SEARCH · PubMed Health

Results for “Semantics”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,153 records · Page 64Linked to original sources

PubMed2001

Names and words without meaning: incidental postmorbid semantic learning in a person with extensive bilateral medial temporal damage.

The authors describe a densely amnesic man who has acquired explicit semantic knowledge of famous names and vocabulary words that entered popular culture after the onset of his amnesia. This new semantic knowledge was temporally graded and existed over and above the implicit memory he demonstrated in reading speed and accuracy, familiarity ratings, and his ability to make correct guesses on unfamiliar items. However, his postmorbid knowledge was limited to verbal labels denoting famous people and words; he possessed virtually no explicit knowledge of the meaning of these words or the identities of these individuals, although there was some evidence that some of this information had been acquired at an implicit level. Findings are discussed in the context of a neural network model (J. L. McClelland, B. L. McNaughton, & R. C. O'Reilly, 1995) of semantic acquisition.

Amnesia↗

PubMed2001

The semantic--procedural interface model of the self: the role of self-knowledge for context-dependent versus context-independent modes of thinking.

How do independent and interdependent self-construals affect cognition? The authors proposed the semantic-procedural interface model, which distinguishes 2 such mechanisms. In addition to semantic differences, different procedural modes of thinking are associated with independent and interdependent self-construals. Independent self-definitions coincide with the tendency to process stimuli unaffected by the context in which they appear. Interdependent self-construals facilitate context-bounded thinking (i.e., processing stimuli by paying attention to their relation to the given context). With semantic-free dependent variables, 4 experiments showed independence-primed participants to exhibit higher degrees of context independence than did interdependence-primed participants. The results are discussed with reference to their potential explanations for cross-cultural differences.

Adult↗

PubMed2000

Individual and developmental differences in semantic priming: empirical and computational support for a single-mechanism account of lexical processing.

Existing accounts of single-word semantic priming phenomena incorporate multiple mechanisms, such as spreading activation, expectancy-based processes, and postlexical semantic matching. The authors provide empirical and computational support for a single-mechanism distributed network account. Previous studies have found greater semantic priming for low- than for high-frequency target words as well as inhibition following unrelated primes only at long stimulus-onset asynchronies (SOAs). A series of experiments examined the modulation of these effects by individual differences in age or perceptual ability. Third-grade, 6th-grade, and college students performed a lexical-decision task on high- and low-frequency target words preceded by related, unrelated, and nonword primes. Greater priming for low-frequency targets was exhibited only by participants with high perceptual ability. Moreover, unlike the college students, the children showed no inhibition even at the long SOA. The authors provide an account of these results in terms of the properties of distributed network models and support this account with an explicit computational simulation.

Adult↗

PubMed2006

Semantic activation in action planning.

Four experiments investigated activation of semantic information in action preparation. Participants either prepared to grasp and use an object (e.g., to drink from a cup) or to lift a finger in association with the object's position following a go/no-go lexical-decision task. Word stimuli were consistent to the action goals of the object use (Experiment 1) or to the finger lifting (Experiment 2). Movement onset times yielded a double dissociation of consistency effects between action preparation and word processing. This effect was also present for semantic categorizations (Experiment 3), but disappeared when introducing a letter identification task (Experiment 4). In sum, our findings indicate that action semantics are activated selectively in accordance with the specific action intention of an actor.

Analysis of Variance↗

PubMed2005

Long-lasting semantic context effects in the spoken production of object names.

A number of recent studies have found that objects are named more slowly in the context of same-category items than in the context of items from various semantic categories. Several experiments reported here indicated that this semantic effect is relatively persistent because it was essentially unaffected by the presence of interspersed filler items. The authors suggest that the effect is specific to the retrieval of lexical-semantic codes and characterize mechanisms that could support the effect at this processing level, such as incremental learning in the links between conceptual and lexical codes and the temporary increase of lexical resting levels. The results underscore the necessity of incorporating mechanisms of long-term adaptation into current models of spoken production.

Humans↗

PubMed2003

What are the causes of reduced fit in scaling and clustering studies of semantic proximity data, and how else to measure them: a comment on Storms et al. (2003).

G. Storms, T. Dirikx, J. Saerens, S. Verstraeten, and P. P. De Deyn (2003) noted that the goodness-of-fit indices for scaling and clustering solutions of proximity data from populations with hypothesized semantic deficits tend to be reduced in comparison with control participants, and that this precludes an unambiguous interpretation of such data. However, this effect is not necessarily as inconsistent with the proposal of semantic degradation in these groups, or as consistent with explanations in terms of access or attentional problems, as is suggested by G. Storms et al. Also, although performance on word fluency tasks is certainly constrained by the ability to access stored information, there are ways in which this confounding influence may be controlled for in the study of semantic deficits.

Cluster Analysis↗

PubMed2003

Taking the thumbs off the multidimensional scales in the debate on semantic memory and Alzheimer's disease: a comment on Storms et al. (2003).

G. Storms, T. Dirikx, J. Saerens, S. Verstraeten, and P. P. De Deyn (2003) bring into focus at least 3 important issues. First, the performance of even simple tasks may be affected by several basic cognitive processes. Second, the statistical variance that these processes contribute to task performance may be different for a group of participants with neuropsychological deficits than for normal control particpants. Third, claims regarding the nature of semantic memory in Alzheimer's disease (AD) reflect indeterminacy about the nature and assessment of semantic memory itself. Critically, their analysis suggests that the T. Shallice and E. K. Warrington (1979) criteria widely used to operationalize the semantic memory deficit in AD be carefully scrutinized and reevaluated.

Alzheimer Disease↗

PubMed2003

New directions in the study of semantic deficits: a comment on Storms et al. (2003).

G. Storms, T. Dirikx, J. Saerens, S. Verstaeten, and P. P. De Deyn (2003) have provided an important critique of the use of multidimensional scaling (MDS) to evaluate semantic knowledge in Alzheimer's disease. If MDS is to be used with semantic proximity data (in spite of well-documented reasons for not doing so), at minimum, the issues raised in G. Storms et al. should be considered. A few criticisms of the target article are presented. Then, the manner in which key points from the article, along with a consideration of such factors affecting proximity elicitation as semantic domains, tasks, and the experimental context, could be applied to correct certain shortcomings in the literature are discussed.

Alzheimer Disease↗

PubMed2005

Working memory capacity, indirect semantic priming, and stroop interference: pattern of interindividual prefrontal performance differences in healthy volunteers.

Using neuropsychological models of prefrontal function, the authors investigated the pattern of interindividual prefrontal performance differences in healthy volunteers. Using a correlation and an extreme group approach, they compared verbal and visuospatial working memory capacity with performance on the Stroop interference task as a measure of executive control and on the direct and indirect semantic priming tasks as a measure of semantic access. Subjects with low visuospatial working memory capacity exhibited increased Stroop interference Subjects with low verbal memory capacity showed increased priming and Stroop interference only. The study shows that prefrontal functioning varies interindividually, forming patterns of performance differences. These findings suggest that working memory, executive control, and semantic retrieval are functionally related to some extent.

Adult↗

PubMed1993

Eye movement control during visual object processing: effects of initial fixation position and semantic constraint.

Eye movement patterns were recorded while subjects viewed arrays of line drawings of objects. The initial landing position of the eyes on an object was found to be normally distributed around the center of the object, with the modal landing position at the center. Landing variability was greater in the direction of the eye movement vector than in the direction perpendicular to the movement, and there was more of a tendency to undershoot the center of the object than to overshoot it. Landing position was found to influence other aspects of eye movement behaviour. The duration of the first fixation on an object decreased and the probability of refixating an object increased as the deviation of the initial landing position from the center of the object increased. The effect of a cognitive factor, semantic constraint, was also examined. Landing position and semantic constraint were found to interact such that semantic constraint had a greater effect the further the eyes landed from the center of the object. The results are discussed in terms of their implications for the use of eye movement behaviour as an indicator of perceptual and cognitive processing.

Adult↗

PubMed2002

When are morphemic and semantic priming observed in visual word recognition?

J. Stolz and D. Besner (1998) reported a dissociation between morphemic and semantic priming in the context of lexical decision. Morphemic priming was observed following letter search on the prime display, but semantic priming was not. Participants in the present experiment identified the colour of a single letter in the prime display before making a lexical decision to the target. Both morphemic and semantic priming were observed. These results are discussed in relation to the observation that identifying the colour of a single letter of a word in the Stroop task is associated with a reduction in the size of the Stroop effect as compared to when all letters are coloured.

Analysis of Variance↗

PubMed2004

Semantic features in fast-mapping: performance of preschoolers with specific language impairment versus preschoolers with normal language.

This study examined the receptive language skills of young children (4-6 years old) with specific language impairment (SLI). Specifically, the authors looked at their ability to fast-map semantic features of objects and actions and compared it to the performance of age-matched peers with normally developing language (NL). Children completed a computer task during which they were exposed to novel objects and actions with novel names. The children then were asked questions about the semantic features of these novel objects and actions. Overall, the questions about actions were more difficult for children than objects. The children with SLI were able to recognize fewer semantic features than were their peers with NL. They also performed poorly relative to their peers on a lexical label recognition task. These results lend support to the idea that children with SLI have broader difficulties with receptive vocabulary than simply a reduced ability to acquire labels.

Analysis of Variance↗

PubMed2006

Lexical-semantic organization in bilingual children: evidence from a repeated word association task.

PURPOSE: This study examined lexical-semantic organization of bilingual children in their 2 languages and in relation to monolingual age-mates. METHOD: Twelve Mandarin-English bilingual and 12 English monolingual children generated 3 associations to each of 36 words. Responses were coded as paradigmatic (dog-cat) or syntagmatic (dog-bark). RESULTS: Within the bilingual group, word association performance was comparable and correlated between 1st and 2nd languages. Bilingual and monolingual children demonstrated similar patterns of responses, but subtle group differences were also revealed. When between-group comparisons were made on English measures, there was a bilingual advantage in paradigmatic responding during the 1st elicitation and for verbs. CONCLUSION: Results support previous studies in finding parallel development in bilinguals' 1st- and 2nd-language lexical-semantic skills and provide preliminary evidence that bilingualism may enhance paradigmatic organization of the semantic lexicon.

Analysis of Variance↗

PubMed2006

Factors that influence lexical and semantic fast mapping of young children with specific language impairment.

PURPOSE: This purpose of this study was to investigate the lexical and semantic fast mapping ability of young children with specific language impairment (SLI) and normal language (NL), with a specific emphasis on the influence of phonological factors. METHOD: The study included 46 children (mean age 58 months), half with SLI and half with NL. Children were asked to fast map visual information only, visual-plus-nonlinguistic-auditory information, and visual-plus-linguistic-auditory information. A mixed design was used to compare children across and within groups. RESULTS: Children with SLI performed worse than children with NL overall. The SLI group showed specific deficits in semantic fast mapping when they saw visual information only. This condition may have disrupted encoding because it varied from the expected auditory and visual pattern. The children with SLI also performed poorly when they were asked to map phonotactically infrequent linguistic information and when the difficulty of the task increased. A nonword repetition task was correlated with both semantic and lexical fast mapping. CONCLUSIONS: The findings are discussed in the light of their support for a limited capacity model of processing, as well as the impact of phonology on word learning.

Case-Control Studies↗

PubMed1977

Aphasia: a divergent semantic interpretation.

The present paper reinterprets aphasia relative to the divergent and convergent components of Guilford's model of behavior. It suggests that some aphasiologists have defined aphasia as a convergent semantic disorder. They have determined the presence or absence of an aphasic impairment on the basis of each individual's ability to recognize and reproduce previously learned material and to converge upon one correct answer. The present analysis also shows that there are a number of theoretical models of aphasia which indicate that aphasia involves more than a convergent semantic impairment. Aphasia, interpreted according to Guilford's model, appears to have a divergent component. Aphasia involves a decrease in an individual's ablilty to provide ideas in situations where a proliferation of ideas on some topic is required, or to extend the boundaries of what he already knows. The individual who is impaired in his ability to produce a number of relevant ideas and a variety of different kinds or categories of responses has a divergent semantic impairment.

Aphasia↗

PubMed1981

Comprehension and production of basic semantic concepts by older hearing-impaired children.

Comprehension of semantic concepts considered basic to academic performance in the early grades was evaluated with the Boehm Test of Basic Concepts (BTBC) for 15 orally trained, severely and profoundly hearing-imparied children, ages 13--14 years. The children also were required to construct written sentences using these same concepts. Teachers of the hearing-impaired children completed a questionnaire of their expectation levels of the vocabulary competence, comprehension, and production for each child on the 50 items of the BTBC. Classroom texts used by the children were examined for the presence of these specific concepts. The measure of comprehension showed that four-fifths of the children scored lower than the 10th percentile for second-grade hearing children, and two-thirds scored at or below the 1st percentile. Evaluating production, 68% of the sentences produced by the children contained semantic, syntactic, or semantic-syntactic errors. The individual's level of vocabulary comprehension was higher than each child's level of production. Classroom teachers were able to predict accurately each child's comprehension and production scores. Finally, the survey of the classroom textbooks used by the children revealed that approximately 80% of the BTBC test items appeared within the texts. Implications are discussed.

Achievement↗

PubMed1982

The effects of temporal and semantic conditions on the occurrence of the error response of perseveration in adult aphasics.

This study sought to determine whether the incidence of perseveration in the responses of adult aphasics could be affected by altering stimulus factors such as semantic difficulty and the rate of presentation of stimuli. Thirty-one aphasic men supplied 1-word responses within three randomly arranged language tasks: sentence completion, picture naming, and word reading. Within each task subjects received stimuli from two 20-word lists of words contrasted for their frequency of occurrence in the language. Each list was presented once with 1-sec intervals between subjects' responses and subsequent stimuli, and once with 10-sec intervals. Results indicated that when semantic difficulty as measured by the frequency of occurrence of the single-word responses was reduced, the mean number of perseverations decreased significantly. When time intervals were increased from 1 to 10 seconds, perseverations decreased significantly. Sentence completion and picture naming elicited significantly more perseverations than word reading. Perseveration and other verbal errors were similarly affected by the variable of semantic difficulty, but only perseverative errors were significantly reduced when time intervals were increased. Word length, presentation order of tasks and conditions, and time postonset of aphasia appeared to have little relationship to perseveration.

Adult↗

PubMed1986

Acquisition of semantic role by language-disordered children: differences between production and comprehension.

Six 3-year-old language-disordered children were taught the relationship between semantic role and word order through either production or comprehension training. All 6 subjects successfully learned the relationship through production training as indicated by their responses to a production probe and by their use of word order to express semantic role distinctions in their conversational speech. These subjects never used word order cues to decode semantically reversible sentences on comprehension tests even after they were using word order appropriately in their conversational speech. Also, none of the subjects were able to learn word order through comprehension training. The results were interpreted to mean the subjects could learn a word-order rule by teaching them to say sentences that contrast word order and meaning but that they could not learn by being taught to respond to sentences. The problem with this latter procedure may be that it requires a mental operation that is beyond the level of cognitive development of children under the age of 4.

Child, Preschool↗