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PubMed2003

Computerizing reading training: evaluation of a latent semantic analysis space for science text.

The effectiveness of a domain-specific latent semantic analysis (LSA) in assessing reading strategies was examined. Students were given self-explanation reading training (SERT) and asked to think aloud after each sentence in a science text. Novice and expert human raters and two LSA spaces (general reading, science) rated the similarity of each think-aloud protocol to benchmarks representing three different reading strategies (minimal, local, and global). The science LSA space correlated highly with human judgments, and more highly than did the general reading space. Also, cosines from the science LSA spaces can distinguish between different levels of semantic similarity, but may have trouble in distinguishing local processing protocols. Thus, a domain-specific LSA space is advantageous regardless of the size of the space. The results are discussed in the context of applying the science LSA to a computer-based version of SERT that gives online feedback based on LSA cosines.

Artificial Intelligence↗

PubMed1989

A semantic memory sentence verification model based on relative judgment theory.

A subjective referent model of sentence verification in semantic memory tasks based on the relative judgment theory of Link and Heath (1975), together with the derivation of a discriminability index, are presented in this paper. An attractive feature of the model is its consideration of both error rates and response times (RTs) in the calculation of the discriminability index. The model is also able to account for the frequent finding in semantic memory tasks that error RTs are longer than correct RTs. A partial replication of Experiment 2 of McCloskey and Glucksberg's (1979) sentence verification context effect studies, in which we employed 44 subjects and 28 categories, and controlled for item familiarity, revealed that error RTs were consistently longer than correct RTs--a finding inconsistent with the McCloskey and Glucksberg property comparison model, but in accord with the subjective referent model. An important fortuitous result was the detection of a context effect by the discriminability measure, an effect not detected by the RT data alone. The discriminability measures yielded a near perfect correlation with estimates of the mean step size of the random walk obtained by application of the parameter estimation program FITTRW (Heath, 1983).

Adult↗

PubMed2001

Searching for two things at once: evidence of exclusivity in semantic and autobiographical memory retrieval.

We examined whether retrieval from semantic memory (Experiment 1) and autobiographical memory (Experiment 2) is exclusive, or whether people can search for two things at once. In Experiment 1, participants retrieved items as quickly as possible over 4 ruin from single categories (e.g., foods, countries) and from disjunctive categories (e.g., foods or countries). In Experiment 2, participants retrieved autobiographical episodes associated with single cue words (e.g., flower, ticket) or with disjunctive cue words (e.g., flower or ticket). In both experiments, retrieval of items from the disjunctive category did not exceed predictions based on optimal sequencing of retrieval from the corresponding two single categories. That is, exclusivity was observed to occur in retrieval from among multiple nonoverlapping categories in both semantic and autobiographical memory.

Adolescent↗

PubMed1993

The effect of semantic priming on the detection of letters within words.

Smith (1979) reported an experiment in which subjects were to detect whether or not a displayed word contained a particular target letter. Her data indicated that if the word bearing the target letter was preceded by a semantically related item, the detection of the target letter was faster than it was if the preceding item was unrelated. Those results provided strong support for holistic models of word recognition, in which it is assumed that letter detection must be mediated by prior word recognition. That is, any facilitating effect of the prime on lexical access should be passed on to subsequent letter detection. The present experimental paradigm, which was very similar to (albeit different from) that of Smith, served to explore the generality of her effect, but the results did not confirm her findings. Although a lexical-decision task used in Experiments 2, 5, and 7 provided clear evidence that the priming items employed in these experiments did facilitate lexical processing, a letter-detection task used in Experiments 1, 3, 4, 6, and 8 failed to reveal any facilitating effect of semantic priming on letter detection. The conclusion is that the generality of Smith's effect is far too limited to offer support for holistic models of word recognition.

Adult↗

PubMed1994

Capacity demands of automatic processes in semantic priming.

In three experiments, we examined the effects of prime-target stimulus onset asynchrony (SOA) and the proportion of related primes and targets (relatedness proportion, or RP) on semantic priming when the prime was either named or was searched for a specific letter. In Experiment 1, with an RP of .50, priming occurred at SOAs of 240 and 840 msec when the prime was named, but no priming was found at either SOA when the prime was searched for a letter. In Experiment 2 the RP was either .20 or .80, and the SOA was set at 1,700 msec; priming again was found in both conditions when the prime was named, but only in the RP .80 condition when a letter search task was performed on the prime. In Experiment 3, both the proportion of related trials and SOA were varied; as in the previous experiments, no priming effects were found with the letter search task for either SOA in the RP .20 condition, but the priming effect was reinstated in the RP .80 condition. These results are discussed with respect to how limited capacity resources are allocated and how they influence semantic priming effects.

Discrimination, Psychological↗

PubMed1998

When do nonwords activate semantics? Implications for models of visual word recognition.

Three lexical decision experiments examined the conditions in which nonwords activate semantics. Lexical decisions to targets (e.g., CAT) were faster when preceded by semantically related nonword primes (e.g., DEG derived from DOG) when the prime was brief and masked; this nonword priming effect was eliminated when the prime was presented for a longer duration. These results are discussed in the context of both parallel distributed processing models and the idea that the occurrence of nonword priming depends upon subjects being unable to verify the identity of the prime.

Analysis of Variance↗

PubMed1998

Orthography and phonology in reading Japanese kanji words: evidence from the semantic decision task with homophones.

Correspondences between spelling and sound for Japanese kanji are complex and deep. The meaning of kanji words has generally been assumed to be accessed directly from orthography without phonological mediation. Experiment 1, however, replicated the findings of Van Orden (1987) that subjects made more false-positive errors on homophone foils than they did on nonhomophone controls in a semantic decision task, although they did so only when the foils were orthographically similar to the correct exemplars, which indicates both orthographic and phonological activations of meaning. Experiment 2 showed the same results when subjects were not required to pronounce the target words after semantic decisions, which indicates automatic phonological activation of kanji words. In Experiment 3, under pattern-masking conditions, this homophony effect was reduced but remained on errors, and the orthographic-similarity effect remained strong on both homophone and nonhomophone foils. These results suggest that both orthography and phonology play an important role in the comprehension of kanji words.

Adult↗

PubMed1999

Orthographic neighborhood effects in perceptual identification and semantic categorization tasks: a test of the multiple read-out model.

How should a word's orthographic neighborhood affect perceptual identification and semantic categorization, both of which require a word to be uniquely identified? According to the multiple read-out model (Grainger & Jacobs, 1996), inhibitory neighborhood frequency effects should be observed in these types of tasks, and facilitatory neighborhood size effects should not be. In Experiments 1 and 2 (perceptual identification), these effects were examined as a function of stimulus visibility (i.e., high vs. low visibility) to provide as full a test as possible of the model's predictions. In the high-visibility conditions, words with large neighborhoods were reported less accurately than words with small neighborhoods, but there was no effect of neighborhood frequency (i.e., whether the word had a higher frequency neighbor). In the low-visibility conditions, low-frequency words with large neighborhoods and low-frequency words with higher frequency neighbors showed superior identification performance. In the semantic categorization task (Experiment 3), words with large neighborhoods were responded to more rapidly than words with small neighborhoods, but there was no effect of neighborhood frequency. These results are inconsistent with two of the basic premises of the multiple read-out model--namely, that facilitatory neighborhood size effects are due to a variable response criterion (the sigma criterion), rather than to lexical selection processes, and that the lexical selection processes themselves produce an inhibitory neighborhood frequency effect (via the M criterion). Instead, the present results, in conjunction with previous findings, suggest that large neighborhoods (and perhaps higher frequency neighbors) do aid lexical selection.

Adult↗

PubMed2002

The effect of asymmetrical association on positive and negative semantic priming.

One's actively ignoring a stimulus can impair subsequent responding to that stimulus. This negative priming effect has been argued to generalize to semantically related items as well, but the evidence for this is still somewhat weak. This article presents a new experiment in which participants made lexical decisions to asymmetrically associated prime-target pairs presented in either the forward (e.g., stork-baby) or backward (e.g., baby-stork) direction. The critical new finding was that both attended positive and ignored negative semantic priming occurred only for prime-target pairs presented in the forward direction. The results support either (1) a spreading inhibition model in which items associated with an ignored distractor are inhibited during prime selection or (2) a version of episodic retrieval theory in which the prime distractor and items associated with it are tagged as "to-be-ignored" during prime selection.

Affect↗

PubMed1991

Semantic processing of unattended text during selective reading: how the eyes see it.

Subjects were instructed to read and comprehend a target (attended) passage while eye movements were recorded. A second (unattended) passage was also present, with attended and unattended passages occupying alternating lines of text. Subsequent multiple-choice questions showed acquisition of semantic information from attended and unattended text. However, a detailed examination of eye-fixation records showed that readers occasionally fixated unattended text, indicating the presence of shifts of visual attention to unattended text. When fixations of unattended text were excluded, there was no longer any indication that readers obtained useful semantic information from unattended text.

Attention↗

PubMed1985

[Semantic priming effect on the perception of a Kanji].

A priming experiment was conducted to investigate how semantic context affects the perception of a briefly exposed Kanji target. On each trial, a Kanji or a plus (neutral) was presented as the prime stimulus for 1 s. When the prime was a Kanji, subjects were required to imagine any compound word, the first letter of which was to be that prime. After a blank of 500 ms, a target Kanji was briefly exposed followed by a patterned mask and two response alternatives, one of which the subject was asked to choose. The duration of the target was so adjusted that each subject could respond correctly at approximately 75% level. The % choice response was higher when the prime and the target made up a compound word (related condition) and also matched to the imagined word (facilitation) than when not (neutral condition). When the prime and the target were unrelated, the performance was the worst (inhibition). In the related condition, however, responses were more accurate even when the prime-target pair did not match to the imagined compound word than in the unrelated condition. These results suggest that semantic priming effect occurs automatically regardless of whether the subject may expect the target or not.

Adult↗

PubMed1999

Semantic based concept differential retrieval & equivalence detection in clinical terms version 3 (Read Codes).

Modern clinical terminologies are required to provide a large corpus of concepts to cover the complexity of medicine. It is well recognised that sufficient scalability is likely to be achieved only with those schemes that can build post-coordinated constructs compositionally. Clinical Terms Version 3 (Read Codes) uses a system of templates to both express the semantic definition (atoms) of concepts and to allow qualification of core concepts with additional detail. This common mechanism for expressing both intrinsic semantic information and additional information allows both pre- and post-coordinated concepts to be retrieved from different perspectives and to detect equivalence between alternative representations of the same concept. The practical application and experience of such an approach is described in relation to a live clinical database (Diabeta). The merits of such an approach are outlined and its relationship to other documented mechanisms outlined.

Classification↗

PubMedDate not supplied

Phonological and semantic information in word and nonword reading in a deep dyslexic patient.

Deep dyslexia is diagnosed when brain-injured, previously literate adults make reading errors that include hallmark semantic paralexias (e.g., reading HEART as BLOOD) and are also impaired at reading nonwords (e.g., FRIP). The diversity of these symptoms have led most researchers to conclude that there are multiple sources of impairment in this syndrome and that one of the most critical is a failure to process phonological information at a sublexical level. The patient (SD) reported in this study fits the deep dyslexia profile to the extent that she makes several semantically related reading errors. She also shows the classic frequency and image ability effects of the syndrome. However, as we report, she does read some nonwords correctly and she shows a strong advantage for naming when phonemic cues are presented. We discuss the performance of SD, on these preliminary tasks, in terms of a phonological selection impairment.

Dyslexia↗

PubMedDate not supplied

[Validation of a model for the prediction of verbal semantic fluency].

INTRODUCTION: The diagnosis of dementia requires documentation of cognitive loss with respect to the patient's previous level. It would therefore be very useful to have models available which would predict the result expected in the tests normally used in the diagnosis of dementia. OBJECTIVE: To validate a model for prediction of the results of a test of semantic verbal fluency in persons with no dementia. PATIENTS AND METHODS: A model for the prediction of semantic verbal fluency deduced from a sample of 138 persons was applied to two other independent samples: the first of 86 persons from the same environment as the original sample and a second multicentric sample of 92 persons. The validity of the model was evaluated by residual analysis. RESULTS: No sex differences were seen between the samples, but there were differences regarding the other variables, including the observed and predicted verbal fluency. The residuals of the samples did not differ from each other nor vary from zero, but were normally distributed. CONCLUSION: The model proposed based on sociodemographic and clinical variables is valid and satisfactorily predicts the verbal fluency to be expected in each case.

Aged↗

PubMed2000

Using UMLS semantics for classification purposes.

The Unified Medical Language System (UMLS) contains semantic information about terms from various sources; each concept can be understood and located by its relationships to other concepts. We describe a method in which the semantic relationships between UMLS concepts are exploited for the purpose of classification. This method combines three existing components: 1) Mapping terms to UMLS concepts; 2) Restricting UMLS concepts to MeSH; and 3) Mapping MeSH terms to disease categories. When applied to the automatic classification of condition terms into broad disease categories in the Clinical Trials database, this method assigned relevant categories to 92% of the 1823 condition terms encountered. 135 (7%) failed to be classified and 14 (.77%) were misclassified. The limits of this method are discussed, as well as the reuse of existing components, and the tuning required to achieve automatic classification.

Algorithms↗

PubMedDate not supplied

Clinical diagnostic and intervention studies of children with semantic-pragmatic language disorder.

The diagnosis of semantic-pragmatic language disorder (SPLD) has been the subject of a number of research studies over the last two decades. Classification and diagnostic debates, while illuminating, have done little to develop tools to improve services to these children. In this paper, two children whose communication difficulties are suggestive of an SPLD diagnosis but who have differing profiles are studied. Using existing models of psycholinguistics and pragmatics to guide assessment and intervention, the diversity of language and social communicative behaviours that are covered by the label SPLD are exemplified. Consideration is given to whether the term SPLD is appropriate for both children or whether Bishop's revision of the diagnosis to 'pragmatic language impairment' might be more useful. Methods of intervention and evaluation for semantic and pragmatic deficits in these two cases are described. It is argued that existing tools can enable accurate explanation and modelling of the communication of children with SPLD and that there is a role for intervention studies in helping to refine those tools, to improve therapies and to understand the nature of the condition more fully.

Child↗

PubMed1975

Social class and preschool language skill: II. semantic mastery of color information.

The four-year-old children of Head Start (two-year-classes of 90 for 1969-71 and 72 for 1971-72) performed on a test of perceptual identification approximately as well as four-year-old nursery-school children of parents predominantly of college background. On the other hand, only 28.9% and 19.4% of the children of Head Start, as compared with 87.9% and 90.2% of the children of the nursery-school pointed correctly to all six of the blocks when the examiner named the colors. Also, only 25.6% and 23.6% of those of Head Start, as compared with 81.8% and 76.5% of those of the nursery school, named the colors of all six blocks as they were designated by the examiners. Sex differences and race differences, except in the case of brown, among the children of Head Start were negligible and not significant. Somewhat more children showed semantic mastery for the warn colors, orange and red, than for the cool colors, blue and green. The finding of a deficiency in semantic mastery for such an elementary abstraction as color is highly dissonant with the contention of many students of sociological linguistics that children of poverty, and especially black children of poverty, are without cognitive or linguistic deficit, and that they fail in school only because they use a dialect differing from standard English. The finding is quite consonant with the contention that children of poverty do have a cognitive and linguistic deficit which may, and probably does, derive from the rearing conditions in their homes during the preschool years.

Black or African American↗

PubMed1975

Social class and preschool language skill: III. Semantic mastery of position information.

The four-year-old children of Head Start (two-year-classes of 90 for 1970-71 and 67 for 1971-72) performed on a test of perceptual identification of a sample of six positions approximately as well as did four-year-olds of parents with predominantly college backgrounds. On the other hand, only 22% and 16% of those of Head Start as compared with 70% and 67% of those of the nursery school placed blocks in all six positions that they heard the examiner name, and only 12% and 9% of the former as compared with 45.5% and 44.9% of the latter gave appropriate names for all the six positions designated by the examiner. Sex differences and differences between black and white children of Head Start were negligible and not significant. Somewhat more children of both Head Start and the nursery school showed semantic mastery based on both heard and spoken identification for positions based on body-object relations (in, on, and under) than for those based on object-object relations (in fromt of, between, and in back of). The fact that the children of Head Start perform so much less well than those of the nursery school on the test semantic mastery for position information is highly dissonant with the contention that children of poverty are without either cognitive or linguistic deficit, but quite consonant with the contention that they suffer a deficit that may well and probably does result from the rearing conditions in their homes during the preschool years.

Black or African American↗