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PubMed1996

Development of a brief measure of semantic priming.

Neuropsychologists use a variety of stimuli to investigate semantic memory functioning. Methodological concerns limit interpretation of performance differences between patients and nonpatient controls. The present study describes the development of a brief measure of semantic memory. Results indicate that this measure of semantic priming provides a brief, yet sensitive, measure of semantic memory. It may prove useful for researchers interested in examining semantic memory processes in cognitively impaired individuals.

Adult↗

PubMed1996

Automatic semantic facilitation in Alzheimer's disease.

To explore the nature of semantic deficit in Alzheimer's disease patients (AD patients) we compared two tasks that are known to be very different with respect to the type of attentional demand and conscious effort they require: lexical decision (automatic) in a semantic priming paradigm and semantic relatedness judgements (intentional). In order to minimise post-lexical facilitation we devised a semantic priming experiment that met an automatic condition as much as possible, and we selected patients without severe word recognition deficits. AD patients showed reduced accuracy in the semantic relatedness judgements as compared to controls. Some effect of priming was found, but this was weaker than in normals. AD patients also differed from controls on targets preceded by a nonlinguistic prime (neutral condition) where their reaction times were slower as compared to neutral condition.

Aged↗

PubMed1997

Semantic memory impairments following non-progressive brain injury: a study of four cases.

Four brain-injured subjects with semantic memory impairments are described. Two had sustained traumatic head injury and two had herpes simplex virus encephalitis. The study seeks to determine (a) whether subjects with non-progressive brain injury and impaired semantic memory perform similarly to patients with progressive disorders on a semantic memory battery and (b) whether the anatomical lesions of the present group of subjects are similar to those seen in patients with progressive disorders. Results suggests that scores on the semantic memory battery are broadly similar for patients with progressive and non-progressive disorders information from magnetic resonance imaging scans supports other findings that the crucial area involved in semantic memory lies in the left temporal neocortex.

Adolescent↗

PubMed2002

Attention to local form information can prevent access to semantic information.

Humphreys and Boucart (1997) have shown that when processing of local form is required for response, surrounding global information is automatically processed to a semantic level. The generality of this effect was investigated in two experiments in which the perceptual load of the relevant local form information was manipulated, as was uncertainty about perceptual load. Participants attended to a single line segment inside a picture of an animal or a vehicle and then decided which of two pictures in the target/distractor display that followed contained a line segment that matched the first in orientation. The perceptual load of the relevant local form information was either low (the matching line segment was one of the solitary line segments presented in the centre ofthe target and distractor pictures), or high (the matching line segment was part of one of the solitary letters presented in the centre of the target and distractor pictures). The semantic relations among the pictures were manipulated, and when perceptual load remained constant across trials, semantic relations affected performance in the low-load but not in the high-load condition. When perceptual load varied from trial to trial, there was no evidence of any semantic processing on either low- or high-load trials. The results suggest that in form-matching tasks, attentional priority can be given to local information, thus preventing access to semantic information derived from global shape. They further suggest that the distribution of attention is not dictated entirely by the actual perceptual demands of the relevant stimulus, indicating an important role for top-down processing.

Adult↗

PubMed2005

Refractory effects in picture naming as assessed in a semantic blocking paradigm.

In the cyclic semantic blocking paradigm participants repeatedly name sets of objects with semantically related names (homogeneous sets) or unrelated names (heterogeneous sets). The naming latencies are typically longer in related than in unrelated sets. In Experiment 1 we replicated this semantic blocking effect and demonstrated that the effect only arose after all objects of a set had been shown and named once. In Experiment 2, the objects of a set were presented simultaneously (instead of on successive trials). Evidence for semantic blocking was found in the naming latencies and in the gaze durations for the objects, which were longer in homogeneous than in heterogeneous sets. For the gaze-to-speech lag between the offset of gaze on an object and the onset of the articulation of its name, a repetition priming effect was obtained but no blocking effect. Experiment 3 showed that the blocking effect for speech onset latencies generalized to new, previously unnamed lexical items. We propose that the blocking effect is due to refractory behaviour in the semantic system.

Association Learning↗

PubMedDate not supplied

The representation of semantic categories in aging.

Age differences in the representation of semantic information may underlie the cognitive decline observed in aging. The objective of the present study was to determine to what extent elderly and young subjects agreed in the representations of semantic categories. Ninety elderly (77 women, 13 men) and 90 young (74 women, 16 men) participants wrote down the first four associations evoked by each of 30 semantic category names. Results showed differences between the two groups in items selected as most common responses (MCRs); frequency of occurrence of the MCRs differed between the two groups in 21 semantic categories. Results suggest that young and elderly subjects hold different representations of semantic categories and also highlight the importance of using age-appropriate norms in the evaluation of cognitive functions in aging.

Aged↗

PubMedDate not supplied

Adult age differences in long-term semantic priming.

Young and older adults were first asked to decide if a list of individually presented words were "living" (e.g., "tree") or "nonliving" (e.g., "store"). This was termed the "orienting task." Next, subjects performed a pronunciation task. Semantic priming for young and older adults was indexed by determining if semantic congruence between words in the orienting task and words in the pronunciation task improved performance on the pronunciation task relative to pronounced words from semantic categories not primed in the orienting task. The present data, from two different experiments, revealed that subjects pronounced high-dominance exemplars of the "living" words primed in the orienting task faster than words not primed in the orienting task. These data indicated that semantic priming for relatively long prime-target stimulus onset asynchronies can occur, and that such priming is at least as robust for older adults as for young adults. The results are discussed in terms of four current models of semantic priming.

Adolescent↗

PubMed2006

A study of semantic treatment of three Chinese anomic patients.

A treatment combining semantic feature analysis and semantic priming was carried out on three Cantonese-speaking brain-injured individuals with word-finding difficulties. Two of the participants with mild to moderate semantic impairment demonstrated significant progress on naming performance. Treatment effects also generalised to semantically related and unrelated untrained items. However, only one of these two participants was able to maintain the treatment gain for at least one month after the therapy was completed. The third patient with severe semantic deficits did not benefit from the intervention. The different outcomes of these participants to the same intervention were explained in terms of the nature of the treatment approach, the patients' underlying language deficits, and their level of cognitive abilities.

Adult↗

PubMed2002

Episodic and semantic remote autobiographical memory in ageing.

Many laboratory studies have demonstrated an age effect on episodic memory which is in contrast with the preservation of semantic memory. The aim of this study was the assessment of age effects on autobiographical memory according to the length of the retention interval, taking into account the episodic and semantic components. A total of 52 subjects, aged between 40 and 79, were divided into four age groups. They were tested with a sophisticated autobiographical questionnaire consisting of two tasks, one involving the recall of semantic information and another the recall of episodic events. Results revealed that episodic recall deteriorated more with age and retention interval than semantic recall. These data, gathered using an ecological test, confirm age differences demonstrated by laboratory tests on the episodic-semantic distinction. Furthermore, the profile of results obtained for the recall of specific detailed events, and analysed according to age of encoding, confirms the distribution of episodic memories across the lifespan, as modelled by Rubin, Wetzler, and Nebes (1986) with the cue-word technique.

Adult↗

PubMed2006

The understanding of quantifiers in semantic dementia: a single-case study.

This study investigates the processing of quantifiers in a patient (AM) with semantic dementia. Quantifiers are verbal expressions such as "many" or "a few", which refer semantically to quantity concepts although lexically they are like non-quantity words. Patient AM presented with preserved understanding of quantifier words and impaired understanding of non-quantifier words of the same frequency. In parallel to this, he showed preserved numerical knowledge and impaired comprehension of the meaning of words, objects, and of linguistic concepts. These results suggest that the neural organization of quantifiers is within the numerical domain as they pattern with numerical concepts rather than linguistic concepts. These data reinforce the evidence that numerical knowledge is functionally distinct from non-numerical knowledge in the semantic system and indicate that the semantic referent rather than the stimulus format is more relevant for semantic processing.

Aged↗

PubMed2006

Semantic verbal fluency in Alzheimer's disease: approaches beyond the traditional scoring system.

This study aimed to expand extant Alzheimer's disease (AD) research on cluster size and switching strategies in semantic verbal fluency (SVF). First, it addressed a significant shortcoming in research, that is, the use of a single semantic category (i.e., Animal). Second, it examined subjects of lower education levels, as research to date has primarily focussed on tertiary education. Subjects were 26 mild to moderate AD patients and 26 healthy elderly, 65 years old and over, with less than 12 years of schooling. The study examined the cluster size and switching variables, together with the number of subcategories, in two semantic categories (i.e., Animal and Supermarket). Furthermore, it investigated the error patterns (i.e., repetitions and categorical errors) across three semantic categories (i.e., Animal, Supermarket and Furniture). The findings provide preliminary support for category-specific effects on qualitative aspects of SVF highlighting the need to incorporate multiple semantic categories to research and clinical practice.

Aged↗

PubMedDate not supplied

Covariates of production and perseveration on tests of phonemic, semantic and alternating fluency in normal aging.

Standard measures of phonemic and semantic fluency, as well as fluency measures that impose additional demands upon set-switching were administered to younger and older adults. No age effect was found for total output on semantic fluency, while older participants generated significantly more responses relative to their younger counterparts on the phonemic measure. However, older adults made significantly more perseverative errors on both these measures. For tests of alternating fluency, only where participants were required to switch between two semantic dimensions, was an age deficit observed. Although the correlation between phonemic repetitions and age remained significant when performance on the Digit Symbol Test or a measure of fluid intelligence was partialled out, age effects for semantic repetitions and semantic alternating fluency were substantially reduced. The age benefit for number of correct responses upon phonemic fluency was significantly attenuated when a measure of crystallized intelligence was entered as a control variable. The theoretical and practical implications of these results are discussed.

Adolescent↗

PubMed1999

Semantic similarity and immediate serial recall: is there a detrimental effect on order information?

Four experiments investigated the disruptive effect of semantic similarity on short-term ordered recall. Experiments 1 and 2 contrasted immediate serial recall performance for lists of semantically similar items, drawn from the same semantic category, with performance for lists that contained items from different categories. Experiments 1 and 2 showed the usual similarity advantage for item information recall, but, contrary to expectations, there was no similarity disadvantage for the recall of order information even when the level of item recall was controlled. Experiments 3 and 4 replicate and extend these findings by using an order reconstruction task or a limited word pool strategy, both of which yield alternate measures of order retention. These findings clearly contradict the wide spread belief stating that semantic similarity hinders the short-term recall of order information. Results are discussed in the light of a retrieval-based account where the effects of semantic similarity reflect the processes called upon at recall: It is suggested that long-term knowledge is accessed to support the interpretation of degraded phonological traces.

Adult↗

PubMed2004

Changes in semantic uses of first person pronouns as possible linguistic markers of recovery in psychotherapy.

OBJECTIVE: To examine changes in linguistic markers in the course of psychotherapy, drawing on Frege's logic of relations to define semantic variables distinct from syntactic variables. METHOD: From a sample of 73 patients, 10 patients with the best and 10 patients with the worst outcomes were selected. Forty transcribed sessions of each outcome group were compared statistically for change between commencement and termination of psychotherapy in: (i) the syntactic usage of first person pronouns ('I', 'me', 'we', 'us', 'implied I', 'implied me'); (ii) semantic usage of first person pronouns (expressing alpha, omega, or unclear positions); and (iii) non-pronoun linguistic variables (passive voice, negative, copula, auxiliary verbs expressing a sense of obligation). RESULTS: There were no significant differences between the best and worst outcome groups in the change of either syntactic usage, or of the non-pronoun linguistic variables. However, the outcome groups differed significantly in the change of their semantic usage (alpha: p = 0.002; omega: p = 0.028): The best outcome group showed an increase of alpha positions and a decrease of omega positions, whereas the worst outcome group showed the inverse (i.e. decrease of alpha and increase of omega positions). CONCLUSIONS: Results suggest only semantic, that is meaning-driven, usage of first person pronouns marks recovery in the course of psychotherapy. If replicated, this finding could be used to monitor treatment responses. Replication in other kinds of treatment could mean these semantic changes are markers of recovery more generally than in psychotherapy.

Humans↗

PubMed2004

Semantic search among heterogeneous biological databases based on gene ontology.

Semantic search is a key issue in integration of heterogeneous biological databases. In this paper, we present a methodology for implementing semantic search in BioDW, an integrated biological data warehouse. Two tables are presented: the DB2GO table to correlate Gene Ontology (GO) annotated entries from BioDW data sources with GO, and the semantic similarity table to record similarity scores derived from any pair of GO terms. Based on the two tables, multifarious ways for semantic search are provided and the corresponding entries in heterogeneous biological databases in semantic terms can be expediently searched.

Database Management Systems↗

PubMed1981

Age-related facilitation in recall following semantic processing.

The present experiment was an attempt to reduce or eliminate the age-related deficit in recall following a semantic processing task. It was hypothesized that variables that might affect depth or elaborateness of semantic processing would consequently affect the size and direction of recall differences between younger and older adults. Specifically, we tested for the effects of differential word familiarity and one vs two semantic tasks on recall in young and older adults following semantic processing. The results demonstrated that word familiarity and number of processing tasks both had a strong effect on recall. Older adults benefited as much from additional semantic processing as younger adults. Additionally, older adults actually showed higher recall than younger adults when subjects processed words more familiar to older adults. These results demonstrate that, given appropriate conditions, older adults may actually show higher performance in a memory task than younger adults.

Adolescent↗

PubMed1986

Age-related slowing in semantic information processing speed: an individual differences analysis.

This study investigated age differences in the speed of processing semantic information. Thirty young adults and 25 older adults completed five reaction time (RT) tasks: simple RT, two-choice RT to nonverbal stimuli, and three tasks measuring speed of making semantic judgments. The data were used to examine individual differences in RT factors, estimated by means of confirmatory factor analysis. All three semantic RT tasks loaded on a single semantic RT factor, with equivalent factor loadings for young and older participants, indicating that the three tasks were measuring a common factor of semantic memory access speed (SMA). The two groups differed significantly in the covariances among the RT factors; most important, the SMA factor had a higher correlation with a two-choice RT factor in the older group. This finding is taken as support of individual differences in age-related slowing on these two RT factors.

Adult↗

PubMed1989

Age and semantic inhibition in word retrieval.

An experiment to identify the source of age-related inhibition by semantically related primes in a word-retrieval paradigm is reported. Stimuli were definitions of target words, and responses were names of the target words that were defined. It has been shown previously that in this paradigm older adults are differentially inhibited by semantically related primes (Bowles & Poon, 1985a). The present experiment was designed to test the hypothesis that the additional inhibition by semantically related primes resulted from a decision strategy adopted by older adults when the primes themselves were sometimes correct target words. When the correct prime condition was eliminated in the present experiment, response times were statistically the same for semantically related and unrelated conditions for both older and younger adults. This suggests that the inhibition was due to additional decision processing performed by older adults rather than to longer retrieval processing in the presence of semantically related primes.

Adult↗