Spatial processing of spoken words in aphasia and in neglect.
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Two experiments were conducted to examine the importance of inhibitory abilities and semantic context to spoken word recognition in older and young adults. In Experiment 1, identification scores were obtained in 3 contexts: single words, low-predictability sentences, and high-predictability sentences. Additionally, identification performance was examined as a function of neighborhood density (number of items phonetically similar to a target word). Older adults had greater difficulty than young adults recognizing words with many neighbors (hard words). However, older adults also exhibited greater benefits as a result of adding contextual information. Individual differences in inhibitory abilities contributed significantly to recognition performance for lexically hard words but not for lexically easy words. The roles of inhibitory abilities and linguistic knowledge in explaining age-related impairments in spoken word recognition are discussed.
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Functional brain imaging studies with positron emission tomography (PET) have identified blood flow changes in widely separated areas of the brain during the performance of word-related tasks. In the present study, we have utilized event-related electrical potentials (ERPs) to investigate the temporal relationships among cortical areas previously identified by PET to be differentially activated when performing a task involving generating the uses of visually presented nouns versus reading aloud. ERPs showed strong task-related differences over left and middle inferior frontal and left parietotemporal regions. Frontal and left parietotemporal channels revealed these differences around 200 and 700 msec, respectively, after word presentation. These results provide the time course for parts of the anatomical circuit involved in generating the meaning of a word. Our results also demonstrate how combining the spatial localization of PET with the temporal resolution of ERPs greatly enhances the capacity to understand the mechanisms involved in human cognition.
There has been much debate about the role of phonology in reading. This debate has been fuelled, in part, by mixed findings for phonological effects in lexical decision tasks. In the present research we investigated the impact of reader skill on three phonological effects (homophone, homograph, and regularity effects) in a lexical decision task and in a phonological lexical decision task. In both tasks, the more skilled readers showed different patterns of phonological effects from those of the less skilled readers; in particular, less skilled readers showed regularity effects in both tasks whereas more skilled readers did not. We concluded that more skilled readers activate phonology in these tasks but do so more efficiently, with less spurious phonological activation.
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This study represents an attempt to determine the nature and efficiency of the strategies used by prelingually deafened individuals for the recognition of written words with reference to an orthographic self-teaching concept (D. L. Share, 1995). A research paradigm asking the participants to make categorical judgments for real words and pseudohomophones of the real words was used for gathering the data. Participants were prelingually deafened, native signers (n = 11, age = 14.18) and a hearing control group (n = 25, age = 15.00). In general, findings suggest that, although the participants with deafness were very impaired in their phonological decoding abilities, their efficiency in recognizing and categorizing written words was similar to that of their hearing counterparts. This suggests that they must have developed strategies for the acquisition of orthographic knowledge that do not rely on phonology.
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A number of behavioral studies have suggested that syllables might play an important role in visual word recognition in some languages. We report two event-related potential (ERP) experiments using a new paradigm showing that syllabic units modulate early ERP components. In Experiment 1, words and pseudowords were presented visually and colored so that there was a match or a mismatch between the syllable boundaries and the color boundaries. The results showed color-syllable congruency effects in the time window of the P200. Lexicality modulated the N400 amplitude, but no effects of this variable were obtained at the P200 window. In Experiment 2, high- and low-frequency words and pseudowords were presented in the congruent and incongruent conditions. The results again showed congruency effects at the P200 for low-frequency words and pseudowords, but not for high-frequency words. Lexicality and lexical frequency effects showed up at the N400 component. The results suggest a dissociation between syllabic and lexical effects with important consequences for models of visual word recognition.
A visual presentation procedure is introduced that presents target words followed by a dynamic mask until recognition. This form of stimulus degradation prolongs the word recognition process. Differences in word recognition latencies-which are usually quite small--are magnified, and thus can be more easily observed. The results of two experiments on the Internet with a total of 141 participants establish the task's ability to magnify differences in word recognition latencies stemming from word familiarity (Experiment 1) and word prototypicality (Experiment 2). Both factors interact with stimulus degradation, but at different presentation intervals; these results are discussed as evidence for comparing models of word recognition. The new procedure can be used for assessing individual differences, such as implicit motives and self-focused attention. Further applications are discussed.
Readers' eye movements were monitored as they read biased ambiguous target words in the context of a short paragraph. Two aspects of context were manipulated. The global context was presented in the topic sentence of the paragraph and instantiated either the dominant or the subordinate meaning of biased ambiguous target words (those with highly dominant meanings). Local contextual information either preceded or followed the target word and was always consistent with the subordinate interpretation. Consistent with prior research, we obtained a subordinate bias effect wherein readers looked longer at the ambiguous words than control words when the preceding context instantiated the subordinate meaning. More importantly, the magnitude of the subordinate bias effect was the same when global context alone, local context alone, or local and global context combined were consistent with the subordinate meaning of the ambiguous word. The results of this study indicate that global contextual information (1) has an immediate impact on lexical ambiguity resolution when no local disambiguating information is available, (2) has no additional effect when it is consistent with local information, but (3) does have a slightly delayed effect when inconsistent with local information.
Lexical decision to a target is typically facilitated when a related prime is simply read, but is typically eliminated if subjects carry out a letter search on the prime when probe and prime appear simultaneously. Three experiments involving the addition of a task-irrelevant word to this prime search paradigm address (1) Stolz and Besner's (1996, 1998) account in which semantic priming is eliminated because letter search on the prime instantiates an activation block between lexical and semantic levels of representation, (2) Chiappe, Smith, and Besner's (1996) account that activation blocking is domain specific, and (3) Neely and Kahan's (2001) claim that semantic activation is context independent and capacity free. The results are (1) consistent with the account that activation blocking is general to a level, rather than item specific, (2) consistent with the account that activation blocking is domain specific, and (3) inconsistent with the claim that semantic activation is context independent and capacity free.
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Relations between phonological processing abilities and word-level reading skills were examined in a longitudinal correlational study of 216 children. Phonological processing abilities, word-level reading skills, and vocabulary were assessed annually from kindergarten through 4th grade, as the children developed from beginning to skilled readers. Individual differences in phonological awareness were related to subsequent individual differences in word-level reading for every time period examined. Individual differences in serial naming and vocabulary were related to subsequent individual differences in word-level reading initially, but these relations faded with development. Individual differences in letter-name knowledge were related to subsequent individual differences in phonological awareness and serial naming, but there were no relations between individual differences in word-level reading and any subsequent phonological processing ability.
In the present study, the author explored the effect of processing relevant information on producing solutions to brief insight problems. She hypothesized that the conceptual processing of objects relevant to the target solution would facilitate that solution relative to unrelated objects or the shallow processing of words. The author also explored the effect of knowledge of the relationship between the initial object-processing task and the problem-solving task. The results showed that participants who conceptually processed objects related to the target solution (Experiment 1), but not those who shallowly processed words related to the target solution (Experiment 2), were more likely to produce the solution relative to the control; and knowledge of the relationship between objects and solutions made no difference in the frequency of target solutions produced. The results of Experiment 3 showed that conceptual processing of an object could prime a nondominant solution for an ambiguously worded problem. Taken together, the results of the studies supported the effect of conceptual processing on facilitating insight in problem solving.
The purpose of this study was to delineate the neural pathways involved in processing concrete and abstract words using functional magnetic resonance imaging (fMRI). Word and pseudoword stimuli were presented visually, one at a time, and the participant was required to make a lexical decision. Lexical decision epochs alternated with a resting baseline. In each lexical decision epoch, the stimuli were either concrete words and pseudowords, or abstract words and pseudowords. Behavioral data indicated that, as with previous research, concrete word stimuli were processed more efficiently than abstract word stimuli. Analysis of the fMRI data indicated that processing of word stimuli, compared to the baseline condition, was associated with neural activation in the bilateral fusiform gyrus, anterior cingulate, left middle temporal gyrus, right posterior superior temporal gyrus, and left and right inferior frontal gyrus. A direct comparison between the abstract and concrete stimuli epochs yielded a significant area of activation in the right anterior temporal cortex. The results are consistent with recent positron emission tomography work showing right hemisphere activation during processing of abstract representations of language. The results are interpreted as support for a right hemisphere neural pathway in the processing of abstract word representations.