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Biomedical subjects

H L Swanson

Publications and source records attributed to H L Swanson.

At least 19 recordsLinked to original sources
PubMed1991

Naturalistic memory in learning-disabled and skilled readers.

Three experiments compared learning-disabled and skilled readers' performance on naturalistic memory measures, as well as investigated the relationship between memory performance on everyday and laboratory tasks. In Experiment 1, the laboratory task (sentence span task) and everyday memory measures were correlated moderately for both ability groups. Compared to skilled readers, disabled readers performed poorly on the sentence span task, and were less likely than skilled readers to remember information related to common objects and consequential events. Disabled readers were also less likely to rely on external prompts to help them recall everyday information. Experiment 2 extended the previous findings to older subjects and found that the majority of significant correlations between the laboratory (word span task) and everyday memory tasks were isolated to disabled readers. When compared to chronological-age-matched subjects, disabled readers were inferior in recency performance on the laboratory (word span) and natural serial recall (e.g., recall of U.S. presidents) tasks. Experiment 3 showed that under conditions that facilitate item accessibility, ability group differences in recall were comparable. Taken together, the findings indicate that disabled readers' memory deficits are pervasive across naturalistic and laboratory measures at the younger age, but these deficits diminish for older students. Further, the deficits that occur at the older age are due to problems in accessing knowledge.

Achievement↗
PubMed1991

Learning disabilities, distinctive encoding, and hemispheric resources.

The purpose of this study was to isolate possible sources of learning ability differences in distinctive encoding of item-specific and relational information. Two mechanisms postulated as underlying ability group differences were attentional capacity (as inferred from the magnitude and direction of correlations between primary and secondary recall) and resource monitoring strategies (as reflected in measures of selective attention and laterality). In Experiment 1, learning disabled and nondisabled childrens' word recall was compared on dichotic listening recall tasks that included nonorienting instructions, and orienting instructions that directed children's attention toward semantic, phonemic, or structural word features. Disabled children showed lower recall and more diffuse selective attention to word features than nondisabled children. Reciprocity (negative correlations) between targeted and background words within and between ability groups was comparable, except when targeted word features were phonemically organized. Experiment 2 indicated that disabled childrens' cued recall was inferior to that of nondisabled children, even though both ability groups produced comparable symmetrical recall patterns related to ear presentations. Taken together, the results suggest that the locus of disabled childrens' distinctive encoding deficiencies is related to resource monitoring strategies during interhemispheric processing.

Attention↗
PubMed1990

Executive processing differences between learning-disabled, mildly retarded, and normal achieving children.

This study examined possible executive processing differences between mildly retarded, learning-disabled, and normal achieving children. To this end, the groups were compared as to their ability to recall central and secondary words from base and elaborative sentences under conditions of high and low encoding effort. Executive processing was inferred from the children's ability to maintain optimal recall performance for central and secondary words. Groups were comparable in central recall, but differences in secondary recall occurred for the high-effort encoding condition. Qualitative differences related to the prioritizing of resources (as reflected in the correlation between central and secondary recall) and monitoring the transfer of information (as reflected from central and secondary recall insertions) were found between groups. The results were discussed in terms of an executive processing framework that views retarded children as suffering from inefficiencies related to the sharing of resources, whereas the learning-disabled children's inefficiencies were related to the discrimination of resources.

Achievement↗
PubMed1990

Can learning disabilities be determined from working memory performance?

This study assumes that children of various academic abilities may be characterized by different patterns of memory function. To test this assumption, subgroups of children were identified through a hierarchical cluster analysis based upon a test battery of sentence span, preload, and concurrent memory demand tasks. One subtype presented a profile of children with learning disabilities showing severe memory performance deficits, while another subgroup yielded high memory and high academic performance. Four additional subtypes had variations in memory performance, which in turn reflected variations in external criteria related to reading, mathematics, and spelling performance. For each subtype, performance strengths and weaknesses were characterized within Baddeley's (1986) working memory model. The study provides partial validation for the classification of children with learning disabilities on psychometric measures according to patterns of memory performance.

Achievement↗
PubMed1989

Working memory in skilled and less skilled readers.

This study assessed skilled and less skilled readers' working memory performance. Fifty skilled and less skilled readers at two age levels were presented with sentence span and concurrent memory tasks. The span task results indicated that working memory differences exist between reading groups. The concurrent task revealed performance deficits for less skilled readers across verbal and nonverbal conditions, suggesting a central processing deficiency. Age differences were isolated to skilled readers. It was concluded that less skilled readers' working memory deficiencies were pervasive in the sense that they involve deficiencies in memory components related to central executive processing.

Attention↗
PubMed1989

The effects of central processing strategies on learning disabled, mildly retarded, average, and gifted children's elaborative encoding abilities.

The purpose of these studies was to examine potential central processing strategy differences among subgroups of children on a series of elaborative encoding tasks. To this end, two experiments included four ability groups (slow learners, learning disabled, average, and intellectually gifted children) who recalled words embedded in sentences. In general, the results suggest that lower verbal and learning ability subgroups recalled less information during elaboratorive encoding conditions than higher ability groups. More importantly, however, the results indicated that lower ability groups differed from higher ability groups in how they shared, discriminated, and selectively allocated resources between the central and secondary recall tasks. The results were discussed within a framework that views individual differences in encoding as reflecting central processing (i.e., resource monitoring) deficiencies.

Aptitude↗
PubMed1988

Characteristics of frequently cited articles in mental retardation.

The purpose of this article was to identify and characterize prominent journal publications in the field of mental retardation from 1976 to 1985. Based on the frequency of citations in the Social Science Citation Index, 24 prominent articles were identified. Prominent (i.e., frequently cited) articles were compared with randomly selected articles on a number of characteristics (e.g., funding source, research, design, statistical method). Implications related to the characteristics and quality of articles that influence the mental retardation field were discussed.

Humans↗
PubMed1987

What learning-disabled readers fail to retrieve on verbal dichotic tests: a problem of encoding, retrieval, or storage?

Three theoretical models were assessed as a framework for capturing learning-disabled readers' faulty word retrieval. To this end, learning-disabled and skilled readers were compared on verbal dichotic listening tasks for free recall and cued recall of word lists organized by semantic, phonemic, and structural features. The results indicated that disabled readers were comparable on free recall but were inferior to skilled readers on cued recall. No ability group differences were found for categorical and noncategorical recall intrusions during the cued recall phase. Cued recall performance was further analyzed for individual differences in memory trace structure (via the Tulving & Watkins, 1975, reduction method), ear asymmetry, and the allocation of attention to word features prior to cuing. Results indicated that during the cued recall phase, disabled readers' memory traces were inferior in structure to those of skilled readers, even though the two ability groups produced comparable symmetrical recall patterns for the ear presentations. Further, disabled readers had lower selective attention scores for the interhemispheric processing of information prior to cuing than did skilled readers. Taken together, the results suggest that, prior to cued recall, disabled readers suffer from attentional difficulties during interhemispheric processing, which in turn influences the structural formation of their memory trace.

Child↗
PubMed1987

The effects of self-instruction training on a deaf child's semantic and pragmatic production.

Effects of self-instruction training on the communication skills of a profoundly hearing-impaired child were studied. Self-instruction training included modeling a series of problem-solving steps in order to direct communication production. Communication production was operationalized as signed semantic and pragmatic functions. A multiple baseline was used to assess treatment and generalization (treatment variations of person and setting) effects. There was evidence to suggest that self-instruction was immediately effective on pragmatic behaviors but such behaviors were reduced when another person administered treatment. In contrast, self-instruction training had a gradual influence on semantic behaviors and those effects were maintained when treatment included a different person and setting. Implications of the clinical study were discussed.

Behavior Therapy↗
PubMed1987

The combining of multiple hemispheric resources in learning-disabled and skilled readers' recall of words: a test of three information-processing models.

Three theoretical models (additive, independence, maximum rule) that characterize and predict the influence of independent hemispheric resources on learning-disabled and skilled readers' simultaneous processing were tested. Predictions related to word recall performance during simultaneous encoding conditions (dichotic listening task) were made from unilateral (dichotic listening task) presentations. The maximum rule model best characterized both ability groups in that simultaneous encoding produced no better recall than unilateral presentations. While the results support the hypothesis that both ability groups use similar processes in the combining of hemispheric resources (i.e., weak/dominant processing), ability group differences do occur in the coordination of such resources.

Cerebral Cortex↗
PubMed1986

Do semantic memory deficiencies underlie learning disabled readers' encoding processes?

This study investigates the extent to which learning disabled readers' atypical encoding relates to their deficiencies in semantic memory. Inferences related to ability group performance were based on the assumption that encoding involves the matching of incoming information against a featural representation of that information in semantic memory. To this end, learning disabled and nondisabled readers in two age groups were compared on dichotic listening recall tasks that included orienting and nonorienting instructions. Orienting instructions directed children's attention toward semantic, phonemic, or structural word features. Dependent measures were lateralization, free recall, retrieval organization, and selective attention. The efficiency of allocating attentional resources was inferred from correlations between central and incidental recall. Primary results included the following: Disabled and nondisabled readers' ear asymmetry differences were dependent upon age, orienting instructions, and type of word list; disabled readers' recall and organization scores were lower than skilled readers'; however, both ability groups benefitted from orienting instructions compared to nonorienting instructions; during orienting instructions, disabled readers were less able than skilled readers to divide their attention between target and nontarget word features, especially during interhemispheric processing conditions; and the relative efficiency of allocating attentional resources differed qualitatively between the two ability groups. The results suggest that ability group variations reflect the structure of the memory trace in interaction with ear presentation and encoding processes. It is inferred that disabled readers' inferior memory traces reflect the quantity and internal coherence of information stored in semantic memory as well as the means by which such information is accessed.

Attention↗