Semantic, repetition and rime priming between spoken words: behavioral and electrophysiological evidence

Semantic, phonological and repetition priming for auditorily presented words were examined, using both behavioral reaction times (RTs) and electrophysiological event-related potentials (ERPs) measures. On critical trials, a word prime was followed by a word target that was semantically or phonologically related (rime) or not related (control) to the prime. Pairs of word-pseudoword items served as fillers. Participants were asked to respond to word targets in the RT experiment and to pseudowords in the ERP experiment. In each experiment stimuli were presented once and then repeated in the very same way. RTs were found to be fastest for semantic, intermediate for rime and slowest for control targets; large repetition effects occurred for all targets. ERPs results showed that both semantic and phonological priming influenced the same component, namely the N400, whose amplitude was smallest to semantic, intermediate to rime and largest to control targets; repetition effects were only found for semantic trials.     

Effects of age and Alzheimer's disease on recognition of gated spoken words

This study investigated the effects of normal aging and Alzheimer's disease on listeners' ability to recognize gated spoken words. Groups of healthy young adults, healthy older adults, and adults with Alzheimer's disease were presented isolated gated spoken words. Theoretical predictions of the Cohort model of spoken word recognition (Marslen-Wilson, 1984) were tested, employing both between-group and within-group comparisons. The findings for the young adults supported the Cohort model's predictions. The findings for the older adult groups revealed different effects for age and disease. These results are interpreted in relation to the theoretical predictions, the findings of previous gating studies, and differentiating age from disease-related changes in spoken word recognition.     

Semantic priming between spoken words in adults and children.

Used an auditory lexical decision paradigm to determine occurrence of semantic priming between spoken words and to investigate the organization of the mental lexicon in preliterate children. 30 undergraduates and 24 1st-grade children (aged 6 yrs 2 mo to 7 yrs) were tested on a lexical decision task in which Ss had to decide whether pairs of spoken items were words. In both groups, significant facilitation was found for semantically related words compared with unrelated ones. Results indicate that semantic priming occurred in the auditory modality. The fact that children benefited at least as much from and often more than adults from an appropriate semantic context suggests that the lexicon of the child is organized in the same way as the adult's as early as 6 to 7 yrs of age. (French abstract) (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic processing and memory for attended and unattended words in dichotic listening: Behavioral and electrophysiological evidence.

Thirty-two Ss studied words presented to 1 ear, while ignoring a concurrent word list presented to the opposite ear. The N400 component of the event-related potentials elicited by attended words was modulated by semantic priming between successive words. The N400 elicited by unattended words was insensitive to semantic manipulation. Recognition memory was better for attended than for unattended words. However, the percentage of false positives was elevated equally for lures that were semantically related to "old" words, whether they had been attended or unattended. Words that were initially attended induced similar repetition effects in a lexical decision task as words that were initially unattended. Hence, both attended and unattended words are semantically processed and activate semantic representations. However, attended words form traces that are subsequently more available to conscious recollection than unattended words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonological and orthographic processing of Hebrew words: electrophysiological aspects

Brain activity among 15 male, college-level, normal readers in Israel was examined during phonological and orthographic word-recognition tasks. Both electrophysiological (event-related potentials, or ERPs) and behavioral measures were obtained. Data indicated that (a) behavioral accuracy was almost perfect for all the experimental tasks, and (b) although P200 and N400 ERP components were elicited in the experimental tasks, the latencies of those components were significantly longer and their amplitudes significantly higher in the phonological task. Variations in vowel information had no effect on word recognition in either type of task. The results suggest that among skilled readers of Hebrew, phonological processing during word recognition may be more effortful and may demand greater cognitive resources than orthographic processing. Furthermore, the additional phonological information represented in vowels appears to contribute little to word recognition in this population. These findings support earlier research on skilled reading in Hebrew as well as current theoretical models of reading.     

Semantic processing of previews within compound words.

Previous studies have suggested that previews of words prior to fixation can be processed orthographically, but not semantically, during reading of sentences (K. Rayner, D. A. Balota, & A. Pollatsek, 1986). The present study tested whether semantic processing of previews can occur within words. The preview of the second constituent of 2-constituent Finnish compound nouns was manipulated. The previews were either identical to the 2nd constituent or they were incorrect in the form of a semantically related word, a semantically unrelated word, or a semantically meaningless nonword. The results indicate that previews of 2nd constituents within compound words can be semantically processed. The results have important implications for understanding the nature of preview and compound word processing. These issues are crucial to developing comprehensive models of eye-movement control and word recognition during reading. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic memory in Alzheimer's disease.

Patients with Alzheimer's disease have been suggested to have a semantic memory impairment not present in the normal old. This article reviews the performance of Alzheimer patients on tests of various aspects of semantic memory, including word finding, knowledge of the semantic attributes, and associates of concepts, as well as their category membership. The effect that semantic context has on cognitive processes such as lexical and semantic priming and memory encoding is also reviewed. Finally, the ability of theoretical constructs such as implicit memory and automaticity to explain intertask variability in Alzheimer patients' semantic performance is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competition in spoken word recognition: Spotting words in other words.

Although word boundaries are rarely clearly marked, listeners can rapidly recognize the individual words of spoken sentences. Some theories explain this in terms of competition between multiply activated lexical hypotheses; others invoke sensitivity to prosodic structure. A connectionist model, SHORTLIST, is described, in which recognition by activation and competition is successful with a realistically sized lexicon. Three experiments are then reported in which listeners detected real words embedded in nonsense strings, some of which were themselves the onsets of longer words. Effects both of competition between words and of prosodic structure were observed, suggesting that activation and competition alone are not sufficient to explain word recognition in continuous speech. However, the results can be accounted for by a version of SHORTLIST that is sensitive to prosodic structure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic space in Alzheimer's disease patients.

A within-category sorting task was used to investigate conceptual relations from 2 semantic categories (animals and occupations) in mild and moderately impaired Alzheimer's disease (AD) patients. A multidimensional scaling analysis was applied to the data. The resulting 2-dimensional solutions indicated that mildly affected AD patients sorted within-category terms in a manner largely consistent with controls' performance but were less consistent in their application of domain knowledge. Moderate AD patients' solutions were less similar to controls' solutions. Mild AD patients' explanations of their sorting schemes were similar to those given by controls but less focused. Together these findings suggest that attribute knowledge may remain largely accessible in mild AD; however a deficiency in recruiting reflective processes in the service of task-related goals may limit the selective application of this information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Repetition of single words and nonwords in Alzheimer's disease

Repetition of single words and pronounceable nonwords (pseudowords) was assessed in Alzheimer's Disease (AD) patients to evaluate how lexical phonological processing might be accomplished when semantic and conceptual knowledge is impaired. AD patients performed significantly worse than healthy elderly controls on all repetition tasks. However, repetition abilities and dementia severity were not correlated, and AD patients produced the same distribution of error types as controls. Furthermore, despite their semantic problems, AD patients, like controls, showed a significant advantage for repeating real words compared to pseudowords, even when repeating low frequency phonologically complex words whose meaning is not likely to have been retained. The results support the postulated existence of a lexical phonological system that is used to repeat both known and novel words and that processes linguistic information independent of its meaning.     

Semantic memory in Alzheimer's disease and the frontotemporal dementias: A longitudinal study of 236 patients.

Using semantic dementia (SD) as a reference point, the authors assessed semantic memory in four other neurodegenerative disorders: progressive nonfluent aphasia (PNFA), frontal variant frontotemporal dementia (fvFTD), Alzheimer's disease (AD), and posterior cortical atrophy (PCA). Individuals with SD were more impaired than other groups on semantic measures and showed a characteristic pattern across tasks: category fluency (CF) worse than letter fluency (LF), naming worse than comprehension, and visual and verbal comprehension equally affected, suggesting disruption to an amodal semantic system. Individuals with AD demonstrated a similar pattern to a milder degree. Although PNFA, fvFTD, and PCA groups had abnormal scores (relative to controls) on most semantic measures, their differing patterns across measures indicate that the apparent semantic impairment in these conditions is largely secondary to other factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming the visual recognition of spoken words

A preliminary investigation was conducted to understand the effects of word visibility and prime association factors on visual spoken word recognition in lipreading, using a related/ unrelated prime-target paradigm. Prime-target pairings were determined on the basis of paper-and-pencil word associations completed by 85 participants with normal hearing. Spoken targets included 60 single-syllable Modified Rhyme Test words, prerecorded on laser video disc. Participants included 20 individuals with normal hearing and at least average lipreading skill for sentence-length materials. In related prime-target pairings, more targets with a high prime association were identified than with a low prime association. In unrelated prime-target pairings, a larger number of more-visible than less-visible targets was correctly identified. Individual participant differences were not statistically significant. Results from the present study suggest implications for models of visual spoken word recognition.     

Accessing spoken words: The importance of word onsets.

Approaches to spoken word recognition differ in the importance they assign to word onsets during lexical access. This research contrasted the hypothesis that lexical access is strongly directional with the hypothesis that word onsets are less important than the overall goodness of fit between input and lexical form. A cross-modal priming technique was used to investigate the extent to which a rhyme prime (a prime that differs only in its first segment from the word that is semantically associated with the visual probe) is as effective a prime as the original word itself. Earlier research had shown that partial primes that matched from word onset were very effective cross-modal primes. The present results show that, irrespective of whether the rhyme prime was a real word or not, and irrespective of the amount of overlap between the rhyme prime and the original word, the rhymes are much less effective primes than the full word. In fact, no overall priming effect could be detected at all except under conditions in which the competitor environment was very sparse. This suggests that word onsets do have a special status in the lexical access of spoken words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activation of embedded words in spoken word recognition.

Three cross-modal associative priming experiments investigated whether speech input activates words that are embedded in other words. When the embedded word corresponded to the final syllable of a bisyllabic carrier (boos, meaning angry embedded in framboos, meaning raspberry), facilitatory priming effects were observed for related targets of the embedded word. No effects were found when the end-embedded word did not start at the onset of a syllable (wijn meaning wine in zwijn meaning swine). Beginning-embedded words were activated only If the carrier was a nonword (vel meaning skin in velk), but not when the carrier was a word (vel in velg, meaning rim). The results support the joint operation of metric segmentation and lexical competition: Words are activated if their onset matches the onset of a strong syllable; words are then excluded on the basis of interword competition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

False recognition of pictures versus words in Alzheimer's disease: The distinctiveness heuristic.

False recognition of semantic associates can be reduced when older adults also study pictures representing each associate. D. L. Schacter, L. Israel, and C. Racine (1999) attributed this reduction to the operation of a distinctiveness heuristic: a response mode in which participants demand access to detailed recollections to support a positive recognition decision. The authors examined patients with probable Alzheimer's disease (AD) and older adults with this paradigm. Half of the participants studied pictures and auditory words; the other half studied visual and auditory words. Older adults who studied pictures were able to reduce their false alarms compared with those who studied words only. AD patients who studied pictures were unable to reduce their false alarms compared with those who studied words only and, in fact, exhibited trends toward greater false recognition. Implications for understanding semantic memory in AD patients are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic networks for odors and colors in Alzheimer's disease.

Objective: Impairment in odor-naming ability and in verbal and visual semantic networks raised the hypothesis of a breakdown in the semantic network for odors in Alzheimer's disease (AD). The current study addressed this hypothesis. Method: Twenty-four individuals, half patients with probable AD and half control participants, performed triadic-similarity judgments for odors and colors, separately, which, utilizing the multidimensional scaling (MDS) technique of individual difference scaling analysis (INDSCAL), generated two-dimensional configurations of similarity. The abilities to match odors and colors with written name labels were assessed to investigate disease-related differences in ability to identify and conceptualize the stimuli. In addition, responses on attribute-sorting tasks, requiring the odor and color perceptions to be categorized as one polarity of a certain dimension, were obtained to allow for objective interpretation of the MDS spatial maps. Results: Whereas comparison subjects generated spatial maps based predominantly on relatively abstract characteristics, patients with AD classified odors on perceptual characteristics. The maps for patients with AD also showed disorganized groupings and loose associations between odors. Their normal configurations for colors imply that the patients were able to comprehend the task per se. The data for label matching and for attribute sorting provide further evidence for a disturbance in semantic odor memory in AD. The patients performed poorer than controls on both these odor tasks, implying that the ability to identify and/or conceptualize odors is impaired in AD. Conclusion: The results provide clear evidence for deterioration of the structure of semantic knowledge for odors in AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic relations and Alzheimer's disease: Typicality and direction of testing.

Alzheimer's disease (AD) patients and elderly controls verified semantic attributes of common concepts. For each attribute tested (superordinate category, part, property, and function), typicality of the semantic relation was varied, as well as the order in which relations were tested (e.g., category-concept or concept-category). Like controls, AD patients showed decreased accuracy and increased response times as typicality decreased across the range of attributes tested and for both test orders. Overall, the findings indicate that the early stages of AD result in a systematic deficit in which the relations among semantic concepts remain orderly rather than in a disordering of the relations among concepts. The findings are discussed in relation to 2 major theoretical interpretations of semantic deficits in AD: degraded structure and disrupted processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metrical structure in planning the production of spoken words.

According to most models of speech production, the planning of spoken words involves the independent retrieval of segments and metrical frames followed by segment-to-frame association. In some models, the metrical frame includes a specification of the number and ordering of consonants and vowels, but in the word-form encoding by activation and verification (WEAVER) model (A. Roelofs, 1997), the frame specifies only the stress pattern across syllables. In 6 implicit priming experiments, on each trial, participants produced 1 word out of a small set as quickly as possible. In homogeneous sets, the response words shared word-initial segments, whereas in heterogeneous sets, they did not. Priming effects from shared segments depended on all response words having the same number of syllables and stress pattern, but not on their having the same number of consonants and vowels. No priming occurred when the response words had only the same metrical frame but shared no segments. Computer simulations demonstrated that WEAVER accounts for the findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic memory in Alzheimer's disease: Representativeness, ontologic category, and material.

Alzheimer's disease (AD) patients with semantic memory difficulty and AD patients with relatively preserved semantic memory named pictures and judged the category membership of words and pictures of natural kinds and manufactured artifacts that varied in their representativeness. Only semantically impaired patients were insensitive to representativeness in their category judgments. AD subgroup judgments did not differ for natural kinds compared to manufactured artifacts nor for words compared to pictures. AD subgroup differences could not be explained by dementia severity, memory, reading, and visuoperception. The similarity process for relating coordinate members of a taxonomic category contributes to the normal appreciation of word and picture meaning, and this process is compromised in AD patients with semantic difficulty. (PsycINFO Database Record (c) 2010 APA, all rights reserved)