy differences. It was concluded that assigning a referent to a category term is not a routine activity in sentence encoding and that processing category terms entails activation of summary representations.

Adult↗

PubMed1981

False recognition of static and dynamic object properties by preschool children.

A false recognition task was used to compare preschool children's use of static and dynamic properties of objects in semantic processing. Four, five, and six year old children heard a list of object names, and then were tested for recognition of these words with a recognition test list that included distractor words that were static or dynamic properties of the objects on the first list. False recognition scores of dynamic properties were higher than those for static, for 4 and 5 year old children, with no differences for 6 year old children. The results argue for a functional basis for the encoding of referential terms in memory, and are discussed in terms of two models of semantic development.

Age Factors↗

PubMed1974