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.

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.

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.

Free recall and abstractness of stimuli.

The relation of abstractness of stimuli to efficiency of free recall was studied in college and fourth-grade students. Groups were shown a sequence of objects, pictures, and object names and were asked to recall what they had seen. Recall tests were conducted either immediately after presentation of the stimulus-sequence, after 24 hours, or after 1 week. Objects were recalled more frequently than pictures, and pictures more frequently than words. Adults performed better than children, except in the case of objects.