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Biomedical subjects

F R Vellutino

Publications and source records attributed to F R Vellutino.

At least 19 recordsLinked to original sources

Age changes in the missing-letter effect reflect the reader's growing ability to extract the structure from text.

Readers searching for a target letter in text are more likely to miss it in frequent function words than in less frequent content words, and the magnitude of this effect increases with age. While this increase has been taken to indicate that proficient readers process familiar words in terms of larger orthographic units, we propose that it reflects the reader's growing ability to extract the structure of text, resulting in a reduced emphasis on function than on content words. Indeed, comparing 2nd graders (7 to 7 1/2 years) and college students (Experiment 1) this increase was found even when function and content words were equated for frequency. Scrambling words within a sentence (Experiment 2) improved letter detection in function compared to content words among 7th graders (12 to 13 years) and college students, but not among 3rd graders (8 to 9 years). Although letter detection was also affected by word frequency, the age differences noted above are possibly due not to the increasing familiarity of words, but rather to the growing sensitivity to their structural role in text.

Adolescent↗

Normal reading despite limited eye movements.

Many investigators have demonstrated that poor readers exhibit abnormal eye movements during reading. An association between defective vergence, accommodation, and poor reading skills has also been noted by some investigators. Children who are poor readers have been subjected to therapeutic interventions on the basis of the assumption that improving their eye movements, as part of a multifaceted program of "vision therapy," will yield commensurate improvement in reading performance. This approach has been controversial, and other authors have expressed opposing views. We report the ophthalmologic and reading assessments of two children with Möbius' syndrome who were average to above-average readers despite essentially absent horizontal eye movements.

Adolescent↗

Semantic and phonological coding in poor and normal readers.

Three studies were conducted evaluating semantic and phonological coding deficits as alternative explanations of reading disability. In the first study, poor and normal readers in second and sixth grade were compared on various tests evaluating semantic development as well as on tests evaluating rapid naming and pseudoword decoding as independent measures of phonological coding ability. In a second study, the same subjects were given verbal memory and visual-verbal learning tasks using high and low meaning words as verbal stimuli and Chinese ideographs as visual stimuli. On the semantic tasks, poor readers performed below the level of the normal readers only at the sixth grade level, but, on the rapid naming and pseudoword learning tasks, they performed below the normal readers at the second as well as at the sixth grade level. On both the verbal memory and visual-verbal learning tasks, performance in poor readers approximated that of normal readers when the word stimuli were high in meaning but not when they were low in meaning. These patterns were essentially replicated in a third study that used some of the same semantic and phonological measures used in the first experiment, and verbal memory and visual-verbal learning tasks that employed word lists and visual stimuli (novel alphabetic characters) that more closely approximated those used in learning to read. It was concluded that semantic coding deficits are an unlikely cause of reading difficulties in most poor readers at the beginning stages of reading skills acquisition, but accrue as a consequence of prolonged reading difficulties in older readers. It was also concluded that phonological coding deficits are a probable cause of reading difficulties in most poor readers.

Child↗

Dyslexia.

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Dyslexia↗

Free recall of concrete and abstract words in poor and normal readers.

The present study compared poor and normal readers in second and sixth grade on free recall of concrete and abstract words. On the basis of the assumption that memory for abstract words relies more heavily upon linguistic coding ability than does memory for concrete words, it was expected that poor readers would have much greater difficulty on recall of abstract words than would normal readers, but would more closely approximate the normal readers on recall of concrete words. The hypothesis was confirmed at the second-grade level but not at the sixth-grade level, wherein the magnitude of group differences on concrete words was comparable to that on abstract words. Post hoc analyses of intrusion errors suggested that the linguistic coding hypothesis may be a viable explanation of reader group differences on memory tasks only at lower age levels.

Child↗

Inter- versus intra-hemispheric learning in dyslexic and normal readers.

The present study investigated the hypothesis that developmental dyslexia is attributable to dysfunction in inter-hemispheric transfer. Dyslexic and normal readers in second grade (age-range seven to eight years) and sixth grade (11 to 12 years) were given tachistoscopic presentations of novel visual stimuli (Chinese ideographs), randomly presented to the left and right visual fields and to the central fixation point. Each stimulus was paired with a common English word (spoken) and the children were asked to associate the two. The transmission deficit hypothesis predicts that poor and normal readers will be differentiated in the case of presentations to the right hemisphere (left visual field) but will not differ significantly in the case of presentations to the left hemisphere (right visual field). This hypothesis was not supported. Normal readers at both grade levels performed significantly better than poor readers in both visual-field presentations.

Age Factors↗

Visual form perception in deficient and normal readers as a function of age and orthographic-linguistic familiarity.

The present investigation directly assessed the hypothesis that poor readers sustain no basic disorder in visual-spatial functioning. In order to extend pervious results to younger children, the performance of poor and normal readers from both the second and sixth grades was compared. Adopting the format of an earlier investigation, a visual recall task was employed as the dependent variable, and it was predicted that poor readers would perform as well as normals with stimuli taken from Hebrew, an unfamiliar orthography. Accordingly, non-Hebrew poor and normal readers were compared with normal readers learning Hebrew on the production of varying length Hebrew words. As anticipated, children in the non Hebrew reader groups performed comparably on this task, but the performance of these subjects was inferior to that of children in the Hebrew groups. The data support the contention that visual perceptual disorder is an unlikely source of reading disability.

Age Factors↗

Differential transfer in poor and normal readers.

It has been suggested that children who sustain specific reading disability experience difficulty in abstracting and generalizing the invariant components of words containing redundant elements because of basic dysfunction in categorical processing. This hypothesis was assessed by comparing independent samples of poor and normal readers on transfer of training tasks of two different types: a visual-verbal association task which simulated the reading process, and a visual-visual association task unlike reading. It was predicted that poor readers would perform significantly below normal readers on both initial learning and transfer under the visual-verbal association conditions. In contrast, it was expected that the performance of similar groups of poor and normal readers would be comparable under the visual-visual training and transfer conditions. The results supported these predictions, and it was concluded that the generalization problems observed in poor readers in early word learning are, most likely, attributable to transfer difficulties associated with specific disorder in visual-verbal integration, rather than primary or basic disorder in categorization ability.

Achievement↗

Reading disability: age differences and the perceptual-deficit hypothesis.

The present study assessed the suggestion that specific reading disability is caused by visual-spatial disorder. A previous investigation questioned this hypothesis in demonstrating that poor readers' orientation errors (e.g., b/d; was/saw) result from malfunction in verbal identification rather than optical distortion. However, the generality of its findings was limited by the fact that its subject included only children at the upper age levels (9-15 years). In order to extend our results to younger children, poor and normal readers in the second and sixth grades were presented with tachistoscopic exposures of both verbal and nonverbal stimuli and were asked to identify and/or reproduce them both orally and graphically. With some exceptions, the results obtained in the previous study were replicated: the performance of poor readers at both age levels closely approximated that of normals in visual as compared with verbal encoding.

Adolescent↗