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.

The present study investigated the scope of planning in speech production by examining onset latencies for sentences describing moving picture displays. The experimental sentences began with either a simple or complex noun phrase, but were matched in length and content words. Results from young and old normal participants replicated previous findings of Smith and Wheeldon (1999) in showing longer onset latencies for sentences beginning with a complex noun phrase, supporting a phrasal scope of planning. Two aphasic patients were tested who, in previous studies, had shown a short-term memory deficit either in semantic retention (patient ML)or in phonological retention (patient EA). Patient ML showed a markedly greater disadvantage for the sentences beginning with a complex noun phrase whereas EAshowed an effect within normal range. The present results from the patients, together with those from previous studies, indicate that the phrasal planning is occurring at a lexical-semantic level using a capacity that is also involved in comprehension.

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 (O-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.Over the past two decades, lexical ambiguity research has sustained a theoretical dichotomy in which the processing of an ambiguous word (e.g., a homonym) is either influenced by context or impervious to it. The bulk of the research on whether context can immediately influence lexical ambiguity resolution has produced mixed results. Early studies supported the principles of modularity (see Fodor, 1983;Forster, 1979), in which the process ofword meaning activation is encapsulated and independent ofhigher level influences ofsyntax and semantics (e.g., Onifer & Swinney, 1981; Seidenberg, Tanenhaus, Leiman, & Bienkowski, 1982;Swinney, 1979). For example, Swinney presented passages aurally, each of which contained an ambiguous word, and found that lexical decision times for both contextually appropriate and inappropriate target words were faster than those for unrelated words. Seidenberg et al. (1982) also employed the crossmodal priming paradigm, but used a naming task as an index ofpriming, and found that naming latencies for target words that were related to the dominant and subordinate meanings of words with noun/verb ambiguities were faster than those for unrelated target words.More recent research has presented a challenge for the modular view of ambiguity resolution. Several studies have supported an interactive activation framework (see Marslen-Wilson & Tyler, 1987;McClelland, 1987), in which context can immediately influence meaning activation in such a way that only the contextually appropriate meaning of an ambiguous word is activated (e.g

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.

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.

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Using a self-paced reading task, KeUas, Martin, Yehling, Herman, and Vu (1995) Research on lexical ambiguity resolution has demonstrated that the activation of word meanings can be markedly influenced by the variables of meaning frequency (cf. Hogaboam & Perfetti, 1975) and biasing context (e.g., Paul, Kellas, Martin, & Clark, 1992;Tabossi, Colombo, & Job, 1987;Van Petten & Kutas, 1987). This has led to an investigation of the relationship between meaning frequency and contextual bias (e.g., Duffy, Morris, & Rayner, 1988;Rayner, Pacht, & Duffy, 1994;Simpson, 1981;Simpson & Krueger, 1991;Vu, Kellas, & Paul, 1998) and to the proposal of the reordered access and the context-sensitive models of lexical ambiguity resolution.Introduced by Duffy et al. (1988), the reordered access model assumes an exhaustive retrieval of the meanings of an ambiguous word (e.g., a homonym) in all contexts. The meanings are accessed in the order of frequency with which each sense is given as an associative response inWe thank Greg Simpson for his help on an earlier draft of this manuscript. Correspondence concerning this article should be addressed to G. Kellas, Department of Psychology, University of Kansas, Lawrence, KS 66045 (e-mail: gkellas@lark.cc.ukans.edu). norming studies. Biasing context can reorder the availability of the meanings by boosting activation of the contextually appropriate sense, but it cannot preclude the inappropriate meaning( s) from being accessed. Results from eye-tracking measures have demonstrated two consistent findings. First, when biasing context precedes a balanced homonym (equal frequency of dominant and subordinate meanings), or when the preceding context biases the dominant sense of a polarized homonym (the most frequent meaning), reading time on the ambiguous word is comparable with that on an unambiguous control word. Although all the meanings are initially available, the appropriate meaning is quickly integrated with the context, because there is no competition with the less activated inappropriate meanings. Second, when the preceding context is biased toward the subordinate meaning of a polarized homonym, reading time is longer, relative to the control word. This outcome is referred to as the subordinate bias effect (SBE) and is assumed to reflect a time-consuming competition for text integration between two equally available meanings (the dominant sense, because of meaning frequency, and the subordinate sense, because of context).The context-sensitive model recognizes the importance of meaning frequency and biasing context, but it is the parameter ofcontext strength that will determine the pattern of meaning activation (cf. Vu et aI., 1998). According to the context-sensitive position, a balanced homonym preceded by biasing context or a polarized homonym preceded by a dominant-biased context will lead to the activation of only the dominant meaning of the ambiguous word. However, when a polarized homonym is preceded by a subordinate-biased context, there are two possible outcomes. The SBE may em...

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.